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  • 1.
    Becker, Nina
    et al.
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI). Max Planck Institute for Human Development, Germany.
    Laukka, Erika J.
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Kalpouzos, Gregoria
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Naveh-Benjamin, Moshe
    Bäckman, Lars
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Brehmer, Yvonne
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI). Max Planck Institute for Human Development, Germany.
    Structural brain correlates of associative memory in older adults2015In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 118, 146-153 p.Article in journal (Refereed)
    Abstract [en]

    Associative memory involves binding two or more items into a coherent memory episode. Relative to memory for single items, associative memory declines greatly in aging. However, older individuals vary substantially in their ability to memorize associative information. Although functional studies link associative memory to the medial temporal lobe (MTL) and prefrontal cortex (PFC), little is known about how volumetric differences in MTL and PFC might contribute to individual differences in associative memory. We investigated regional gray-matter volumes related to individual differences in associative memory in a sample of healthy older adults (n = 54; age = 60 years). To differentiate item from associative memory, participants intentionally learned face-scene picture pairs before performing a recognition task that included single faces, scenes, and face-scene pairs. Gray-matter volumes were analyzed using voxel-based morphometry region-of-interest (ROI) analyses. To examine volumetric differences specifically for associative memory, item memory was controlled for in the analyses. Behavioral results revealed large variability in associative memory that mainly originated from differences in false-alarm rates. Moreover, associative memory was independent of individuals' ability to remember single items. Older adults with better associative memory showed larger gray-matter volumes primarily in regions of the left and right lateral PFC. These findings provide evidence for the importance of PFC in intentional learning of associations, likely because of its involvement in organizational and strategic processes that distinguish older adults with good from those with poor associative memory.

  • 2.
    Bellander, Martin
    et al.
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Berggren, Rasmus
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Mårtensson, Johan
    Brehmer, Yvonne
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI). Max Planck Institute for Human Development, Germany.
    Wenger, Elisabeth
    Li, Tie-Qiang
    Bodammer, Nils C.
    Shing, Yee-Lee
    Werkle-Bergner, Markus
    Lövdén, Martin
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Behavioral correlates of changes in hippocampal gray matter structure during acquisition of foreign vocabulary2016In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 131, 205-213 p.Article in journal (Refereed)
    Abstract [en]

    Experience can affect human gray matter volume. The behavioral correlates of individual differences in such brain changes are not well understood. In a group of Swedish individuals studying Italian as a foreign language, we investigated associations among time spent studying, acquired vocabulary, baseline performance on memory tasks, and gray matter changes. As a way of studying episodic memory training, the language learning focused on acquiring foreign vocabulary and lasted for 10 weeks. T-1-weighted structural magnetic resonance imaging and cognitive testing were performed before and after the studies. Learning behavior was monitored via participants' use of a smartphone application dedicated to the study of vocabulary. A whole-brain analysis showed larger changes in gray matter structure of the right hippocampus in the experimental group (N = 33) compared to an active control group (N = 23). A first path analyses revealed that time spent studying rather than acquired knowledge significantly predicted change in gray matter structure. However, this association was not significant when adding performance on baseline memory measures into the model, instead only the participants' performance on a short-term memory task with highly similar distractors predicted the change. This measure may tap similar individual difference factors as those involved in gray matter plasticity of the hippocampus.

  • 3.
    Brehmer, Yvonne
    et al.
    Aging Research Center, Karolinska Institutet.
    Rieckmann, Anna
    Aging Research Center, Karolinska Institutet.
    Bellander, Martin
    Aging Research Center, Karolinska Institutet.
    Westerberg, Helena
    Aging Research Center, Karolinska Institutet.
    Fischer, Håkan
    Stockholm University, Faculty of Social Sciences, Department of Psychology.
    Bäckman, Lars
    Aging Research Center, Karolinska Institutet.
    Neural correlates of training-related working-memory gains in old age2011In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 58, no 4, 1110-1120 p.Article in journal (Refereed)
    Abstract [en]

    Working memory (WM) functioning declines in old age. Due to its impact on many higher-order cognitive functions, investigating whether training can modify WM performance has recently been of great interest. We examined the relationship between behavioral performance and neural activity following five weeks of intensive WM training in 23 healthy older adults (M = 63.7 years). 12 participants received adaptive training (i.e. individually adjusted task difficulty to bring individuals to their performance maximum), whereas the others served as active controls (i.e. fixed low-level practice). Brain activity was measured before and after training, using fMRI, while subjects performed a WM task under two difficulty conditions. Although there were no training-related changes in WM during scanning, neocortical brain activity decreased post training and these decreases were larger in the adaptive training group than in the controls under high WM load. This pattern suggests intervention-related increases in neural efficiency. Further, there were disproportionate gains in the adaptive training group in trained as well as in non-trained (i.e. attention, episodic memory) tasks assessed outside the scanner, indicating the efficacy of the training regimen. Critically, the degree of training-related changes in brain activity (i.e. neocortical decreases and subcortical increases) was related to the maximum gain score achieved during the intervention period. This relationship suggests that the decreased activity, but also specific activity increases, observed were functionally relevant.

  • 4.
    Brehmer, Yvonne
    et al.
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Rieckmann, Anna
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Bellander, Martin
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Westerberg, Helena
    Fischer, Håkan
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI). Stockholm University, Faculty of Social Sciences, Department of Psychology.
    Bäckman, Lars
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Neural correlates of training-related working-memory gains in old age2011In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 58, no 4, 1110-1120 p.Article in journal (Refereed)
    Abstract [en]

    Working memory (WM) functioning declines in old age. Due to its impact on many higher-order cognitive functions, investigating whether training can modify WM performance has recently been of great interest. We examined the relationship between behavioral performance and neural activity following five weeks of intensive WM training in 23 healthy older adults (M = 63.7 years). 12 participants received adaptive training (i.e. individually adjusted task difficulty to bring individuals to their performance maximum), whereas the others served as active controls (i.e. fixed low-level practice). Brain activity was measured before and after training, using fMRI, while subjects performed a WM task under two difficulty conditions. Although there were no training-related changes in WM during scanning, neocortical brain activity decreased post training and these decreases were larger in the adaptive training group than in the controls under high WM load. This pattern suggests intervention-related increases in neural efficiency. Further, there were disproportionate gains in the adaptive training group in trained as well as in non-trained (i.e. attention, episodic memory) tasks assessed outside the scanner, indicating the efficacy of the training regimen. Critically, the degree of training-related changes in brain activity (i.e. neocortical decreases and subcortical increases) was related to the maximum gain score achieved during the intervention period. This relationship suggests that the decreased activity, but also specific activity increases, observed were functionally relevant.

  • 5.
    Brehmer, Yvonne
    et al.
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI). Max Planck Institute for Human Development, Germany.
    Shing, Yee Lee
    Heekeren, Hauke R.
    Lindenberger, Ulman
    Bäckman, Lars
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Training-induced changes in subsequent-memory effects: No major differences among children, younger adults, and older adults2016In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 131, 214-225 p.Article in journal (Refereed)
    Abstract [en]

    The neural correlates of encoding mode, or the state of forming new memory episodes, have been found to change with age and mnemonic training. However, it is unclear whether neural correlates of encoding success, termed subsequent-memory (SM) effects, also differ by age and mnemonic skill. In a multi-session training study, we investigated whether SM effects are altered by instruction and training in a mnemonic skill, and whether such alterations differ among children, younger adults, and older adults. Before and after strategy training, fMRI data were collected while participants were memorizing word pairs. In all age groups, participants receiving training showed greater performance gains than control group participants. Analysis of task-relevant regions showed training-induced reductions in SM effects in left frontal regions. Reductions in SM effects largely generalized across age and primarily reflected greater training-induced activation increases for omissions than for remembered items, indicating that training resulted in more consistent use of the mnemonic strategy. The present results reveal no major age differences in SM effects in children, younger adults, and older adults.

  • 6.
    Burzynska, A Z
    et al.
    Max Planck Institute for Human Development,.
    Preuschhof, C
    Max Planck Institute for Human Development,.
    Bäckman, Lars
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Nyberg, L
    Department of Radiation Sciences (Diagnostic Radiology) and Integrative Medical Biology (Physiology Section), Umeå University,.
    Li, S-C
    Max Planck Institute for Human Development,.
    Lindenberger, U
    Max Planck Institute for Human Development,.
    Heekeren, H R
    Max Planck Institute for Human Development,.
    Age-related differences in white matter microstructure: region-specific patterns of diffusivity2010In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 49, no 3, 2104-2112 p.Article in journal (Refereed)
    Abstract [en]

    We collected MRI diffusion tensor imaging data from 80 younger (20-32 years) and 63 older (60-71 years) healthy adults. Tract-based spatial statistics (TBSS) analysis revealed that white matter integrity, as indicated by decreased fractional anisotropy (FA), was disrupted in numerous structures in older compared to younger adults. These regions displayed five distinct region-specific patterns of age-related differences in other diffusivity properties: (1) increases in both radial and mean diffusivity; (2) increases in radial diffusivity; (3) no differences in parameters other than FA; (4) a decrease in axial and an increase in radial diffusivity; and (5) a decrease in axial and mean diffusivity. These patterns suggest different biological underpinnings of age-related decline in FA, such as demyelination, Wallerian degeneration, gliosis, and severe fiber loss, and may represent stages in a cascade of age-related degeneration in white matter microstructure. This first simultaneous description of age-related differences in FA, mean, axial, and radial diffusivity requires histological and functional validation as well as analyses of intermediate age groups and longitudinal samples.

  • 7. Ebner, Natalie C.
    et al.
    Johnson, Matthew R.
    Rieckmann, Anna
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Durbin, Kelly A.
    Johnson, Marcia K.
    Fischer, Håkan
    Stockholm University, Faculty of Social Sciences, Department of Psychology. Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Processing own-age vs. other-age faces: Neuro-behavioral correlates and effects of emotion2013In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 78, 363-371 p.Article in journal (Refereed)
    Abstract [en]

    Age constitutes a salient feature of a face and signals group membership. There is evidence of greater attention to and better memory for own-age than other-age faces. However, little is known about the neural and behavioral mechanisms underlying processing differences for own-age vs. other-age faces. Even less is known about the impact of emotion expressed in faces on such own-age effects. Using fMRI, the present study examined brain activity while young and older adult participants identified expressions of neutral, happy, and angry young and older faces. Across facial expressions, medial prefrontal cortex, insula, and (for older participants) amygdala showed greater activity to own-age than other-age faces. These own-age effects in ventral medial prefrontal cortex and insula held for neutral and happy faces, but not for angry faces. This novel and intriguing finding suggests that processing of negative facial emotions under some conditions overrides age-of-face effects.

  • 8. Economides, M.
    et al.
    Guitart-Masip, M.
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI). University College London, United Kingdom.
    Kurth-Nelson, Z.
    Dolan, R. J.
    Arbitration between controlled and impulsive choices2015In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 109, 206-216 p.Article in journal (Refereed)
    Abstract [en]

    The impulse to act for immediate reward often conflicts with more deliberate evaluations that support long-term benefit. The neural architecture that negotiates this conflict remains unclear. One account proposes a single neural circuit that evaluates both immediate and delayed outcomes, while another outlines separate impulsive and patient systems that compete for behavioral control. Here we designed a task in which a complex payout structure divorces the immediate value of acting from the overall long-term value, within the same outcome modality. Using model-based fMRI in humans, we demonstrate separate neural representations of immediate and long-term values, with the former tracked in the anterior caudate (AC) and the latter in the ventromedial prefrontal cortex (vmPFC). Crucially, when subjects' choices were compatible with long-run consequences, value signals in AC were down-weighted and those in vmPFC were enhanced, while the opposite occurred when choice was impulsive. Thus, our data implicate a trade-off in value representation between AC and vmPFC as underlying controlled versus impulsive choice.

  • 9. Grandy, Thomas H.
    et al.
    Werkle-Bergner, Markus
    Chicherio, Christian
    Lövden, Martin
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Schmiedek, Florian
    Lindenberger, Ulman
    Individual alpha peak frequency is related to latent factors of general cognitive abilities2013In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 79, 10-18 p.Article in journal (Refereed)
    Abstract [en]

    Some eighty years after the discovery of the human electroencephalogram (EEG) and its dominant rhythm, alpha (similar to 10 Hz), the neurophysiological functions and behavioral correlates of alpha oscillations are still under debate. Similarly, the biological mechanisms contributing to the general factor of intelligence, or g, have been under scrutiny for decades. Individual alpha frequency (IAF), a trait-like parameter of the EEG, has been found to correlate with individual differences in cognitive performance and cognitive abilities. Informed by large-scale theories of neural organization emphasizing the general functional significance of oscillatory activity, the present study replicates and extends these findings by testing the hypothesis that IAF is related to intelligence at the level of g, rather than at the level of specific cognitive abilities. Structural equation modeling allowed us to statistically control for measurement error when estimating the association between IAF and intellectual functioning. In line with our hypothesis, we found a statistically reliable and substantial correlation between IAF and g (r = .40). The magnitude of this correlation did not differ significantly between younger and older adults, and captured all of the covariation between IAF and the cognitive abilities of reasoning, memory, and perceptual speed. The observed association between IAF and g provides a parsimonious explanation for the commonly observed diffuse pattern of correlations between IAF and cognitive performance. We conclude that IAF is a marker of global architectural and functional properties of the human brain.

  • 10. Iannilli, Emilia
    et al.
    Wiens, Stefan
    Stockholm University, Faculty of Social Sciences, Department of Psychology.
    Arshamian, Artin
    Stockholm University, Faculty of Social Sciences, Department of Psychology.
    Seo, Han-Seok
    A spatiotemporal comparison between olfactory and trigeminal event-related potentials2013In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 77, 254-261 p.Article in journal (Refereed)
    Abstract [en]

    The present study compared the temporal and spatial aspects of human olfactory and trigeminal processing. A relatively selective trigeminal stimulus, CO2, and a relatively selective olfactory stimulus, H2S, were delivered with an olfactometer to young, healthy volunteers. The analysis was performed in a classical (5-electrode, main ERPs peaks) and modern approach (high topographical resolution, inverse solution, source localization). Results of microstate segmentation highlighted 5 maps that generally described the two processes at cerebral level. The trigeminal response differed from the olfactory response up to 300 ms after stimulus onset. In this time range, source analysis pointed out that the olfactory stimulation involved olfactory related areas, while trigeminal stimulation involved noxious/somatosensoiy specific brain areas. Moreover, from 300 ms on our data showed a similarity between the two processes. Statistical parametrical mapping of the differences between conditions suggested greater activation in a specific motor/sniffing network for the CO2 stimulation (probably related to a regulation of the potential noxious stimulus) and a greater activation of the ipsilateral primary olfactory cortex for H2S.

  • 11.
    Ingre, Michael
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Why small low-powered studies are worse than large high-powered studies and how to protect against "trivial" findings in research: comment on Friston (2012)2013In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 81, 496-498 p.Article in journal (Refereed)
    Abstract [en]

    It is sometimes argued that small studies provide better evidence for reported effects because they are less likely to report findings with small and trivial effect sizes (Friston, 2012). But larger studies are actually better at protecting against inferences from trivial effect sizes, if researchers just make use of effect sizes and confidence intervals. Poor statistical power also comes at a cost of inflated proportion of false positive findings, less power to "confirm" true effects and bias in reported (inflated) effect sizes. Small studies (n=16) lack the precision to reliably distinguish small and medium to large effect sizes (r<.50) from random noise (α=.05) that larger studies (n=100) does with high level of confidence (r=.50, p=.00000012). The present paper presents the arguments needed for researchers to refute the claim that small low-powered studies have a higher degree of scientific evidence than large high-powered studies.

  • 12. Jonasson, Lars S.
    et al.
    Axelsson, Jan
    Riklund, Katrine
    Braver, Todd S.
    Ogren, Mattias
    Bäckman, Lars
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Nyberg, Lars
    Dopamine release in nucleus accumbens during rewarded task switching measured by [C-11]raclopride2014In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 99, 357-364 p.Article in journal (Refereed)
    Abstract [en]

    Reward and motivation have positive influences on cognitive-control processes in numerous settings. Models of reward implicate corticostriatal loops and the dopamine (DA) system, with special emphasis on D-2 receptors in nucleus accumbens (NAcc). In this study, 11 right-handed males (35-40 years) were scanned with positron emission tomography (PET) in a single [C-11]raclopride dynamic scan during rewarded and non-rewarded task switching. Rewarded task switching (relative to baseline task switching) decreased [11C]raclopride binding in NAcc. Decreasing NAcc [C-11]raclopride binding was strongly associated with task reaction time measures that reflect individual differences in effort and control strategies. Voxelwise analyses additionally revealed reward-related DA release in anterodorsal caudate, a region previously associated with task-switching. These PET findings provide evidence for striatal DA release during motivated cognitive control, and further suggest that NAcc DA release predicts the task reaction time benefits of reward incentives.

  • 13. Jovanovic, H.
    et al.
    Perski, Aleksander
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Berglund, H.
    Savic, I.
    Chronic stress is linked to 5-HT(1A) receptor changes and functional disintegration of the limbic networks.2011In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 55, no 3, 1178-88 p.Article in journal (Refereed)
    Abstract [en]

    There are increasing reports about stress related cognitive and psychic declines in subjects who have no psychiatric premorbidity, depression, or major life trauma. Yet, little is known about the underlying neurobiology. Based on the typical symptomatology, fMRI data suggesting that stress activates the limbic circuits, and animal data showing a major involvement of the 5-HT(1A) receptor in stress regulation, we hypothesized that enduring daily stress causes widespread limbic dysfunctions, and specific changes of the 5-HT(1A) receptor. To test these hypotheses combined PET studies were carried out in 16 chronically stressed, and 16 non-stressed subjects. Limbic function was tested by measuring cerebral blood flow during rest, and when using an odor activation paradigm. 5-HT(1A) receptor binding potential (BP) was assessed with [(11)C]WAY100635. All subjects went through a battery of neuropsychological tests. Stressed subjects showed a functional disconnection between the amygdala and ACC/medial prefrontal cortex (mPFC), and an impaired odor activation of the ACC. They also displayed a reduced 5-HT(1A) receptor BP in the anterior cingulate (ACC), the insular-cortex, and the hippocampus. Their performance in attention-, odor discrimination-, and semantic memory tasks was impaired, and correlated with the BP-values in the respective region. The degree of reported stress was inversely correlated with activation of ACC, and the 5-HT(1A) receptor BP in the amygdala and hippocampus. Enduring every day psychosocial stress seems to be associated with a limbic reduction of 5-HT(1A) receptor binding and functional disintegration of ACC/mPFC. These changes support the notion of an impaired top-down regulation of stress stimuli, and identify potential targets for early treatment.

  • 14. Kauppi, Karolina
    et al.
    Nilsson, Lars-Göran
    Stockholm University, Faculty of Social Sciences, Department of Psychology. Stockholm Brain Institute, Sweden.
    Persson, Jonas
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Nyberg, Lars
    Additive genetic effect of APOE and BDNF on hippocampus activity2014In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 89, 306-313 p.Article in journal (Refereed)
    Abstract [en]

    Human memory is a highly heritable polygenic trait with complex inheritance patterns. To study the genetics of memory and memory-related diseases, hippocampal functioning has served as an intermediate phenotype. The importance of investigating gene-gene effects on complex phenotypes has been emphasized, but most imaging studies still focus on single polymorphisms. APOE epsilon 4 and BDNF Met, two of the most studied gene variants for variability in memory performance and neuropsychiatric disorders, have both separately been related to poorer episodic memory and altered hippocampal functioning. Here, we investigated the combined effect of APOE and BDNF on hippocampal activation (N = 151). No non-additive interaction effects were seen. Instead, the results revealed decreased activation in bilateral hippocampus and parahippocampus as a function of the number of APOE e4 and.BDNE Met alleles present (neither, one, or both). The combined effect was stronger than either of the individual effects, and both gene variables explained significant proportions of variance in BOLD signal change. Thus, there was an additive gene-gene effect of APOE and BDNF on medial temporal lobe (MTL) activation, showing that a larger proportion of variance in brain activation attributed to genetics can be explained by considering more than one gene variant This effect might be relevant for the understanding of normal variability in memory function as well as memory-related disorders associated with APOE and BDNF.

  • 15.
    Lundqvist, Mikael
    et al.
    Stockholm University, Faculty of Science, Numerical Analysis and Computer Science (NADA). Royal Institute of Technology, Sweden.
    Herman, Pawel
    Stockholm University, Faculty of Science, Numerical Analysis and Computer Science (NADA). Royal Institute of Technology, Sweden.
    Palva, M.
    Palva, S.
    Silverstein, David
    Stockholm University, Faculty of Science, Numerical Analysis and Computer Science (NADA). Royal Institute of Technology, Sweden.
    Lansner, Anders
    Stockholm University, Faculty of Science, Numerical Analysis and Computer Science (NADA). Royal Institute of Technology, Sweden.
    Stimulus detection rate and latency, firing rates and 1-40Hz oscillatory power are modulated by infra-slow fluctuations in a bistable attractor network model2013In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 83, 458-471 p.Article in journal (Refereed)
    Abstract [en]

    Recordings of membrane and field potentials, firing rates, and oscillation amplitude dynamics show that neuronal activity levels in cortical and subcortical structures exhibit infra-slow fluctuations (ISFs) on time scales from seconds to hundreds of seconds. Similar ISFs are salient also in blood-oxygenation-level dependent (BOLD) signals as well as in psychophysical time series. Functional consequences of ISFs are not fully understood. Here, they were investigated along with dynamical implications of ISFs in large-scale simulations of cortical network activity. For this purpose, a biophysically detailed hierarchical attractor network model displaying bistability and operating in an oscillatory regime was used. ISFs were imposed as slow fluctuations in either the amplitude or frequency of fast synaptic noise. We found that both mechanisms produced an ISF component in the synthetic local field potentials (LFPs) and modulated the power of 1-40. Hz oscillations. Crucially, in a simulated threshold-stimulus detection task (TSDT), these ISFs were strongly correlated with stimulus detection probabilities and latencies. The results thus show that several phenomena observed in many empirical studies emerge concurrently in the model dynamics, which yields mechanistic insight into how infra-slow excitability fluctuations in large-scale neuronal networks may modulate fast oscillations and perceptual processing. The model also makes several novel predictions that can be experimentally tested in future studies.

  • 16.
    Lövdén, Martin
    et al.
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI). Max Planck Society, Germany.
    Kohncke, Ylva
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Laukka, Erika J.
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Kalpouzos, Gregoria
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Salami, Alireza
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI). Umeå Center for Functional Brain Imaging, Sweden.
    Li, Tie-Qiang
    Fratiglioni, Laura
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI). Stockholm Gerontology Research Center, Sweden.
    Bäckman, Lars
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Changes in perceptual speed and white matter microstructure in the corticospinal tract are associated in very old age2014In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 102, 520-530 p.Article in journal (Refereed)
    Abstract [en]

    The integrity of the brain's white matter is important for neural processing and displays age-related differences, but the contribution of changes in white matter to cognitive aging is unclear. We used latent change modeling to investigate this issue in a sample of very old adults (aged 81-103 years) assessed twice with a retest interval of 2.3 years. Using diffusion-tensor imaging, we probed white matter microstructure by quantifying mean fractional anisotropy and mean diffusivity of six major white matter tracts. Measures of perceptual speed, episodic memory, letter fluency, category fluency, and semantic memory were collected. Across time, alterations of white matter microstructure in the corticospinal tract were associated with decreases of perceptual speed. This association remained significant after statistically controlling for changes in white matter microstructure in the entire brain, in the other demarcated tracts, and in the other cognitive abilities. Changes in brain volume also did not account for the association. We conclude that white matter microstructure is a potent correlate of changes in sensorimotor aspects of behavior in very old age, but that it is unclear whether its impact extends to higher-order cognition.

  • 17.
    Lövdén, Martin
    et al.
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Schmiedek, Florian
    Kennedy, Kristen M.
    Rodrigue, Karen M.
    Lindenberger, Ulman
    Raz, Naftali
    Does variability in cognitive performance correlate with frontal brain volume?2013In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 64, 209-15 p.Article in journal (Refereed)
    Abstract [en]

    Little is known about the neural correlates of within-person variability in cognitive performance. We investigated associations between regional brain volumes and trial-to-trial, block-to-block, and day-to-day variability in choice-reaction time, and episodic and working memory accuracy. Healthy younger (n=25) and older (n=18) adults underwent 101 daily assessments of cognitive performance, and their regional brain volumes were measured manually on magnetic resonance images. Results showed that smaller prefrontal white matter volumes were associated with higher block-to-block variability in choice-reaction time performance, with a stronger association observed among older adults. Smaller volumes of the dorsolateral prefrontal cortex covaried with higher block-to-block variability in episodic memory (number-word pair) performance. This association was stronger for younger adults. The observed associations between variability and brain volume were not due to individual differences in mean performance. Trial-to-trial and day-to-day variability in cognitive performance were unrelated to regional brain volume. We thus report novel findings demonstrating that block-by-block variability in cognitive performance is associated with integrity of the prefrontal regions and that between-person differences in different measures of variability of cognitive performance reflect different age-related constellations of behavioral and neural antecedents.

  • 18. Maass, Anne
    et al.
    Düzel, Sandra
    Brigadski, Tanja
    Goerke, Monique
    Becke, Andreas
    Sobieray, Uwe
    Neumann, Katja
    Lövdén, Martin
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI). Max Planck Institute for Human Development, Germany.
    Lindenberger, Ulman
    Bäckman, Lars
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Braun-Dullaeus, Rüdiger
    Ahrens, Dörte
    Heinze, Hans-Jochen
    Müller, Notger G.
    Lessmann, Volkmar
    Sendtner, Michael
    Düzel, Emrah
    Relationships of peripheral IGF-1, VEGF and BDNF levels to exercise-related changes in memory, hippocampal perfusion and volumes in older adults2016In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 131, 142-154 p.Article in journal (Refereed)
    Abstract [en]

    Animal models point towards a key role of brain-derived neurotrophic factor (BDNF), insulin-like growth factor-I (IGF-I) and vascular endothelial growth factor (VEGF) in mediating exercise-induced structural and functional changes in the hippocampus. Recently, also platelet derived growth factor-C (PDGF-C) has been shown to promote blood vessel growth and neuronal survival. Moreover, reductions of these neurotrophic and angiogenic factors in old age have been related to hippocampal atrophy, decreased vascularization and cognitive decline. In a 3-month aerobic exercise study, forty healthy older humans (60 to 77 years) were pseudo-randomly assigned to either an aerobic exercise group (indoor treadmill, n=21) or to a control group (indoor progressive-muscle relaxation/stretching, n=19). As reported recently, we found evidence for fitness-related perfusion changes of the aged human hippocampus that were closely linked to changes in episodic memory function. Here, we test whether peripheral levels of BDNF, IGF-I, VEGF or PDGF-C are related to changes in hippocampal blood flow, volume and memory performance. Growth factor levels were not significantly affected by exercise, and their changes were not related to changes in fitness or perfusion. However, changes in IGF-I levels were positively correlated with hippocampal volume changes (derived by manual volumetry and voxel-based morphometry) and late verbal recall performance, a relationship that seemed to be independent of fitness, perfusion or their changes over time. These preliminary findings link IGF-I levels to hippocampal volume changes and putatively hippocampus-dependent memory changes that seem to occur over time independently of exercise. We discuss methodological shortcomings of our study and potential differences in the temporal dynamics of how IGF-1, VEGF and BDNF may be affected by exercise and to what extent these differences may have led to the negative findings reported here.

  • 19.
    Marklund, Petter
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Psychology.
    Persson, Jonas
    Stockholm University, Faculty of Social Sciences, Department of Psychology. Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Context dependent switching between proactive and reactive working memory control mechanisms in the right inferior frontal gyrus2012In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 63, no 3, 1552-1560 p.Article in journal (Refereed)
    Abstract [en]

    A critical feature of higher cognitive functioning is the capacity to flexibly tailor information processing and behaviors to current situational demands. Recent neurocognitive models have been postulated to account for the dynamic nature of human executive processing by invoking two dissociable cognitive control modes, proactive and reactive control. These may involve partially overlapping, but temporally distinct neural implementation in the prefrontal cortex. Prior brain imaging studies exploring proactive control have mainly used tasks requiring only information about single-items to be retained over unfilled delays. Whether proactive control can also be utilized to facilitate performance in more complex working memory tasks, in which concurrent processing of intervening items and updating is mandatory during contextual cue maintenance remains an open question. To examine this issue and to elucidate the extent to which overlapping neural substrates underlie proactive and reactive control we used fMRI and a modified verbal 3-back paradigm with embedded cues predictive of high-interference trials. This task requires context information to be retained over multiple intervening trials. We found that performance improved with item-specific cues predicting forthcoming lures despite increased working memory load. Temporal dynamics of activation in the right inferior frontal gyrus suggest flexible switching between proactive and reactive control in a context-dependent fashion, with greater sustained responses elicited in the 3-back task involving context maintenance of cue information and greater transient responses elicited in the 3-back task absent of cues.

  • 20. Mårtensson, Johan
    et al.
    Eriksson, Johan
    Bodammer, Nils Christian
    Lindgren, Magnus
    Johansson, Mikael
    Nyberg, Lars
    Lövdén, Martin
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Growth of language-related brain areas after foreign language learning2012In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 63, no 1, 240-244 p.Article in journal (Refereed)
    Abstract [en]

    The influence of adult foreign-language acquisition on human brain organization is poorly understood. We studied cortical thickness and hippocampal volumes of conscript interpreters before and after three months of intense language studies. Results revealed increases in hippocampus volume and in cortical thickness of the left middle frontal gyrus, inferior frontal gyrus, and superior temporal gyrus for interpreters relative to controls. The right hippocampus and the left superior temporal gyrus were structurally more malleable in interpreters acquiring higher proficiency in the foreign language. Interpreters struggling relatively more to master the language displayed larger gray matter increases in the middle frontal gyrus. These findings confirm structural changes in brain regions known to serve language functions during foreign-language acquisition.

  • 21. Nyberg, Lars
    et al.
    Andersson, Micael
    Forsgren, Lars
    Jakobsson-Mo, Susanna
    Larsson, Anne
    Marklund, Petter
    Stockholm University, Faculty of Social Sciences, Department of Psychology. Stockholm Brain Institute, Sweden.
    Nilsson, Lars-Göran
    Stockholm University, Faculty of Social Sciences, Department of Psychology. Stockholm Brain Institute, Sweden.
    Riklund, Katrine
    Bäckman, Lars
    Striatal dopamine D2 binding is related to frontal BOLD response during updating of long-term memory representations2009In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 46, no 4, 1194-1199 p.Article in journal (Refereed)
    Abstract [en]

    Multi-modal brain imaging was used to examine the relation between individual differences in resting-state striatal dopamine D2 binding and the magnitude of prefrontal BOLD activation during updating of long-term memory (LTM) representations. Increased activity in the left prefrontal cortex was observed when LTM updating was required, and there was a positive correlation between striatal D2 activity and the magnitude of left prefrontal activity during updating. These findings support predictions from neurocomputational models of a relation of dopaminergic neurotransmission to transient cognitive operations and related brain activity.

  • 22.
    Peira, Nathalie
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Perception and psychophysics. Uppsala University, Sweden.
    Ziaei, Maryam
    Persson, Jonas
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI). Stockholm University, Faculty of Social Sciences, Department of Psychology, Cognitive psychology.
    Age differences in brain systems supporting transient and sustained processes involved in prospective memory and working memory2016In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 125, 745-755 p.Article in journal (Refereed)
    Abstract [en]

    In prospective memory (PM), an intention to act in response to an external event is formed, retained, and at a later stage, when the event occurs, the relevant action is performed. PM typically shows a decline in late adulthood, which might affect functions of daily living. The neural correlates of this decline are not well understood. Here, 15 young (6 female; age range = 23-30 years) and 16 older adults (5 female; age range = 64-74 years) were scanned with fMRI to examine age-related differences in brain activation associated with event-based PM using a task that facilitated the separation of transient and sustained components of PM. We show that older adults had reduced performance in conditions with high demands on prospective and working memory, while no age-difference was observed in low-demanding tasks. Across age groups, PM task performance activated separate sets of brain regions for transient and sustained responses. Age-differences in transient activation were found in fronto-striatal and MTL regions, with young adults showing more activation than older adults. Increased activation in young, compared to older adults, was also found for sustained PM activation in the IFG. These results provide new evidence that PM relies on dissociable transient and sustained cognitive processes, and that age-related deficits in PM can be explained by an inability to recruit PM-related brain networks in old age.

  • 23.
    Persson, Ninni
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Psychology. Stockholm Brain Institute, Sweden; Wayne State University, USA.
    Ghisletta, P.
    Dahle, C. L.
    Bender, A. R.
    Yang, Y.
    Yuan, P.
    Daugherty, A. M.
    Raz, N.
    Regional brain shrinkage over two years: Individual differences and effects of pro-inflammatory genetic polymorphisms2014In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 103, 334-348 p.Article in journal (Refereed)
    Abstract [en]

    We examined regional changes in brain volume in healthy adults (N = 167, age 19–79 years at baseline; N = 90 at follow-up) over approximately two years. With latent change score models, we evaluated mean change and individual differences in rates of change in 10 anatomically-defined and manually-traced regions of interest (ROIs): lateral prefrontal cortex (LPFC), orbital frontal cortex (OF), prefrontal white matter (PFw), hippocampus (Hc), parahippocampal gyrus (PhG), caudate nucleus (Cd), putamen (Pt), insula (In), cerebellar hemispheres (CbH), and primary visual cortex (VC). Significant mean shrinkage was observed in the Hc, CbH, In, OF, and PhG, and individual differences in change were noted in all regions, except the OF. Pro-inflammatory genetic variants modified shrinkage in PhG and CbH. Carriers of two T alleles of interleukin-1β (IL-1β C-511T, rs16944) and a T allele of methylenetetrahydrofolate reductase (MTHFR C677T, rs1801133) polymorphisms showed increased PhG shrinkage. No effects of a pro-inflammatory polymorphism for C-reactive protein (CRP-286C>A>T, rs3091244) or apolipoprotein (APOE) ε4 allele were noted. These results replicate the pattern of brain shrinkage observed in previous studies, with a notable exception of the LPFC, thus casting doubt on the unique importance of prefrontal cortex in aging. Larger baseline volumes of CbH and In were associated with increased shrinkage, in conflict with the brain reserve hypothesis. Contrary to previous reports, we observed no significant linear effects of age and hypertension on regional brain shrinkage. Our findings warrant further investigation of the effects of neuroinflammation on structural brain change throughout the lifespan.

  • 24.
    Persson, Ninni
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Biological psychology. Stockholm Brain Institute, Sweden.
    Ghisletta, Paolo
    Dahle, Cheryl L.
    Bender, Andrew R.
    Yang, Yiqin
    Yuan, Peng
    Daugherty, Ana M.
    Raz, Naftali
    Regional brain shrinkage and change in cognitive performance over two years: The bidirectional influences of the brain and cognitive reserve factors2016In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 126, 15-26 p.Article in journal (Refereed)
    Abstract [en]

    We examined relationships between regional brain shrinkage and changes in cognitive performance, while taking into account the influence of age, vascular risk, Apolipoprotein E variant and socioeconomic status. Regional brain volumes and cognitive performance were assessed in 167 healthy adults (age 19-79 at baseline), 90 of whom returned for the follow-up after two years. Brain volumes were measured in six regions of interest (ROIs): lateral prefrontal cortex (LPFC), prefrontal white matter (PFw), hippocampus (Hc), parahippocampal gyrus (PhG), cerebellar hemispheres (CbH), and primary visual cortex (VC), and cognitive performance was evaluated in three domains: episodic memory (EM), fluid intelligence (Gf), and vocabulary (V). Average volume loss was observed in Hc, PhG and CbH, but reliable individual differences were noted in all examined ROIs. Average positive change was observed in EM and V performance but not in Gf scores, yet only the last evidenced individual differences in change. We observed reciprocal influences among neuroanatomical and cognitive variables. Larger brain volumes at baseline predicted greater individual gains in Gf, but differences in LPFC volume change were in part explained by baseline level of cognitive performance. In one region (PFw), individual change in volume was coupled with change in Gf. Larger initial brain volumes did not predict slower shrinkage. The results underscore the complex role of brain maintenance and cognitive reserve in adult development.

  • 25.
    Persson, Ninni
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Psychology. Stockholm Brain Institute, Sweden; Weill Cornell Medical College, USA.
    Wu, Jianlin
    Zhang, Qing
    Liu, Ting
    Shen, Jing
    Bao, Ruyi
    Ni, Mingfei
    Liu, Tian
    Wang, Yi
    Spincemaille, Pascal
    Age and sex related differences in subcortical brain iron concentrations among healthy adults2015In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 122, 385-398 p.Article in journal (Refereed)
    Abstract [en]

    Age and sex can influence brain iron levels. We studied the influence of these variables on deep gray matter magnetic susceptibilities. In 183 healthy volunteers (44.7 ± 14.2 years, range 20–69, ♀ 49%), in vivo quantitative susceptibility mapping (QSM) at 1.5 T was performed to estimate brain iron accumulation in the following regions of interest (ROIs): caudate nucleus (Cd), putamen (Pt), globus pallidus (Gp), thalamus (Th), pulvinar (Pul), red nucleus (Rn), substantia nigra (Sn) and the cerebellar dentate nuclei (Dn). We gauged the influence of age and sex on magnetic susceptibility by specifying a series of structural equation models. The distributions of susceptibility varied in degree across the structures, conforming to histologic findings (Hallgren and Sourander, 1958), with the highest degree of susceptibility in the Gp and the lowest in the Th. Iron increase correlated across several ROIs, which may reflect an underlying age-related process. Advanced age was associated with a particularly strong linear rise of susceptibility in the striatum. Nonlinear age trends were found in the Rn, where they were the most pronounced, followed by the Pul and Sn, while minimal nonlinear trends were observed for the Pt, Th, and Dn. Moreover, sex related variations were observed, so that women showed lower levels of susceptibility in the Sn after accounting for age. Regional susceptibility of the Pul increased linearly with age in men but exhibited a nonlinear association with age in women with a leveling off starting from midlife. Women expected to be post menopause (+ 51 years) showed lower total magnetic susceptibility in the subcortical gray matter. The current report not only is consistent with previous reports of age related variations of brain iron, but also adds to the current knowledge by reporting age-related changes in less studied, smaller subcortical nuclei. This is the first in-vivo report to show lower total subcortical brain iron levels selectively in women from midlife, compared to men and younger women. These results encourage further assessment of sex differences in brain iron. We anticipate that age and sex are important co-factors to take into account when establishing a baseline level for differentiating pathologic neurodegeneration from healthy aging. The variations in regional susceptibility reported herein should be evaluated further using a longitudinal study design to determine within-person changes in aging.

  • 26. Plaven-Sigray, Pontus
    et al.
    Gustavsson, Petter
    Farde, Lars
    Borg, Jacqueline
    Stenkrona, Per
    Nyberg, Lars
    Bäckman, Lars
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Cervenka, Simon
    Dopamine D1 receptor availability is related to social behavior: A positron emission tomography study2014In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 102, 590-595 p.Article in journal (Refereed)
    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-Rs) in human interpersonal behavior. Twenty-three healthy subjects were examined using positron emission tomography and the radioligand [C-11] 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 the 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 the limbic striatum (r= -.51; p = .019) was negatively associated with Physical Trait Aggression scores. For extrastriatal regions, Social Desirability scores showed positive correlations in the 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.

  • 27.
    Rieckmann, Anna
    et al.
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Fischer, Håkan
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Bäckman, Lars
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Activation in striatum and medial temporal lobe during sequence learning in younger and older adults: relations to performance2010In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 50, no 3, 1303-1312 p.Article in journal (Refereed)
    Abstract [en]

    The striatum and connected cortical areas have been implicated in sequence learning (SL) tasks, in which performance increments are gradual and learning typically occurs in the absence of awareness. It has recently been shown that increasing striatal activation during SL may be accompanied by decreasing activation in the medial temporal lobe (MTL) across time, but the specific contribution of the MTL to SL remains unclear. In the current age-comparative fMRI study, we show that gradual SL in the serial reaction time task is associated with activation increases in the striatum and activation decreases in the MTL across time in younger adults. However, in older adults, SL is positively related to activation increases in both the striatum and the MTL. The results are discussed in terms of the functional role of the MTL in SL, and offer a novel explanation of the fact that SL is little affected in aging.

  • 28.
    Salami, Alireza
    et al.
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Rieckmann, Anna
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Fischer, Håkan
    Stockholm University, Faculty of Social Sciences, Department of Psychology.
    Bäckman, Lars
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    A Multivariate Analysis of Age-Related Differences in Functional Networks Supporting Conflict Resolution2014In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 86, 150-163 p.Article in journal (Refereed)
    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.

  • 29. Wenger, Elisabeth
    et al.
    Schaefer, Sabine
    Noack, Hannes
    Kühn, Simone
    Mårtensson, Johan
    Heinze, Hans-Jochen
    Düzel, Emrah
    Bäckman, Lars
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Lindenberger, Ulman
    Lövdén, Martin
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Cortical thickness changes following spatial navigation training in adulthood and aging2012In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 59, no 4, 3389-97 p.Article in journal (Refereed)
    Abstract [en]

    A widespread network involving cortical and subcortical brain structures forms the neural substrate of human spatial navigation. Most studies investigating plasticity of this network have focused on the hippocampus. Here, we investigate age differences in cortical thickness changes evoked by four months of spatial navigation training in 91 men aged 20-30 or 60-70 years. Cortical thickness was automatically measured before, immediately after, and four months after termination of training. Younger as well as older navigators evidenced large improvements in navigation performance that were partly maintained after termination of training. Importantly, training-related cortical thickening in left precuneus and paracentral lobule were observed in young navigators only. Thus, spatial navigation training appears to affect cortical brain structure of young adults, but there is reduced potential for experience-dependent cortical alterations in old age.

  • 30. Ziaei, Maryam
    et al.
    Peira, Nathalie
    Stockholm University, Faculty of Social Sciences, Department of Psychology. Uppsala Universitet.
    Persson, Jonas
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Brain systems underlying attentional control and emotional distraction during working memory encoding2014In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 87, 276-286 p.Article in journal (Refereed)
    Abstract [en]

    Goal-directed behavior requires that cognitive operations can be protected from emotional distraction induced by task-irrelevant emotional stimuli. The brain processes involved in attending to relevant information while filtering out irrelevant information are still largely unknown. To investigate the neural and behavioral underpinnings of attending to task-relevant emotional stimuli while ignoring irrelevant stimuli, we used fMRI to assess brain responses during attentional instructed encoding within an emotional working memory (WM) paradigm. We showed that instructed attention to emotion during WM encoding resulted in enhanced performance, by means of increased memory performance and reduced reaction time, compared to passive viewing. A similar performance benefit was also demonstrated for recognition memory performance, although for positive pictures only. Functional MRI data revealed a network of regions involved in directed attention to emotional information for both positive and negative pictures that included medial and lateral prefrontal cortices, fusiform gyrus, insula, the parahippocampal gyrus, and the amygdala. Moreover, we demonstrate that regions in the striatum, and regions associated with the default-mode network were differentially activated for emotional distraction compared to neutral distraction. Activation in a sub-set of these regions was related to individual differences in WM and recognition memory performance, thus likely contributing to performing the task at an optimal level. The present results provide initial insights into the behavioral and neural consequences of instructed attention and emotional distraction during WM encoding.

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