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  • 151.
    Nässtrom, M.
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Psykiatri.
    Eriksson, J.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Blomstedt, P.
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap.
    Bodlund, O.
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Psykiatri.
    FMRI evaluation of deep brain stimulation in obsessive-compulsive disorder2019Inngår i: European psychiatry, ISSN 0924-9338, E-ISSN 1778-3585, Vol. 56, s. S566-S566Artikkel i tidsskrift (Annet vitenskapelig)
  • 152.
    Olsson, Carl-Johan
    Umeå universitet, Samhällsvetenskapliga fakulteten, Centrum för befolkningsstudier (CBS). Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Complex motor representations may not be preserved after complete spinal cord injury2012Inngår i: Experimental Neurology, ISSN 0014-4886, E-ISSN 1090-2430, Vol. 236, nr 1, s. 46-49Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    When using motor imagery to improve rehabilitation after spinal cord injury it is assumed that the motor representations are preserved and that task specific physical training is not necessary. Here I tested this hypothesis by examining P.W. who has a complete spinal cord injury due to an accident. However, P.W. was an elite wheelchair athlete, hence, has experienced a high load of physical training in general. During functional magnetic resonance imaging (fMRI). P.W. imagined wheelchair slalom (a complex motor task P.W. can perform) and stair walking (a complex motor task P.W. no longer can perform). A control group of neurologically intact participants were also included. The results showed that only for the task (wheelchair slalom) P.W. currently could physically perform was the pre-motor cortex recruited. For stair walking P.W. recruited inferior frontal cortex and parietal cortex. The results were confirmed with the control group showing similar pattern but for the opposite tasks. The conclusions from this study are that complex motor representations may not be preserved after a complete spinal cord injury and motor imagery is dependent on the current ability to perform the task physically. (C) 2012 Elsevier Inc. All rights reserved.

  • 153.
    Olsson, Carl-Johan
    Umeå universitet, Samhällsvetenskapliga fakulteten, Centrum för befolkningsstudier (CBS). Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    The Aging Brain and what we can do about it: an introduction2013Konferansepaper (Annet vitenskapelig)
  • 154.
    Olsson, Carl-Johan
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Centrum för befolkningsstudier (CBS). Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Hedlund, Mattias
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Sjukgymnastik.
    Sojka, Peter
    Department of Health Sciences, Mid-Sweden University, Östersund, Sweden.
    Lundström, Ronnie
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Yrkes- och miljömedicin.
    Lindström, Britta
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Sjukgymnastik.
    Increased prefrontal activity and reduced motor cortex activity during imagined eccentric compared to concentric muscle actions2012Inngår i: Frontiers in Human Neuroscience, ISSN 1662-5161, E-ISSN 1662-5161, Vol. 6, nr 255Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study we used functional magnetic resonance imaging (fMRI) to examine differences in recruited brain regions during the concentric and the eccentric phase of an imagined maximum resistance training task of the elbow flexors in healthy young subjects. The results showed that during the eccentric phase, pre-frontal cortex (BA44) bilaterally was recruited when contrasted to the concentric phase. During the concentric phase, however, the motor and pre-motor cortex (BA 4/6) was recruited when contrasted to the eccentric phase. Interestingly, the brain activity of this region was reduced, when compared to the mean activity of the session, during the eccentric phase. Thus, the neural mechanisms governing imagined concentric and eccentric contractions appear to differ. We propose that the recruitment of the pre-frontal cortex is due to an increased demand of regulating force during the eccentric phase. Moreover, it is possible that the inability to fully activate a muscle during eccentric contractions may partly be explained by a reduction of activity in the motor and pre-motor cortex.

  • 155.
    Olsson, Carl-Johan
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi.
    Jonsson, Bert
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Larsson, Anne
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi. Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Motor representations and practice affect brain systems underlying imagery: an FMRI study of internal imagery in novices and active high jumpers2008Inngår i: The Open Neuroimaging Journal, ISSN 1874-4400, E-ISSN 1874-4400, Vol. 2, s. 5-13Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study used functional magnetic resonance imaging (fMRI) to investigate differences in brain activity between one group of active high jumpers and one group of high jumping novices (controls) when performing motor imagery of a high jump. It was also investigated how internal imagery training affects neural activity. The results showed that active high jumpers primarily activated motor areas, e.g. pre-motor cortex and cerebellum. Novices activated visual areas, e.g. superior occipital cortex. Imagery training resulted in a reduction of activity in parietal cortex. These results indicate that in order to use an internal perspective during motor imagery of a complex skill, one must have well established motor representations of the skill which then translates into a motor/internal pattern of brain activity. If not, an external perspective will be used and the corresponding brain activation will be a visual/external pattern. Moreover, the findings imply that imagery training reduces the activity in parietal cortex suggesting that imagery is performed more automatic and results in a more efficient motor representation more easily accessed during motor performance.

  • 156.
    Olsson, Carl-Johan
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Jonsson, Bert
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB). Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Learning by doing and learning by thinking: An fMRI study of combining motor and mental training2008Inngår i: Frontiers in human neuroscience, ISSN 1662-5161, Vol. 2, nr 5, s. 1-7Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [sv]

    The current study investigated behavioral and neural effects of motor, mental, and combined motor and mental training on a finger tapping task. The motor or mental training groups trained on a finger-sequence for a total of 72 min over six weeks. The motor and mental training group received 72 min motor training and in addition 72 min mental training. Results showed that all groups increased their tapping performance significantly on the trained sequence. After training fMRI data was collected and indicated training specific increases in ventral pre-motor cortex following motor training, and in fusiform gyrus following mental training. Combined motor and mental training activated both the motor and the visual regions. In addition, motor and mental training showed a significant increase in tapping performance on an untrained sequence (transfer). FMRI scanning indicated that the transfer effect involved the cerebellum. Conclusions were that combined motor and mental training recruited both motor and visual systems, and that combined motor and mental training improves motor flexibility via connections from both motor and cognitive systems to the cerebellum.

  • 157.
    Olsson, Carl-Johan
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Centrum för befolkningsstudier (CBS). Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Lundström, Peter
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Using action observation to study superior motor performance: a pilot fMRI study2013Inngår i: Frontiers in Human Neuroscience, ISSN 1662-5161, E-ISSN 1662-5161, Vol. 7, artikkel-id 819Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The most efficient way to acquire motor skills may be through physical practice. Nevertheless, it has also been shown that action observation may improve motor performance. The aim of the present pilot study was to examine a potential action observation paradigm used to (1) capture the superior performance of expert athletes and (2) capture the underlying neural mechanisms of successful action observation in relation to task experience. We used functional magnetic resonance imaging to measure regional blood flow while presenting videos of a hockey player shooting a puck toward a hockey goal. The videos (a total of 120) where stopped at different time frames with different amount of information provided, creating a paradigm with three different levels of difficulty to decide the fate of a shot. Since this was only a pilot study, we first tested the paradigm behaviorally on six elite expert hockey players, five intermediate players, and six non-hockey playing controls. The results showed that expert hockey players were significantly (p < 0.05) more accurate on deciding the fate of the action compared to the others. Thus, it appears as if the paradigm can capture superior performance of expert athletes (aim 1). We then tested three of the hockey players and three of the controls on the same paradigm in the MRI scanner to investigate the underlying neural mechanisms of successful action anticipation. The imaging results showed that when expert hockey players observed and correctly anticipated situations, they recruited motor and temporal regions of the brain. Novices, on the other hand, relied on visual regions during observation and prefrontal regions during action decision. Thus, the results from the imaging data suggest that different networks of the brain are recruited depending on task experience (aim 2). In conclusion, depending on the level of motor skill of the observer, when correctly anticipating actions different neural systems will be recruited.

  • 158.
    Olsson, Carl-Johan
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Idrottsmedicin. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi. Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Brain simulation of action may be grounded in physical experience2011Inngår i: Neurocase, ISSN 1355-4794, E-ISSN 1465-3656, Vol. 17, nr 6, s. 501-505Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An intriguing quality of our brain is that when actions are imagined, corresponding brain regions are recruited as when the actions are actually performed. It has been hypothesized that the similarity between real and simulated actions depends on the nature of motor representations. Here we tested this hypothesis by examining S.D., who never used her legs but is an elite wheel chair athlete. Controls recruited motor brain regions during imagery of stair walking and frontal regions during imagery of wheel chair slalom. S.D. showed the opposite pattern. Thus, brain simulation of actions may be grounded in specific physical experiences.

  • 159.
    Olsson, Carl-Johan
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi.
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Motor imagery: if you can't do it, you won't think it2010Inngår i: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 20, nr 5, s. 711-715Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Since long, motor imagery has been recognized as a method for studying motor representations. In the last few years, important advances regarding the use of motor imagery have been made. In particular, issues concerning the functional equivalence between imagery and action have been addressed, and how equivalence affects the use of imagery to study motor representations. In this paper, we review recent findings in order to highlight the current state of knowledge about motor imagery and its relation to motor action. Three topics are discussed: (i) the imagery perspective, (ii) task complexity, and (iii) the importance of physical experience. It is shown how theses factors are closely related and how previous studies may have underestimated to what extent these factors affect the interpretation of results. Practical implications for imagery interventions are considered. It is concluded that if you cannot perform an action physically, you cannot imagine it in a way that is necessary for a high degree of functional equivalence.

  • 160.
    Oudin, Anna
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Yrkes- och miljömedicin.
    Forsberg, Bertil
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Yrkes- och miljömedicin.
    Nordin Adolfsson, Annelie
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Psykiatri.
    Lind, Nina
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Modig, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Yrkes- och miljömedicin.
    Nordin, Maria
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Nordin, Steven
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Adolfsson, Rolf
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Psykiatri.
    Nilsson, Lars-Göran
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Aging research centre, Karolinska Institutet.
    Traffic-Related Air Pollution and Dementia Incidence in Northern Sweden: A Longitudinal Study2016Inngår i: Journal of Environmental Health Perspectives, ISSN 0091-6765, E-ISSN 1552-9924, Vol. 124, nr 3, s. 306-312Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BACKGROUND: Exposure to ambient air pollution is suspected to cause cognitive effects, but a prospective cohort is needed to study exposure to air pollution at the home address and the incidence of dementia.

    OBJECTIVES: We aimed to assess the association between long-term exposure to traffic-related air pollution and dementia incidence in a major city in northern Sweden.

    METHODS: Data on dementia incidence over a 15-year period were obtained from the longitudinal Betula study. Traffic air pollution exposure was assessed with a Land Use Regression Model with a spatial resolution of 50 m x 50 m. Annual mean nitrogen oxide levels at the residential address of the participants at baseline (the start of follow-up) was used as a marker for long-term exposure to air pollution.

    RESULTS: Out of 1806 participants at baseline, 191 were diagnosed with Alzheimer's disease during follow-up, and 111 were diagnosed with vascular dementia. Participants in the highest exposure group were more likely to be diagnosed with dementia (Alzheimer's disease or vascular dementia), with a Hazard Ratio (HR) of 1.43 (95% Confidence Interval (CI): 0.998, 2.05 for the highest versus lowest quartile). The estimates were similar for Alzheimer's disease (HR 1.38) and vascular dementia (HR 1.47). The HR for dementia associated for the third quartile versus the lowest quartile was 1.48 (95% CI: 1.03, 2.11). A sub-analysis that excluded a younger sample that had been re-tested after only 5 years of follow-up suggested stronger associations with exposure than in the full cohort (HR = 1.71; 95% CI: 1.08, 2.73 for the highest versus lowest quartile).

    CONCLUSIONS: If the associations we observed are causal, then air pollution from traffic might be an important risk factor for vascular dementia and Alzheimer's disease.

  • 161.
    Papenberg, Goran
    et al.
    Aging Research Center, Karolinska Institutet and Stockholm University, Gävlegatan 16, 113 30, Stockholm, Sweden.
    Salami, Alireza
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Aging Research Center, Karolinska Institutet and Stockholm University, Gävlegatan 16, 113 30, Stockholm, Sweden.
    Persson, Jonas
    Aging Research Center, Karolinska Institutet and Stockholm University, Gävlegatan 16, 113 30, Stockholm, Sweden.
    Lindenberger, Ulman
    Berlin, Germany; London, UK.
    Bäckman, Lars
    Aging Research Center, Karolinska Institutet and Stockholm University, Gävlegatan 16, 113 30, Stockholm, Sweden.
    Genetics and Functional Imaging: Effects of APOE, BDNF, COMT, and KIBRA in Aging2015Inngår i: Neuropsychology Review, ISSN 1040-7308, E-ISSN 1573-6660, Vol. 25, nr 1, s. 47-62Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Increasing evidence from cross-sectional and longitudinal molecular-genetic studies suggests that effects of common genetic variations on cognitive functioning increase with aging. We review the influence of candidate genes on brain functioning in old age, focusing on four genetic variations that have been extensively investigated: APOE, BDNF, COMT, and KIBRA. Similar to the behavioral evidence, there are reports from age-comparative studies documenting stronger genetic effects on measures of brain functioning in older adults compared to younger adults. This pattern suggests disproportionate impairments of neural processing among older individuals carrying disadvantageous genotypes. We discuss various factors, including gene-gene interactions, study population characteristics, lifestyle factors, and diseases, that need to be considered in future studies and may help understand inconsistent findings in the extant literature.

  • 162.
    Pedale, Tiziana
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB). Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Department of Psychology, Sapienza University of Rome, Via dei Marsi, 78, 00158 Rome, Italy; Neuroimaging Laboratory, IRCCS Santa Lucia Foundation, Via Ardeatina, 306, 00179 Rome, Italy.
    Macaluso, Emiliano
    Santangelo, Valerio
    Enhanced insular/prefrontal connectivity when resisting from emotional distraction during visual search2019Inngår i: Brain Structure and Function, ISSN 1863-2653, E-ISSN 1863-2661, Vol. 224, nr 6, s. 2009-2026Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Previous literature demonstrated that the processing of emotional stimuli can interfere with goal-directed behavior. This has been shown primarily in the context of working memory tasks, but emotional distraction may affect also other processes, such as the orienting of visuo-spatial attention. During fMRI, we presented human subjects with emotional stimuli embedded within complex everyday life visual scenes. Emotional stimuli could be either the current target to be searched for or task-irrelevant distractors. Behavioral and eye-movement data revealed faster detection of emotional than neutral targets. Emotional distractors were found to be fixated later and for a shorter duration than emotional targets, suggesting efficient top-down control in avoiding emotional distraction. The fMRI data demonstrated that negative (but not positive) stimuli were mandatorily processed by limbic/para-limbic regions (namely, the right amygdala and the left insula), irrespective of current task relevance: that is, these regions activated for both emotional targets and distractors. However, analyses of inter-regional connectivity revealed a functional coupling between the left insula and the right prefrontal cortex that increased specifically during search in the presence of emotional distractors. This indicates that increased functional coupling between affective limbic/para-limbic regions and control regions in the frontal cortex can attenuate emotional distraction, permitting the allocation of spatial attentional resources toward task-relevant neutral targets in the presence of distracting emotional signals.

  • 163.
    Persson, Jonas
    et al.
    Stockholm Univ, Dept Psychol, S-10691 Stockholm, Sweden .
    Pudas, Sara
    Stockholm Univ, Dept Psychol, S-10691 Stockholm, Sweden .
    Lind, Johanna
    Stockholm Univ, Dept Psychol, S-10691 Stockholm, Sweden .
    Kauppi, Karolina
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi. Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi.
    Nilsson, Lars-Göran
    Stockholm Univ, Dept Psychol, S-10691 Stockholm, Sweden .
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi.
    Longitudinal structure-function correlates in elderly reveal MTL dysfunction with cognitive decline2012Inngår i: Cerebral Cortex, ISSN 1047-3211, E-ISSN 1460-2199, Vol. 22, nr 10, s. 2297-2304Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    By integrating behavioral measures and imaging data, previous investigations have explored the relationship between biological markers of aging and cognitive functions. Evidence from functional and structural neuroimaging has revealed that hippocampal volume and activation patterns in the medial temporal lobe (MTL) may predict cognitive performance in old age. Most past demonstrations of age-related differences in brain structure-function were based on cross-sectional comparisons. Here, the relationship between 6-year intraindividual change in functional magnetic resonance imaging (fMRI) signal and change in memory performance over 2 decades was examined. Correlations between intraindividual change in fMRI signal during episodic encoding and change in memory performance measured outside of scanning were used as an estimate for relating brain-behavior changes. The results revealed a positive relationship between activation change in the hippocampus (HC) and change in memory performance, reflecting reduced hippocampal activation in participants with declining performance. Using a similar analytic approach as for the functional data, we found that individuals with declining performance had reduced HC volume compared with individuals with intact performance. These observations provide a strong link between cognitive change in older adults and MTL structure and function and thus provide insights into brain correlates of individual variability in aging trajectories.

  • 164.
    Persson, Jonas
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Department of Psychology, Aging Research Center (ARC) at Karolinska Institute and Stockholm University, Stockholm, Sweden and Department of Psychology, Stockholm University, Stockholm, Sweden.
    Pudas, Sara
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Department of Psychology, Stockholm University, Stockholm, Sweden.
    Nilsson, Lars-Göran
    Karolinska Inst, Aging Res Ctr ARC, S-11330 Stockholm, Sweden and Stockholm Univ, Dept Psychol, S-11330 Stockholm, Sweden.
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Longitudinal assessment of default-mode brain function in aging2014Inngår i: Neurobiology of Aging, ISSN 0197-4580, E-ISSN 1558-1497, Vol. 35, nr 9, s. 2107-2117Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Age-related changes in the default-mode network (DMN) have been identified in prior cross-sectional functional magnetic resonance imaging studies. Here, we investigated longitudinal change in DMN activity and connectivity. Cognitively intact participants (aged 49-79 years at baseline) were scanned twice, with a 6-year interval, while performing an episodic memory task interleaved with a passive control condition. Longitudinal analyses showed that the DMN (control condition > memory task) could be reliably identified at both baseline and follow-up. Differences in the magnitude of task-induced deactivation in posterior DMN regions were observed between baseline and follow-up indicating reduced deactivation in these regions with increasing age. Although no overall longitudinal changes in within-network connectivity were found across the whole sample, individual differences in memory change correlated with change in connectivity. Thus, our results show stability of whole-brain DMN topology and functional connectivity over time in healthy older adults, whereas within-region DMN analyses show reduced deactivation between baseline and follow-up. The current findings provide novel insights into DMN functioning that may assist in identifying brain changes in patient populations, as well as characterizing factors that distinguish between normal and pathologic aging.

  • 165.
    Persson, Jonas
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Karolinska Inst, ARC, S-11330 Stockholm, Sweden; Stockholm Univ, S-11330 Stockholm, Sweden; Stockholm Univ, Dept Psychol, S-11330 Stockholm, Sweden.
    Rieckmann, Anna
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Massachusetts Gen Hosp, Athinoula A Martinos Ctr Biomed Imaging, Charlestown, MA USA.
    Kalpouzos, Grégoria
    Fischer, Håkan
    Bäckman, Lars
    Influences of a DRD2 polymorphism on updating of long-term memory representations and caudate BOLD activity: magnification in aging2015Inngår i: Human Brain Mapping, ISSN 1065-9471, E-ISSN 1097-0193, Vol. 36, nr 4, s. 1325-1334Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A number of genetic polymorphisms are related to individual differences in cognitive performance. Striatal dopamine (DA) functions, associated with cognitive performance, are linked to the TaqIA polymorphism of the DRD2/ANKK1 gene. In humans, presence of an A1 allele of the DRD2/ANKK1-TaqIA polymorphism is related to reduced density of striatal DA D2 receptors. The resource-modulation hypothesis assumes that aging-related losses of neurochemical and structural brain resources modulate the extent to which genetic variations affect cognitive functioning. Here, we tested this hypothesis using functional MRI during long-term memory (LTM) updating in younger and older carriers and noncarriers of the A1-allele of the TaqIa polymorphism. We demonstrate that older A1-carriers have worse memory performance, specifically during LTM updating, compared to noncarriers. Moreover, A1-carriers exhibited less blood oxygen level-dependent (BOLD) activation in left caudate nucleus, a region critical to updating. This effect was only seen in older adults, suggesting magnification of genetic effects on functional brain activity in aging. Further, a positive relationship between caudate BOLD activation and updating performance among non-A1 carriers indicated that caudate activation was behaviorally relevant. These results demonstrate a link between the DRD2/ANKK1-TaqIA polymorphism and neurocognitive deficits related to LTM updating, and provide novel evidence that this effect is magnified in aging. Hum Brain Mapp 36:1325-1334, 2015.

  • 166.
    Pudas, Sara
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB). Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Aging of memory and brain functions: usual and successful2016Inngår i: From Neuroscience to Neurospyschology: the study of the human brain. Volume II / [ed] Alexandra Isabel Dias Reis & Luis Faísca, Bogotá, Colombia: Ediciones Corporación Universitaria Reformada , 2016, 1, s. 163-192Kapittel i bok, del av antologi (Fagfellevurdert)
  • 167.
    Pudas, Sara
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Josefsson, Maria
    Umeå universitet, Samhällsvetenskapliga fakulteten, Enheten för demografi och åldrandeforskning (CEDAR).
    Rieckmann, Anna
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Longitudinal evidence for increased functional response in frontal cortex for older adults with hippocampal atrophy and memory decline2018Inngår i: Cerebral Cortex, ISSN 1047-3211, E-ISSN 1460-2199, Vol. 28, nr 3, s. 936-948Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The functional organization of the frontal cortex is dynamic. Age-related increases in frontal functional responses have been shown during various cognitive tasks, but the cross-sectional nature of most past studies makes it unclear whether these increases reflect reorganization or stable individual differences. Here, we followed 130 older individuals' cognitive trajectories over 20-25 years with repeated neuropsychological assessments every 5th year, and identified individuals with stable or declining episodic memory. Both groups displayed significant gray matter atrophy over 2 successive magnetic resonance imaging sessions 4 years apart, but the decline group also had a smaller volume of the right hippocampus. Only individuals with declining memory demonstrated increased prefrontal functional responses during memory encoding and retrieval over the 4-year interval. Regions with increased functional recruitment were located outside, or on the borders of core task-related networks, indicating an expansion of these over time. These longitudinal findings offer novel insight into the mechanisms behind age-associated memory loss, and are consistent with a theoretical model in which hippocampus atrophy, past a critical threshold, induces episodic-memory decline and altered prefrontal functional organization.

  • 168.
    Pudas, Sara
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Persson, Jonas
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Josefsson, Maria
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    de Luna, Xavier
    Umeå universitet, Samhällsvetenskapliga fakulteten, Statistiska institutionen.
    Nilsson, Lars-Göran
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi.
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Brain Characteristics of Individuals Resisting Age-Related Cognitive Decline over Two Decades2013Inngår i: Journal of Neuroscience, ISSN 0270-6474, E-ISSN 1529-2401, Vol. 33, nr 20, s. 8668-8677Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Some elderly appear to resist age-related decline in cognitive functions, but the neural correlates of successful cognitive aging are not well known. Here, older human participants from a longitudinal study were classified as successful or average relative to the mean attrition-corrected cognitive development across 15-20 years in a population-based sample (n = 1561). Fifty-one successful elderly and 51 age-matched average elderly (mean age: 68.8 years) underwent functional magnetic resonance imaging while performing an episodic memory face-name paired-associates task. Successful older participants had higher BOLD signal during encoding than average participants, notably in the bilateral PFC and the left hippocampus (HC). The HC activation of the average, but not the successful, older group was lower than that of a young reference group (n = 45, mean age: 35.3 years). HC activation was correlated with task performance, thus likely contributing to the superior memory performance of successful older participants. The frontal BOLD response pattern might reflect individual differences present from young age. Additional analyses confirmed that both the initial cognitive level and the slope of cognitive change across the longitudinal measurement period contributed to the observed group differences in BOLD signal. Further, the differences between the older groups could not be accounted for by differences in brain structure. The current results suggest that one mechanism behind successful cognitive aging might be preservation of HC function combined with a high frontal responsivity. These findings highlight sources for heterogeneity in cognitive aging and may hold useful information for cognitive intervention studies.

  • 169.
    Pudas, Sara
    et al.
    Department of Psychology, Stockholm University, Stockholm, Sweden .
    Persson, Jonas
    Department of Psychology, Stockholm University, Stockholm, Sweden .
    Nilsson, Lars-Göran
    Department of Psychology, Stockholm University, Stockholm, Sweden .
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi. Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Maintenance and manipulation in working memory: Differential ventral and dorsal frontal cortex fMRI activity2009Inngår i: Acta Psychologica Sinica, ISSN 0439-755X, Vol. 41, nr 11, s. 1054-1062Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A verbal working memory protocol was designed and evaluated on a group of healthy younger adults in preparation for a large-scale functional magnetic resonance (fMRI) study on aging and memory. Letters were presented in two critical conditions: (i) maintenance, in which letters were to be memorized and kept in mind over a four second interval, and (ii) manipulation, in which letters were shifted forward in alphabetical order, and the new order was kept in mind. Analyses of fMRI data showed that the protocol elicited reliable activation in the frontal cortex, with manipulation producing more extensive activation patterns, both in whole-brain analyses and in predefined regions of interest (ROIs). There was also a distinction between dorsal and ventral lateral prefrontal regions, such that manipulation elicited more dorsolateral prefrontal activation. The protocol also elicited activation in various subcortical areas, previously associated with working-memory tasks. It was concluded that this working memory protocol is appropriate for investigating age-related changes in frontal-cortex functioning.

  • 170.
    Pudas, Sara
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Persson, Jonas
    Nilsson, Lars-Göran
    Nyberg, Lars
    Maintenance and Manipulation in Working Memory: Differential Ventral and Dorsal Frontal Cortex fMRI Activity2009Inngår i: Acta Psychologica Sinica, Vol. 41, nr 11, s. 1054-1062Artikkel i tidsskrift (Annet vitenskapelig)
  • 171.
    Pudas, Sara
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Department of Psychology, Stockholm University, Stockholm.
    Persson, Jonas
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Department of Psychology, Stockholm University, Aging Research Center, Karolinska Institute and Stockholm University, Stockholm.
    Nilsson, Lars-Göran
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Aging Research Center, Karolinska Institute and Stockholm University, Stockholm.
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Midlife memory ability accounts for brain activity differences in healthy aging2014Inngår i: Neurobiology of Aging, ISSN 0197-4580, E-ISSN 1558-1497, Vol. 35, nr 11, s. 2495-2503Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cross-sectional neuroimaging studies suggest that hippocampal and prefrontal cortex functions underlie individual differences in memory ability in older individuals, but it is unclear how individual differences in cognitive ability in youth contribute to cognitive and neuroimaging measures in older age. Here, we investigated the relative influences of midlife memory ability and age-related memory change on memory-related BOLD-signal variability at one time point, using a sample from a longitudinal population-based aging study (N = 203, aged 55-80 years). Hierarchical regression analyses showed that midlife memory ability, assessed 15-20 years earlier, explained at least as much variance as memory change in clusters in the left inferior prefrontal cortex and the bilateral hippocampus, during memory encoding. Furthermore, memory change estimates demonstrated higher sensitivity than current memory levels in identifying distinct frontal regions where activity was selectively related to age-related memory change, as opposed to midlife memory. These findings highlight challenges in interpreting individual differences in neurocognitive measures as age-related changes in the absence of longitudinal data and also demonstrate the improved sensitivity of longitudinal measures.

  • 172.
    Qvarlander, Sara
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Centrum för medicinsk teknik och fysik (CMTF).
    Ambarki, Khalid
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Centrum för medicinsk teknik och fysik (CMTF).
    Wåhlin, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Jacobsson, Johan
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap.
    Birgander, Richard
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Malm, Jan
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap.
    Eklund, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Centrum för medicinsk teknik och fysik (CMTF).
    Cerebrospinal fluid and blood flow patterns in idiopathic normal pressure hydrocephalus2017Inngår i: Acta Neurologica Scandinavica, ISSN 0001-6314, E-ISSN 1600-0404, Vol. 135, nr 5, s. 576-584Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Objectives: Increased aqueduct cerebrospinal fluid (CSF) flow pulsatility and, recently, a reversed CSF flow in the aqueduct have been suggested as hallmarks of idiopathic normal pressure hydrocephalus (INPH). However, these findings have not been adequately confirmed. Our objective was to investigate the flow of blood and CSF in INPH, as compared to healthy elderly, in order to clarify which flow parameters are related to the INPH pathophysiology.

    Materials and Methods: Sixteen INPH patients (73 years) and 35 healthy subjects (72 years) underwent phase-contrast magnetic resonance imaging (MRI). Measurements included aqueduct and cervical CSF flow, total arterial inflow (tCBF; i.e. carotid + vertebral arteries), and internal jugular vein flow. Flow pulsatility, net flow, and flow delays were compared (multiple linear regression, correcting for sex and age).

    Results: Aqueduct stroke volume was higher in INPH than healthy (148±95 vs 90±50 mL, P<.05). Net aqueduct CSF flow was similar in magnitude and direction. The cervical CSF stroke volume was lower (P<.05). The internal carotid artery net flow was lower in INPH (P<.05), although tCBF was not. No differences were found in internal jugular vein flow or flow delays.

    Conclusions: The typical flow of blood and CSF in INPH was mainly characterized by increased CSF pulsatility in the aqueduct and reduced cervical CSF pulsatility. The direction of mean net aqueduct CSF flow was from the third to the fourth ventricle. Our findings may reflect the altered distribution of intracranial CSF volume in INPH, although the causality of these relationships is unclear.

  • 173.
    Rieckmann, Anna
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Johnson, Keith A.
    Sperling, Reisa A.
    Buckner, Randy L.
    Hedden, Trey
    Dedifferentiation of caudate functional connectivity and striatal dopamine transporter density predict memory change in normal aging2018Inngår i: Proceedings of the National Academy of Sciences, Vol. 115, nr 40, s. 10160-10165Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Age-related changes in striatel function are potentially important for predicting declining memory performance over the adult life span. Here, we used fMRI to measure functional connectivity of caudate subfields with large-scale association networks and positron emission tomography to measure striatal dopamine transporter (DAT) density in 51 older adults (age 65-86 years) who received annual cognitive testing for up to 7 years (mean = 5.59, range 2-7 years). Analyses showed that cortical-caudate functional connectivity was less differentiated in older compared with younger adults (n = 63, age 18-32 years). Unlike in younger adults, the central lateral caudate was less strongly coupled with the frontal parietal control network in older adults. Older adults also showed less "decoupling" of the caudate from other networks, including areas of the default network (DN) and the hippocampal complex. Contrary to expectations, less decoupling between caudate and the DN was not associated with an age-related reduction of striatal DAT, suggesting that neurobiological changes in the cortex may drive dedifferentiation of cortical-caudate connectivity. Reduction of specificity in functional coupling between caudate and regions of the DN predicted memory decline over subsequent years at older ages. The age-related reduction in striatal DAT density also predicted memory decline, suggesting that a relation between striatal functions and memory decline in aging is multifaceted. Collectively, the study provides evidence highlighting the association of age-related differences in striatal function to memory decline in normal aging.

  • 174.
    Rieckmann, Anna
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Pudas, Sara
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Longitudinal Changes in Component Processes of Working Memory2017Inngår i: eNeuro, E-ISSN 2373-2822, Vol. 4, nr 2Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Working memory (WM) entails maintenance and manipulation of information in the absence of sensory input. This study investigated the trajectories and neural basis of these component processes of WM functions in aging. Longitudinal human functional magnetic resonance imaging (fMRI) data are presented from 136 older individuals (55–80 years) who were scanned at baseline and again 4 years later. We obtained evidence that age-related changes in parietal and frontal components of the WM core network are dissociable in terms of their role in maintenance of perceptual representations and further manipulation of this information, respectively. Individual difference analyses in performance subgroups showed that only prefrontal changes in fMRI activation were accompanied by changes in performance, but parietal brain activity was related to study dropout. We discuss the results in terms of possible neurobiological causes underlying separable aging-related declines in inferior parietal cortex and lateral prefrontal cortex that differentially affect WM functions.

  • 175. Rypma, Bart
    et al.
    Fischer, Håkan
    Rieckmann, Anna
    Hubbard, Nicholas A
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB). Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Bäckman, Lars
    Dopamine D1 Binding Potential Predicts Fusiform BOLD Activity during Face-Recognition Performance2015Inngår i: Journal of Neuroscience, ISSN 0270-6474, E-ISSN 1529-2401, Vol. 35, nr 44, s. 14702-14707Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The importance of face memory in humans and primates is well established, but little is known about the neurotransmitter systems involved in face recognition. We tested the hypothesis that face recognition is linked to dopamine (DA) activity in fusiform gyrus (FFG). DA availability was assessed by measuring D1 binding potential (BP) during rest using PET. We further assessed blood-oxygen-level-dependent (BOLD) signal change while subjects performed a face-recognition task during fMRI scanning. There was a strong association between D1 BP and BOLD activity in FFG, whereas D1 BP in striatal and other extrastriatal regions were unrelated to neural activity in FFG. These results suggest that D1 BP locally modulates FFG function during face recognition. Observed relationships among D1 BP, BOLD activity, and face-recognition performance further suggest that D1 receptors place constraints on the responsiveness of FFG neurons.

    SIGNIFICANCE STATEMENT: The importance of face memory in humans and primates is well established, but little is known about the neurotransmitter systems involved in face recognition. Our work shows a role for a specific neurotransmitter system in face memory.

  • 176.
    Rönnlund, Michael
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Sundström, Anna
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi. Umeå universitet, Samhällsvetenskapliga fakulteten, Enheten för demografi och åldrandeforskning (CEDAR).
    Adolfsson, Rolf
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Psykiatri.
    Nilsson, Lars-Göran
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Aging Research Center, Karolinska Institutet, Stockholm, Sweden.
    Self-reported memory failures: associations with future dementia in a population-based study with long-term follow-up2015Inngår i: Journal of The American Geriatrics Society, ISSN 0002-8614, E-ISSN 1532-5415, Vol. 63, nr 9, s. 1766-1773Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    OBJECTIVES: To examine the association between self-reported memory failures and incident dementia in individuals aged 60 and older.

    DESIGN: Longitudinal, community based.

    SETTING: Betula Prospective Cohort Study, a population-based study in Umea, Sweden.

    PARTICIPANTS: Individuals with a mean age of 71.5 +/- 8.8 (range 60-90) (N = 1,547).

    MEASUREMENTS: Participants rated the frequency of everyday memory failures using the 16-item Prospective and Retrospective Memory Questionnaire (PRMQ) and underwent objective memory testing at baseline. Participant self-reports of complaints of poor memory by family and friends were evaluated. Dementia status was followed-up for 10 to 12 years.

    RESULTS: Over the study period, 225 participants developed dementia (132 with Alzheimer's disease (AD)). In Cox proportional hazard regression models adjusted for demographic factors, PRMQ z-scores predicted incident dementia (hazard ratio (HR) = 1.21 for all-cause dementia; HR = 1.25 for AD, Ps < .01). The significant associations remained when depressive symptoms and objective memory performance were adjusted for, when low performers on objective memory (= 1 standard deviations below the age group mean) were excluded, and in analyses with delayed entry (survival time = 5 years). Similar patterns were observed for the prospective and retrospective subscales, although including how often participants self-reported that others complained about their poor memory eliminated the association between PRMQ scores and dementia and itself emerged as a significant predictor.

    CONCLUSION: Self-reported memory failure predicted future dementia or AD independent of objective memory performance. Subjective reports of complaints by family and friends appear to be an even more-important indicator of preclinical impairments, and physicians should not ignore them, even in the absence of objective memory deficits.

  • 177.
    Rönnlund, Michael
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Sundström, Anna
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi. Umeå universitet, Samhällsvetenskapliga fakulteten, Enheten för demografi och åldrandeforskning (CEDAR).
    Adolfsson, Rolf
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Psykiatri.
    Nilsson, Lars-Göran
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Aging Research Center, Karolinska Institutet, Stockholm, Sweden.
    Subjective memory impairment in older adults predicts future dementia independent of baseline memory performance: Evidence from the Betula prospective cohort study2015Inngår i: Alzheimer's & Dementia, ISSN 1552-5260, E-ISSN 1552-5279, Vol. 11, nr 11, s. 1385-1392Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    INTRODUCTION: The objective was to examine whether subjective memory impairment (SMI) predicts all-cause dementia or Alzheimer's disease (AD) in a population-based study with long-term follow-up (median = 10 years).

    METHODS: A total of 2043 initially dementia-free participants (≥ 60 years) made three memory ratings ("compared with others", "compared with five years ago", and "complaints from family/friends") at baseline. During follow-up, 372 participants developed dementia (208 with AD).

    RESULTS: Cox regression revealed that subjective memory impairment ratings predicted all-cause dementia in models adjusting for age and sex (hazard ratio or HR from 2.04 to 3.94), with even higher values for AD (HR from 2.29 to 5.74). The result persisted in models including other covariates, including baseline episodic memory performance, and in analyses restricted to participants with long time to dementia diagnosis (≥ 5 years).

    DISCUSSION: The findings underscore the usefulness of subjective memory assessment in combination with other factors in identifying individuals at risk for developing dementia.

  • 178.
    Rönnlund, Michael
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Sundström, Anna
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi. Umeå universitet, Samhällsvetenskapliga fakulteten, Enheten för demografi och åldrandeforskning (CEDAR).
    Nilsson, Lars-Göran
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Aging Research Center, Karolinska Institutet, Sweden.
    Interindividual differences in general cognitive ability from age 18 to age 65 years are extremely stable and strongly associated with working memory capacity2015Inngår i: Intelligence, ISSN 0160-2896, E-ISSN 1873-7935, Vol. 53, s. 59-64Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The objective of the study was to examine the degree of stability of interindividual differences in general cognitive ability (g) across the adult life span. To this end, we examined a sample of men (n = 262), cognitively assessed for the first time at age 18 (conscript data). The sample was reassessed at age 50 and at five year intervals up to age 65. Scores from conscript tests at age 18 were retrieved and three of the subtests were used as indicators of g in early adulthood. At age 50–65 years, four indicators served the same purpose. At the 15-year follow-up (age 65) two working memory measures were administered which allowed examination of the relationship with working memory capacity. Results from structural Equation Modelling (SEM) indicated extremely high level of stability from young adulthood to age 50 (standardized regression coefficient = − 95) as well as from age 50 to age 55, 60 and 65 with stability coefficients of .90 or higher for the for the latent g factor. Standardized regression coefficients between young-adult g and the g factor in midlife/old age were .95 from age 18 up to age 50 and 55, .94 up to age 60, and .86 up to age 65. Hence, g at age 18 accounted for 90–74% of the variance in g 32–47 years later. A close association between g and working memory capacity was observed (concurrent association: r = .88, time lagged association: r = .61). Taken together, the present study demonstrates that interindividual differences in g are extremely stable over the period from 18 to midlife, with a significant deviation from unity only at age 65. In light of the parieto-frontal integration theory (P-FIT) of intelligence, consistent with the close association between g and working memory capacity, midlife may be characterized by neural stability, with decline and decreased interindividual stability, related to loss of parieto-frontal integrity, past age 60.

  • 179.
    Rönnlund, Michael
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Sundström, Anna
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi. Umeå universitet, Samhällsvetenskapliga fakulteten, Enheten för demografi och åldrandeforskning (CEDAR).
    Pudas, Sara
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Midlife level and 15-year changes in general cognitive ability in a sample of men: the role of education, early adult ability, BMI, and pulse pressure2017Inngår i: Intelligence, ISSN 0160-2896, E-ISSN 1873-7935, Vol. 61, s. 78-84Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The objective of the study was to examine determinants of midlife level and long-term changes in a general cog-nitive ability (g) factor. The data were from a Swedish sample of men (n=262;M=49.9years,SD=4.0)forwhich cognitive (conscript) test scores at age 18 were retrieved. In midlife the men completed a battery of cog-nitive tests that was re-administered atfive-year intervals up to 15 years after the baseline assessment. Second-order latent growth curve models were used to examine predictors of midlife level and longitudinal changes in agfactor reflecting four cognitive measures (WAIS-R Block Design, vocabulary, action recall, and wordfluency).The results showed education (years of schooling) to be related to ability level (intercept) before (β= 0.71),but not after (β= 0.09), adjustment of an early adult (age 18)gfactor (reflecting three different cognitive mea-sures)that washighly predictive of midlifeglevel (adjustedβ= 0.89). Neither education norgat age 18 (or mid-lifeglevel) was related to long-term changes ing, though. Conversely,baseline age, BMI, and pulse pressure wereunrelated to midlife ability level, but higher baseline age, higher BMI and higher pulse pressure in midlife werepredictive of cognitive decline. Thus, whereas higher levels of initial ability or educational attainment do not ap-pear to buffer against onset of age-related decline ingin midlife and young-old age, maintenance of lower levelsof pulse pressure and body weight could possibly have such an effect. However, further research is required toevaluate the mechanisms behind the observed relationships of the targeted variables and cognitive decline.

  • 180.
    Rönnlund, Michael
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Vestergren, Peter
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå forskningscentrum för matematikdidaktik (UFM). Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Stenling, Andreas
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Nilsson, Lars-Göran
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Aging Research Center, Karolinska Institutet, Sweden.
    Bergdahl, Maud
    Bergdahl, Jan
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi. Department of Clinical Dentistry, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway.
    Dimensionality of stress experiences: Factorial structure of the Perceived Stress Questionnaire (PSQ) in a population-based Swedish sample2015Inngår i: Scandinavian Journal of Psychology, ISSN 0036-5564, E-ISSN 1467-9450, Vol. 56, nr 5, s. 592-598Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We investigated the factorial structure of the Perceived Stress Questionnaire (PSQ-recent; Levenstein, Prantera, Varvo et al., 1993) in a large (N = 1516; 35-95 years) population-based Swedish sample (Nilsson, Adolfsson, Backman et al., 2004; Nilsson, Backman, Erngrund et al., 1997). Exploratory principal components analysis (PCA) was conducted on a first, randomly drawn subsample (n = 506). Next, the model based on the PCA was tested in a second sample (n = 505). Finally, a third sample (n = 505) was used to cross-validate the model. Five components were extracted in the PCA (eigenvalue > 1) and labeled "Demands," "Worries/Tension," " Lack of joy," " Conflict," and " Fatigue," respectively. Twenty-one out of the 30 original PSQ items were retained in a confirmatory factor analysis (CFA) model that included the five (first-order) factors and, additionally, a general (second-order) stress factor, not considered in prior models. The model showed reasonable goodness of fit [chi(2)(184) = 511.2, p < 0.001; CFI = 0.904; RMSEA = 0.059; and SRMR = 0.063]. Multigroup confirmatory factor analyses supported the validity of the established model. The results are discussed in relation to prior investigations of the factorial structure of the PSQ.

  • 181.
    Rönnqvist, Louise
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Domellöf, Erik
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Johansson, Anna-Maria
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Riklund, Katrine
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Lindqvist, Thomas
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi.
    Birgander, Richard
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi.
    Long term effects of preterm births: associations between upper-limb kinematics, brain volumes and cognitive functions2014Inngår i: Congress Programme. 1st Clinical Movement Analysis Word Conference, 2014, s. 310-310Konferansepaper (Fagfellevurdert)
    Abstract [en]

    INTRODUCTION and AIM

    Studies of long-term outcomes linked to a preterm birth have generally found increasing amount of neurodevelopmental and cognitive disabilities and delays. Still, few have addressed the upper-limb performance by means of kinematic outcomes in associations with cognitive functions and brain volumes. Thus, the main aim of this study was to investigate such possible relationships within school age preterm born children and in relation to their gestational age (GA) at birth.

    PATIENTS/MATERIALS and METHODS

    The present study is part of a longitudinal, ongoing multidisciplinary project with the goal to discover possible long-term effects of a preterm birth. In this sub-study 7-9-years-old children born preterm (PT) without early sign of neuropathology (N= 24, Mean GW=32, range 22-35) in comparison to age matched term born children (N=31) was included. Kinematics was measured by ProReflex, 3D-registration during task specific, bi- and uni-manual upper-limb movement performance. Additionally, functional brain volumes were investigated by 3-Tesla (T) magnetic resonance imaging (MRI) and cognitive functions by the Wechsler Intelligence Scale for Children, 4th edition (WISC-IV).

    RESULTS

    Our preliminary results show significant poorer upper-limb kinematics with more segmented and longer movement paths in the PT-born children in comparison to the term born, this was particular evident for thus children born very- and extremely PT (<32 GA). In agreement with this finding, a decreased total brain volume and regional gray matter reduction were significantly correlated with more segmented arm and head movement trajectories, and with poorer general IQ outcomes, as well as with lower gestational ages.

    DISCUSSION and CONCLUSIONS

    The findings from the present study show that a preterm birth, and especially a very- and extremely preterm birth, may cause long-term effects on the development of neurophysiology mechanism involved in the goal-directed upper-limb movements. Additionally, it shows that the development of the neuro-motor mechanisms also are associated with both cognitive functions and the general brain development. Thus, indicating that a very preterm birth seemingly still give neuro-developmental related problems when at school age.

  • 182.
    Salami, Alireza
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB). Umeå universitet, Medicinska fakulteten, Wallenberg centrum för molekylär medicin vid Umeå universitet (WCMM). Aging Research Center, Karolinska Institutet and Stockholm University, Stockholm, Sweden.
    Avelar-Pereira, Barbara
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Garzon, Benjamin
    Sitnikov, Rouslan
    Kalpouzos, Gregoria
    Functional coherence of striatal resting-state networks is modulated by striatal iron content2018Inngår i: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 183, s. 495-503Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Resting-state spontaneous fluctuations have revealed individual differences in the functional architecture of brain networks. Previous research indicates that the striatal network shows alterations in neurological conditions but also in normal aging. However, the neurobiological mechanisms underlying individual differences in striatal resting-state networks (RSNs) have been less explored. One candidate that may account for individual differences in striatal spontaneous activity is the level of local iron accumulation. Excessive iron in the striatum has been linked to a loss of structural integrity and reduced brain activity during task performance in aging. Using independent component analysis in a sample of 42 younger and older adults, we examined whether higher striatal iron content, quantified using relaxometry, underlies individual differences in spontaneous fluctuations of RSNs in general, and of the striatum in particular. Higher striatal iron content was linked to lower spontaneous coherence within both caudate and putamen RSNs regardless of age. No such links were observed for other RSNs. Moreover, the number of connections between the putamen and other RSNs was negatively associated with iron content, suggesting that iron modulated the degree of cross-talk between the striatum and cerebral cortex. Importantly, these associations were primarily driven by the older group. Finally, a positive association was found between coherence in the putamen and motor performance, suggesting that this spontaneous activity is behaviorally meaningful. A follow-up mediation analysis also indicated that functional connectivity may mediate the link between striatal iron and motor performance. Our preliminary findings suggest that striatal iron potentially accounts for individual differences in spontaneous striatal fluctuations, and might be used as a locus of intervention.

  • 183.
    Salami, Alireza
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Eriksson, Johan
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Kompus, Kristiina
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi. Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi.
    Habib, Reza
    Southern Illinois University , Carbondale.
    Kauppi, Karolina
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi. Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi.
    Characterizing the neural correlates of modality-specific and modality-independent accessibility and availability signals in memory using partial-least squares2010Inngår i: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 52, nr 2, s. 686-698Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Previous studies have shown that information that currently cannot be retrieved but will be retrieved on a subsequent, more supported task (i.e. is available but not accessible) has a distinct neural signature compared with non-available information. For verbal paired-associates, an availability signal has been revealed in left middle temporal cortex, an area potentially involved in the storage of such information, raising the possibility that availability signals are expressed in modality-specific storage sites. In the present study subjects encoded pictures and sounds representing concrete objects. One day later, during fMRI scanning, a verbal cued-recall task was administrated followed by a post-scan recognition task. Items remembered on both tasks were classified as accessible; items not remembered on the first but on the second task were classified as available; and items not remembered on any of the tasks were classified as not available. Multivariate partial-least-squares analyses revealed a modality-independent accessibility network with dominant contributions of left inferior parietal cortex, left inferior frontal cortex, and left hippocampus. Additionally, a modality-specific availability network was identified which included increased activity in visual regions for available pictorial information and in auditory regions for available sound information. These findings show that availability in memory, at least in part, is characterized by systematic changes in brain activity in sensory regions whereas memory access reflects differential activity in a modality-independent, conceptual network, thus indicating qualitative differences between availability and accessibility in memory.

  • 184.
    Salami, Alireza
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Eriksson, Johan
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Nilsson, Lars-Göran
    Stockholm University.
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi. Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Age-related white matter microstructural differences partly mediate age-related decline in processing speed but not cognition2012Inngår i: Biochimica et Biophysica Acta, ISSN 0006-3002, E-ISSN 1878-2434, Vol. 1822, nr 3, s. 408-415Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aging is associated with declining cognitive performance as well as structural changes in brain gray and white matter (WM). The WM deterioration contributes to a disconnection among distributed brain networks and may thus mediate age-related cognitive decline. The present diffusion tensor imaging (DTI) study investigated age-related differences in WM microstructure and their relation to cognition (episodic memory, visuospatial processing, fluency, and speed) in a large group of healthy subjects (n=287) covering 6 decades of the human life span. Age related decreases in fractional anisotropy (FA) and increases in mean diffusivity (MD) were observed across the entire WM skeleton as well as in specific WM tracts, supporting the WM degeneration hypothesis. The anterior section of the corpus callosum was more susceptible to aging compared to the posterior section, lending support to the anterior-posterior gradient of WM integrity in the corpus callosum. Finally, and of critical interest, WM integrity differences were found to mediate age-related reductions in processing speed but no significant mediation was found for episodic memory, visuospatial ability, or fluency. These findings suggest that compromised WM integrity is not a major contributing factor to declining cognitive performance in normal aging. This article is part of a Special Issue entitled: Imaging Brain Aging and Neurodegenerative disease.

  • 185.
    Salami, Alireza
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Eriksson, Johan
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Opposing effects of aging on large-scale brain systems for memory encoding and cognitive control2012Inngår i: Journal of Neuroscience, ISSN 0270-6474, E-ISSN 1529-2401, Vol. 32, nr 31, s. 10749-10757Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Episodic memory declines with advancing age. Neuroimaging studies have associated such decline to age-related changes in general cognitive-control networks as well as to changes in process-specific encoding or retrieval networks. To assess the specific influence of aging on encoding and retrieval processes and associated brain systems, it is vital to dissociate encoding and retrieval from each other and from shared cognitive-control processes. We used multivariate partial-least-squares to analyze functional magnetic resonance imaging data from a large population-based sample (n = 292, 25-80 years). The participants performed a face-name paired-associates task and an active baseline task. The analysis revealed two significant network patterns. The first reflected a process-general encoding-retrieval network that included frontoparietal cortices and posterior hippocampus. The second pattern dissociated encoding and retrieval networks. The anterior hippocampus was differentially engaged during encoding. Brain scores, representing whole-brain integrated measures of how strongly an individual recruited a brain network, were correlated with cognitive performance and chronological age. The scores from the general cognitive-control network correlated negatively with episodic memory performance and positively with age. The encoding brain scores, which strongly reflected hippocampal functioning, correlated positively with episodic memory performance and negatively with age. Univariate analyses confirmed that bilateral hippocampus showed the most pronounced activity reduction in older age, and brain structure analyses found that the activity reduction partly related to hippocampus atrophy. Collectively, these findings suggest that age-related structural brain changes underlie age-related reductions in the efficient recruitment of a process-specific encoding network, which cascades into upregulated recruitment of a general cognitive-control network.

  • 186.
    Salami, Alireza
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Wallenberg centrum för molekylär medicin vid Umeå universitet (WCMM). Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB). Aging Research Center, Karolinska Institutet and Stockholm University, Sweden.
    Garrett, Douglas D.
    Wåhlin, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Rieckmann, Anna
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Papenberg, Goran
    Karalija, Nina
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi. Center for Lifespan Psychology, Max Planck Institute for Human Development, Berlin, Germany.
    Jonasson, Lars
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Andersson, Micael
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB). Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Axelsson, Jan
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Johansson, Jarkko
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Riklund, Katrine
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Lövdén, Martin
    Lindenberger, Ulman
    Bäckman, Lars
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB). Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Dopamine D2/3 Binding Potential Modulates Neural Signatures of Working Memory in a Load-Dependent Fashion.2019Inngår i: Journal of Neuroscience, ISSN 0270-6474, E-ISSN 1529-2401, Vol. 39, nr 3, s. 537-547Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Dopamine (DA) modulates corticostriatal connections. Studies in which imaging of the DA system is integrated with functional imaging during cognitive performance have yielded mixed findings. Some work has shown a link between striatal DA (measured by PET) and fMRI activations, whereas others have failed to observe such a relationship. One possible reason for these discrepant findings is differences in task demands, such that a more demanding task with greater prefrontal activations may yield a stronger association with DA. Moreover, a potential DA–BOLD association may be modulated by task performance. We studied 155 (104 normal-performing and 51 low-performing) healthy older adults (43% females) who underwent fMRI scanning while performing a working memory (WM) n-back task along with DA D2/3 PET assessment using [11C]raclopride. Using multivariate partial-least-squares analysis, we observed a significant pattern revealing positive associations of striatal as well as extrastriatal DA D2/3 receptors to BOLD response in the thalamo–striatal–cortical circuit, which supports WM functioning. Critically, the DA–BOLD association in normal-performing, but not low-performing, individuals was expressed in a load-dependent fashion, with stronger associations during 3-back than 1-/2-back conditions. Moreover, normal-performing adults expressing upregulated BOLD in response to increasing task demands showed a stronger DA–BOLD association during 3-back, whereas low-performing individuals expressed a stronger association during 2-back conditions. This pattern suggests a nonlinear DA–BOLD performance association, with the strongest link at the maximum capacity level. Together, our results suggest that DA may have a stronger impact on functional brain responses during more demanding cognitive tasks.

  • 187.
    Salami, Alireza
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Karolinska Inst, Aging Res Ctr, S-11330 Stockholm, Sweden; Stockholm Univ, S-11330 Stockholm, Sweden.
    Pudas, Sara
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Elevated hippocampal resting-state connectivity underlies deficient neurocognitive function in aging2014Inngår i: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 111, nr 49, s. 17654-17659Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The brain is not idle during rest. Functional MRI (fMRI) studies have identified several resting-state networks, including the default mode network (DMN), which contains a set of cortical regions that interact with a hippocampus (HC) subsystem. Age-related alterations in the functional architecture of the DMN and HC may influence memory functions and possibly constitute a sensitive biomarker of forthcoming memory deficits. However, the exact form of DMN-HC alterations in aging and concomitant memory deficits is largely unknown. Here, using both task and resting data from 339 participants (25-80 y old), we have demonstrated age-related decrements in resting-state functional connectivity across most parts of the DMN, except for the HC network for which age-related elevation of connectivity between left and right HC was found along with attenuated HC-cortical connectivity. Elevated HC connectivity at rest, which was partly accounted for by age-related decline in white matter integrity of the fornix, was associated with lower cross-sectional episodic memory performance and declining longitudinal memory performance over 20 y. Additionally, elevated HC connectivity at rest was associated with reduced HC neural recruitment and HC-cortical connectivity during active memory encoding, which suggests that strong HC connectivity restricts the degree to which the HC interacts with other brain regions during active memory processing revealed by task fMRI. Collectively, our findings suggest a model in which age-related disruption in cortico-hippocampal functional connectivity leads to a more functionally isolated HC at rest, which translates into aberrant hippocampal decoupling and deficits during mnemonic processing.

  • 188.
    Salami, Alireza
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Karolinska Inst, Aging Res Ctr, SE-11330 Stockholm, Sweden.
    Rieckmann, Anna
    Fischer, Håkan
    Bäckman, Lars
    A multivariate analysis of age-related differences in functional networks supporting conflict resolution2014Inngår i: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 86, s. 150-163Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Functional neuroimaging studies demonstrate age-related differences in recruitment of a large-scale attentional network during interference resolution, especially within dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC). These alterations in functional responses have been frequently observed despite equivalent task performance, suggesting age-related reallocation of neural resources, although direct evidence for a facilitating effect in aging is sparse. We used the multi-source interference task and multivariate partial-least-squares to investigate age-related differences in the neuronal signature of conflict resolution, and their behavioral implications in younger and older adults. There were interference-related increases in activity, involving fronto-parietal and basal ganglia networks that generalized across age. In addition an age-by-task interaction was observed within a distributed network, including DLPFC and ACC, with greater activity during interference in the old. Next, we combined brain-behavior and functional connectivity analyses to investigate whether compensatory brain changes were present in older adults, using DLPFC and ACC as regions of interest (i.e. seed regions). This analysis revealed two networks differentially related to performance across age groups. A structural analysis revealed age-related gray-matter losses in regions facilitating performance in the young, suggesting that functional reorganization may partly reflect structural alterations in aging. Collectively, these findings suggest that age-related structural changes contribute to reductions in the efficient recruitment of a youth-like interference network, which cascades into instantiation of a different network facilitating conflict resolution in elderly people.

  • 189.
    Salami, Alireza
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Aging Research Center, Karolinska Institutet and Stockholm University, Stockholm, Sweden.
    Rieckmann, Anna
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Karalija, Nina
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi.
    Avelar-Pereira, Bárbara
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Aging Research Center, Karolinska Institutet and Stockholm University, Stockholm, Sweden.
    Andersson, Micael
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB). Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Wåhlin, Anders
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Papenberg, Goran
    Garrett, Douglas D.
    Riklund, Katrine
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Lövdén, Martin
    Lindenberger, Ulman
    Bäckman, Lars
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Neurocognitive Profiles of Older Adults with Working-Memory Dysfunction2018Inngår i: Cerebral Cortex, ISSN 1047-3211, E-ISSN 1460-2199, Vol. 28, nr 7, s. 2525-2539Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Individuals differ in how they perceive, remember, and think. There is evidence for the existence of distinct subgroups that differ in cognitive performance within the older population. However, it is less clear how individual differences in cognition in old age are linked to differences in brain-based measures. We used latent-profile analysis on n-back working-memory (WM) performance to identify subgroups in a large sample of older adults (n = 181; age = 64-68 years). Our analysis identified one larger normal subgroup with higher performance (n = 113; 63%), and a second smaller subgroup (n = 55; 31%) with lower performance. The low-performing subgroup showed weaker load-dependent BOLD modulation and lower connectivity within the fronto-parietal network (FPN) as well as between FPN and striatum during n-back, along with lower FPN connectivity at rest. This group also exhibited lower FPN structural integrity, lower frontal dopamine D2 binding potential, inferior performance on offline WM tests, and a trend-level genetic predisposition for lower dopamine-system efficiency. By contrast, this group exhibited relatively intact episodic memory and associated brain measures (i.e., hippocampal volume, structural, and functional connectivity within the default-mode network). Collectively, these data provide converging evidence for the existence of a group of older adults with impaired WM functioning characterized by reduced cortico-striatal coupling and aberrant cortico-cortical integrity within FPN.

  • 190.
    Salami, Alireza
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Aging Research Center, Karolinska Institutet and Stockholm University, SE-113 30, Stockholm, Sweden.
    Wåhlin, Anders
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Kaboodvand, Neda
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Aging Research Center, Karolinska Institutet and Stockholm University, SE-113 30, Stockholm, Sweden.
    Lundquist, Anders
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi.
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi.
    Longitudinal Evidence for Dissociation of Anterior and Posterior MTL Resting-State Connectivity in Aging: Links to Perfusion and Memory2016Inngår i: Cerebral Cortex, ISSN 1047-3211, E-ISSN 1460-2199, Vol. 26, nr 10, s. 3953-3963Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Neuroimaging studies of spontaneous signal fluctuations as measured by resting-state functional magnetic resonance imaging have revealed age-related alterations in the functional architecture of brain networks. One such network is located in the medial temporal lobe (MTL), showing structural and functional variations along the anterior-posterior axis. Past cross-sectional studies of MTL functional connectivity (FC) have yielded discrepant findings, likely reflecting the fact that specific MTL subregions are differentially affected in aging. Here, using longitudinal resting-state data from 198 participants, we investigated 5-year changes in FC of the anterior and posterior MTL. We found an opposite pattern, such that the degree of FC within the anterior MTL declined after age 60, whereas elevated FC within the posterior MTL was observed along with attenuated posterior MTL-cortical connectivity. A significant negative change-change relation was observed between episodic-memory decline and elevated FC in the posterior MTL. Additional analyses revealed age-related cerebral blood flow (CBF) increases in posterior MTL at the follow-up session, along with a positive relation of elevated FC and CBF, suggesting that elevated FC is a metabolically demanding alteration. Collectively, our findings indicate that elevated FC in posterior MTL along with increased local perfusion is a sign of brain aging that underlie episodic-memory decline.

  • 191. Salmi, Juha
    et al.
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB). Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Laine, Matti
    Working memory training mostly engages general-purpose large-scale networks for learning2018Inngår i: Neuroscience and Biobehavioral Reviews, ISSN 0149-7634, E-ISSN 1873-7528, Vol. 93, s. 108-122Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    The present meta-analytic study examined brain activation changes following working memory (WM) training, a form of cognitive training that has attracted considerable interest. Comparisons with perceptual-motor (PM) learning revealed that WM training engages domain-general large-scale networks for learning encompassing the dorsal attention and salience networks, sensory areas, and striatum. Also the dynamics of the training-induced brain activation changes within these networks showed a high overlap between WM and PM training. The distinguishing feature for WM training was the consistent modulation of the dorso- and ventrolateral prefrontal cortex (DLPFC/VLPFC) activity. The strongest candidate for mediating transfer to similar untrained WM tasks was the frontostriatal system, showing higher striatal and VLPFC activations, and lower DLPFC activations after training. Modulation of transfer-related areas occurred mostly with longer training periods. Overall, our findings place WM training effects into a general perception-action cycle, where some modulations may depend on the specific cognitive demands of a training task.

  • 192.
    Schrauben, Eric
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. Wisconsin, USA.
    Wåhlin, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Department of Radiology, University of Wisconsin – Madison, Madison, Wisconsin, USA.
    Ambarki, Khalid
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Centrum för medicinsk teknik och fysik (CMTF).
    Spaak, Erik
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Malm, Jan
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap.
    Wieben, Oliver
    University of Wisconsin – Madison, Madison, Wisconsin, USA.
    Eklund, Anders
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Centrum för medicinsk teknik och fysik (CMTF). Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Fast 4D flow MRI intracranial segmentation and quantification in tortuous arteries2015Inngår i: Journal of Magnetic Resonance Imaging, ISSN 1053-1807, E-ISSN 1522-2586, Vol. 42, nr 5, s. 1458-1464Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    PurposeTo describe, validate, and implement a centerline processing scheme (CPS) for semiautomated segmentation and quantification in carotid siphons of healthy subjects. 4D flow MRI enables blood flow measurement in all major cerebral arteries with one scan. Clinical translational hurdles are time demanding postprocessing and user-dependence induced variability during analysis. Materials and MethodsA CPS for 4D flow data was developed to automatically separate cerebral artery trees. Flow parameters were quantified at planes along the centerline oriented perpendicular to the vessel path. At 3T, validation against 2D phase-contrast (PC) magnetic resonance imaging (MRI) and 4D flow manual processing was performed on an intracranial flow phantom for constant flow, while pulsatile flow validation was performed in the internal carotid artery (ICA) of 10 healthy volunteers. The CPS and 4D manual processing times were measured and compared. Flow and area measurements were also demonstrated along the length of the ICA siphon. ResultsPhantom measurements for area and flow were highly correlated between the CPS and 2D measurements (area: R=0.95, flow: R=0.94), while in vivo waveforms were highly correlated (R=0.93). Processing time was reduced by a factor of 4.6 compared with manual processing. Whole ICA measurements revealed a significantly decreased area in the most distal segment of the carotid siphon (P=0.0017), with flow unchanged (P=0.84). ConclusionThis study exhibits fast semiautomated analysis of intracranial 4D flow MRI. Internal consistency was shown through flow conservation along the tortuous ICA siphon, which is typically difficult to assess. J. Magn. Reson. Imaging 2015;42:1458-1464.

  • 193. Sherif, A. M.
    et al.
    Eriksson, E.
    Thorn, M.
    Vasko, Janos
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Öhberg, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi.
    Riklund, Katrine
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Ljungberg, Börje
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Urologi och andrologi.
    Sentinel node detection in renal cell carcinoma. A feasibility study2012Inngår i: European urology. Supplement, ISSN 1569-9056, E-ISSN 1878-1500, Vol. 11, nr 1, s. E927-U948Artikkel i tidsskrift (Annet vitenskapelig)
  • 194.
    Sigray, Pontus Plavén
    et al.
    Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
    Gustavsson, Petter
    Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
    Farde, Lars
    Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
    Borg, Jacqueline
    Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
    Stenkrona, Per
    Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Bäckman, Lars
    Aging Research Center, Karolinska Institutet, Sweden.
    Cervenka, Simon
    Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
    Dopamine D1 receptor availability is related to social behavior: a positron emission tomography study2014Inngår i: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 102, nr 2, s. 590-595Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Dysfunctional interpersonal behavior is thought to underlie a wide spectrum of psychiatric disorders; however, the neurobiological underpinnings of these behavioral disturbances are poorly understood. Previous molecular imaging studies have shown associations between striatal dopamine (DA) D2-receptor binding and interpersonal traits, such as social conformity. The objective of this study was to explore, for the first time, the role of DA D1-receptors (D1-R) in human interpersonal behavior. Twenty-three healthy subjects were examined using Positron Emission Tomography and the radioligand [11C]SCH23390, yielding D1-R binding potential values. Striatal D1-R binding was related to personality scales selected to specifically assess one dimension of interpersonal behavior, namely a combination of affiliation and dominance (i.e., the Social Desirability, Verbal Trait Aggression and Physical Trait Aggression scales from Swedish Universities Scales of Personality). An exploratory analysis was also performed for extrastriatal brain regions. D1-R binding potential values in limbic striatum (r=.52; p=.015), associative striatum (r=.55; p=.009), and sensorimotor striatum (r=.67; p=.001) were positively related to Social Desirability scores. D1-R binding potential in limbic striatum (r=-.51; p=.019) was negatively associated with Physical Trait Aggression scores. For extrastriatal regions, Social Desirability scores showed positive correlations in amygdala (r=.60; p=.006) and medial frontal cortex (r=.60; p=.004). This study provides further support for the role of DA function in the expression of disaffiliative and dominant traits. Specifically, D1-R availability may serve as a marker for interpersonal behavior in humans. Associations were demonstrated for the same dimension of interpersonal behavior as for D2-R, but in the opposite direction, suggesting that the two receptor subtypes are involved in the same behavioral processes, but with different functional roles.

  • 195.
    Sjöberg, Rickard L
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap. University Hospital of Northern Sweden, Department of Neurosurgery, Umeå, Sweden.
    Stålnacke, Mattias
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap.
    Andersson, Micael
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Eriksson, Johan
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi.
    The supplementary motor area syndrome and cognitive control2019Inngår i: Neuropsychologia, ISSN 0028-3932, E-ISSN 1873-3514, Vol. 129, s. 141-145Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Supplementary Motor Area (SMA)-syndrome is a transient disturbance of the ability to initiate voluntary motor and speech actions that will often occur immediately after neurosurgical resections in the dorsal superior frontal gyrus but will typically have disappeared after 3 months. The purpose of the present study was to investigate the extent to which this syndrome is associated with alterations in cognitive control. Five patients who were to different extents affected by the SMA-syndrome after surgery for WHO grade II gliomas in the left hemisphere, were tested with the color word interference (Stroop) test; the Bergen dichotic listening test and for letter and category verbal fluency before surgery, 1–2 days after surgery and approximately 3 months after surgery. Results suggest that the motor symptoms known as the SMA syndrome co-occur with pronounced deficits in cognitive control.

  • 196.
    Sjölie, Daniel
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Kalpouzos, Grégoria
    Aging Research Center (ARC), Karolinska Institute and Stockholm University, Stockholm, Sweden.
    Eriksson, Johan
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB). Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Capturing neural correlates of disrupted presence ina naturalistic virtual environment2013Rapport (Annet vitenskapelig)
    Abstract [en]

    The concept of presence is commonly related to whether or not a user feels, acts, and reacts as if he/she were in a real familiar environment when using a virtual reality (VR) application. Understanding the neural correlates of presence may provide a foundation for objective measurements of presence and important constraints for theoretical explanations of presence. Discussions about the neural basis for presence are relatively common, but brain imaging has rarely been applied to investigating this issue. Previous studies have focused on detecting average differences between conditions that correlate with differences in reported presence. In this study we focused on breaks in presence and associated periods of disrupted presence as an important complement to previous work. Specifically, we measured brain activity with functional magnetic resonance imaging (fMRI) during execution of an everyday task in a naturalistic virtual environment (VE). Time periods of disrupted presence were identified by subject reports indicating something strange in the current environment, interpreted as a violation of expectations related to the sense of presence. Disrupted presence was associated with increased activity in the frontopolar cortex (FPC), lateral occipito-temporal cortex (LOTC), the temporal poles (TP), and the posterior superior temporal cortex (pSTC). We relate these areas to integration of key aspects of a presence experience, relating the (changing) situation to management of task and goals (FPC), interpretation of visual input (LOTC), emotional evaluation of the context (TP) and possible interactions (pSTC). Modulation of the activity level in these brain areas is consistent with an interpretation of disrupted presence as a re-evaluation of key aspects of a subjective mental reality, updating the synchronization with the virtual environment as previous predictions fail. Such a subjective mental reality may also be related to a self-centered type of mentalization, providing a link to accounts of presence building on the self.

  • 197. Sneve, Markus H.
    et al.
    Grydeland, Hakon
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Bowles, Ben
    Amlien, Inge K.
    Langnes, Espen
    Walhovd, Kristine B.
    Fjell, Anders M.
    Mechanisms Underlying Encoding of Short-Lived Versus Durable Episodic Memories2015Inngår i: Journal of Neuroscience, ISSN 0270-6474, E-ISSN 1529-2401, Vol. 35, nr 13, s. 5202-5212Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We continuously encounter and process novel events in the surrounding world, but only some episodes will leave detailed memory traces that can be recollected after weeks and months. Here, our aim was to monitor brain activity during encoding of events that eventually transforms into long-term stable memories. Previous functional magnetic resonance imaging (fMRI) studies have shown that the degree of activation of different brain regions during encoding is predictive of later recollection success. However, most of these studies tested participants' memories the same day as encoding occurred, whereas several lines of research suggest that extended post-encoding processing is of crucial importance for long-term consolidation. Using fMRI, we tested whether the same encoding mechanisms are predictive of recollection success after hours as after a retention interval of several weeks. Seventy-eight participants were scanned during an associative encoding task and given a source memory test the same day or after similar to 6 weeks. We found a strong link between regional activity levels during encoding and recollection success over short time intervals. However, results further showed that durable source memories, i.e., events recollected after several weeks, were not simply the events associated with the highest activity levels at encoding. Rather, strong levels of connectivity between the right hippocampus and perceptual areas, as well as with parts of the self-referential default-mode network, seemed instrumental in establishing durable source memories. Thus, we argue that an initial intensity-based encoding is necessary for short-term encoding of events, whereas additional processes involving hippocampal-cortical communication aid transformation into stable long-term memories.

  • 198.
    Sommer, Marius
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Häger, Charlotte
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering.
    Boraxbekk, Carl-Johan
    Umeå universitet, Samhällsvetenskapliga fakulteten, Enheten för demografi och åldrandeforskning (CEDAR). Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital, Hvidovre, Denmark.
    Rönnqvist, Louise
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Timing Training in Female Soccer Players: Effects on Skilled Movement Performance and Brain Responses2018Inngår i: Frontiers in Human Neuroscience, ISSN 1662-5161, E-ISSN 1662-5161, Vol. 12, artikkel-id 311Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Although trainers and athletes consider “good timing skills” critical for optimal sport performance, little is known in regard to how sport-specific skills may benefit from timing training. Accordingly, this study investigated the effects of timing training on soccer skill performance and the associated changes in functional brain response in elite- and sub-elite female soccer players. Twenty-five players (mean age 19.5 years; active in the highest or second highest divisions in Sweden), were randomly assigned to either an experimental- or a control group. The experimental group (n = 12) was subjected to a 4-week program (12 sessions) of synchronized metronome training (SMT). We evaluated effects on accuracy and variability in a soccer cross-pass task. The associated brain response was captured by functional magnetic resonance imaging (fMRI) while watching videos with soccer-specific actions. SMT improved soccer cross-pass performance, with a significant increase in outcome accuracy, combined with a decrease in outcome variability. SMT further induced changes in the underlying brain response associated with observing a highly familiar soccer-specific action, denoted as decreased activation in the cerebellum post SMT. Finally, decreased cerebellar activation was associated with improved cross-pass performance and sensorimotor synchronization. These findings suggest a more efficient neural recruitment during action observation after SMT. To our knowledge, this is the first controlled study providing behavioral and neurophysiological evidence that timing training may positively influence soccer-skill, while strengthening the action-perception coupling via enhanced sensorimotor synchronization abilities, and thus influencing the underlying brain responses.

  • 199.
    Stillesjö, Sara
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB). Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Similarity-based processes in human multiple-cue judgment: evidence from brain imaging and cognitive modelling2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Background: We often make judgments that require the consideration of several sources of information. For example, a teacher that grades a student´s exam question often integrates multiple sources of information (cues: details provided in the answer) into a single criterion dimension (the grade). This is an example of a multiple-cue judgment: a continuous estimate based on multiple cues. One common idea in the literature is that people often utilize different memory representations during this kind of judgment process. People sometimes rely on rules, where they weigh the impact of different cues together in an additive linear way. At other times, people focus on the similarity between a probe and their experience of previous similar cases.  It has been proposed that similarity is an important organizing principle by which people make judgments, and that similarity always influence the judgment process to some degree. Behavioral methods with cognitive modelling (fitting cognitive models of rule-based and similarity-based processes to behavioral judgment data) have been used to test when people engage in either process, based on the classification of the better model fit. The brain networks that support human multiple-cue judgment could provide some answers to the role of similarity-based processes, but the existing knowledge on this topic is limited.  Here, I combined functional magnetic resonance imaging (fMRI), cognitive modelling and experimental methods to extend previous behavioral research, and I focused on the nature of similarity in human multiple-cue judgment. I explored how the two types of memory representations are represented in the brain, if rule-based and similarity-based processes are exclusively engaged or operate as an interplay during the judgment process, and tested if similarity-based processes are the default process in rule-based judgment. 

    Results: Study I investigated how the relationship between rule-based and similarity-based processes should be understood. The results revealed that a similarity-based process in the precuneus is shared between the two conditions: a key brain region for similarity-based processes is thus critical for human judgment. Study II further explored the precuneus role in similarity-based judgment learning, and demonstrated that the precuneus contribute to a mnemonic process related to storing and retrieving memory representations that are used for similarity comparison. Study III tested the influence of similarity-based processes in rule-based judgment when a learned rule could not be applied, and results suggested that similarity-based processes influenced rule-based behavior. 

    Conclusion: These findings converge to the idea that similarity-based processes are critical for human multiple-cue judgment. Specifically, a similarity-based process in the precuneus, presumably involved in storage and retrieval of memory representations that are used for similarity comparison, stands out as a novel contribution to the neuroscience of human multiple-cue judgment.

  • 200.
    Stillesjö, Sara
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB). Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Nilsson, Håkan
    Institutionen för psykologi, Uppsala Universitet.
    Karlsson Wirebring, Linnea
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Exemplar-effects in rule-based multiple-cue judgment under time pressureManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    The field of multiple-cue judgment focuses on the cognitive representations and processes involved in tasks where people need to integrate information across several cues into a judgment on a single criterion dimension. We present here an experimental approach to examine the influence of exemplar-based processes in human judgment, hypothesizing that a default exemplar-based process underlie judgment with emphasis on when cue-abstraction is discontinued. Using predictions from detailed cognitive models, we evaluate participants judgments on two tests with and without time pressure, after extensive learning with cue-abstraction. Results confirmed that participants were unable to use cue-abstraction under time pressure, but failed to confirm the expected shift to exemplar-based memory based on model fit on group level. Participants did however show typical behavioral markers for exemplar-based processes under time pressure, which emphasizes its likely contribution in the judgment process. Moreover, a large subsample of participants did show the expected shift to exemplar-based memory under time pressure. Nevertheless, the results provide novel insights to how exemplar-based processes influence cue-abstraction under time pressure, and open up for the idea of a default exemplar-based process in human judgment.

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