Brain network segregation and integration during an epoch-related working memory fMRI experiment

10.1101/252338 ◽

2018 ◽

Author(s):

Peter Fransson ◽

Björn C. Schiffler ◽

William Hedley Thompson

Keyword(s):

Working Memory ◽

Brain Network ◽

High Temporal Resolution ◽

Imaging Data ◽

Drift Diffusion Model ◽

Drift Diffusion ◽

Point Estimates ◽

Fmri Experiment ◽

Temporal Profiles

AbstractThe characterization of brain subnetwork segregation and integration has previously focused on changes that are detectable at the level of entire sessions or epochs of imaging data. In this study, we applied time-varying functional connectivity analysis together with temporal network theory to calculate point-by-point estimates in subnetwork segregation and integration during an epoch-based (2-back, 0-back, baseline) working memory fMRI experiment as well as during resting-state. This approach allowed us to follow task-related changes in subnetwork segregation and integration at a high temporal resolution. At a global level, the cognitively more taxing 2-back epochs elicited an overall stronger response of integration between subnetworks compared to the 0-back epochs. Moreover, the visual and fronto-parietal subnetworks displayed characteristic and distinct temporal profiles of segregation and integration during the 0- and 2-back epochs. During the interspersed epochs of baseline, many subnetworks, including the default mode, visual, fronto-parietal, cingulo-opercular and dorsal attention subnetworks showed pronounced increases in segregation. Using a drift diffusion model we show that the response time for the 2-back trials are correlated with integration for the fronto-parietal subnetwork and correlated with segregation for the visual subnetwork. Our results elucidate the fast-evolving events with regard to subnetwork integration and segregation that occur in an epoch-related task fMRI experiment. Our findings suggest that minute changes in subnetwork integration are of importance for task performance.

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Traumatic brain injury alters the functional brain network mediating working memory

Brain Injury ◽

10.3109/02699052.2011.608210 ◽

2011 ◽

Vol 25 (12) ◽

pp. 1170-1187 ◽

Cited By ~ 43

Author(s):

Maki Kasahara ◽

David K. Menon ◽

Claire H. Salmond ◽

Joanne G. Outtrim ◽

Joana V. Taylor Tavares ◽

...

Keyword(s):

Traumatic Brain Injury ◽

Working Memory ◽

Brain Injury ◽

Brain Network ◽

Functional Brain ◽

Functional Brain Network

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Cognitive Aftereffects of Acute tDCS Coupled with Cognitive Training: An fMRI Study in Healthy Seniors

Neural Plasticity ◽

10.1155/2021/6664479 ◽

2021 ◽

Vol 2021 ◽

pp. 1-10

Author(s):

P. Šimko ◽

M. Pupíková ◽

M. Gajdoš ◽

I. Rektorová

Keyword(s):

Older Adults ◽

Working Memory ◽

Cognitive Training ◽

Brain Network ◽

Resting State Functional Connectivity ◽

Double Blind ◽

Sham Stimulation ◽

Highly Educated ◽

Fmri Study ◽

Dorsolateral Prefrontal

Enhancing cognitive functions through noninvasive brain stimulation is of enormous public interest, particularly for the aging population in whom processes such as working memory are known to decline. In a randomized double-blind crossover study, we investigated the acute behavioral and neural aftereffects of bifrontal and frontoparietal transcranial direct current stimulation (tDCS) combined with visual working memory (VWM) training on 25 highly educated older adults. Resting-state functional connectivity (rs-FC) analysis was performed prior to and after each stimulation session with a focus on the frontoparietal control network (FPCN). The bifrontal montage with anode over the left dorsolateral prefrontal cortex enhanced VWM accuracy as compared to the sham stimulation. With the rs-FC within the FPCN, we observed significant stimulation × time interaction using bifrontal tDCS. We found no cognitive aftereffects of the frontoparietal tDCS compared to sham stimulation. Our study shows that a single bifrontal tDCS combined with cognitive training may enhance VWM performance and rs-FC within the relevant brain network even in highly educated older adults.

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Declined functional connectivity of white matter during rest and working memory tasks associates with cognitive impairments in schizophrenia

10.1101/2020.05.16.20091397 ◽

2020 ◽

Cited By ~ 1

Author(s):

Yurui Gao ◽

Muwei Li ◽

Anna S Huang ◽

Adam W Anderson ◽

Zhaohua Ding ◽

...

Keyword(s):

Working Memory ◽

White Matter ◽

Functional Connectivity ◽

Resting State ◽

Spatial Working Memory ◽

Cognitive Impairments ◽

Memory Task ◽

Brain Network ◽

Blood Oxygenation ◽

Cerebral Peduncle

BACKGROUND: Schizophrenia, characterized by cognitive impairments, arises from a disturbance of brain network. Pathological changes in white matter (WM) have been indicated as playing a role in disturbing neural connectivity in schizophrenia. However, deficits of functional connectivity (FC) in individual WM bundles in schizophrenia have never been explored; neither have cognitive correlates with those deficits. METHODS: Resting-state and spatial working memory task fMRI images were acquired on 67 healthy subjects and 84 patients with schizophrenia. The correlations in blood-oxygenation-level-dependent (BOLD) signals between 46 WM and 82 gray matter regions were quantified, analyzed and compared between groups under three scenarios (i.e., resting state, retention period and entire time of a spatial working memory task). Associations of FC in WM with cognitive assessment scores were evaluated for three scenarios. RESULTS: FC deficits were significant (p<.05) in external capsule, cingulum, uncinate fasciculus, genu and body of corpus callosum under all three scenarios. Deficits were also present in the anterior limb of the internal capsule and cerebral peduncle in task scenario. Decreased FCs in specific WM bundles associated significantly (p<.05) with cognitive impairments in working memory, processing speed and/or cognitive control. CONCLUSIONS: Decreases in FC are evident in several WM bundles in patients with schizophrenia and are significantly associated with cognitive impairments during both rest and working memory tasks. Furthermore, working memory tasks expose FC deficits in more WM bundles and more cognitive associates in schizophrenia than resting state does.

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