scholarly journals The cerebellum and its network: Disrupted static and dynamic functional connectivity patterns and cognitive impairment in multiple sclerosis

2021 ◽  
pp. 135245852199927
Author(s):  
Menno M Schoonheim ◽  
Linda Douw ◽  
Tommy AA Broeders ◽  
Anand JC Eijlers ◽  
Kim A Meijer ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Cognitive Impairment ◽  
Functional Connectivity ◽  
Resting State ◽  
Structural Damage ◽  
Grey Matter ◽  
Grey Matter Volume ◽  
Default Mode ◽  
Cerebellar Damage ◽  
The Impact

Background: The impact of cerebellar damage and (dys)function on cognition remains understudied in multiple sclerosis. Objective: To assess the cognitive relevance of cerebellar structural damage and functional connectivity (FC) in relapsing-remitting multiple sclerosis (RRMS) and secondary progressive multiple sclerosis (SPMS). Methods: This study included 149 patients with early RRMS, 81 late RRMS, 48 SPMS and 82 controls. Cerebellar cortical imaging included fractional anisotropy, grey matter volume and resting-state functional magnetic resonance imaging (MRI). Cerebellar FC was assessed with literature-based resting-state networks, using static connectivity (that is, conventional correlations), and dynamic connectivity (that is, fluctuations in FC strength). Measures were compared between groups and related to disability and cognition. Results: Cognitive impairment (CI) and cerebellar damage were worst in SPMS. Only SPMS showed cerebellar connectivity changes, compared to early RRMS and controls. Lower static FC was seen in fronto-parietal and default-mode networks. Higher dynamic FC was seen in dorsal and ventral attention, default-mode and deep grey matter networks. Cerebellar atrophy and higher dynamic FC together explained 32% of disability and 24% of cognitive variance. Higher dynamic FC was related to working and verbal memory and to information processing speed. Conclusion: Cerebellar damage and cerebellar connectivity changes were most prominent in SPMS and related to worse CI.

scholarly journals AEROBIC TRAINING, THE DEFAULT MODE NETWORK, AND COGNITION IN OLDER ADULTS WITH MILD VASCULAR COGNITIVE IMPAIRMENT

2019 ◽  
Vol 3 (Supplement_1) ◽  
pp. S55-S55
Author(s):  
Rachel A Crockett ◽  
Chun Liang Hsu ◽  
Cindy Barha ◽  
Ging-Yuek Robin Hsiung ◽  
Teresa Liu-Ambrose
Keyword(s):  
Older Adults ◽  
Cognitive Impairment ◽  
Cognitive Function ◽  
Functional Connectivity ◽  
Default Mode Network ◽  
Resting State ◽  
Aerobic Training ◽  
Vascular Cognitive Impairment ◽  
Default Mode ◽  
Global Cognitive Function

Abstract Aerobic training has been shown to be effective at improving cognitive and brain outcomes in older adults with mild subcortical ischemic vascular cognitive impairment (SIVCI). However, uncertainty remains regarding the underlying neurobiological mechanisms by which exercise elicits these improvements in cognition. Increased aberrant functional connectivity of the default mode network has been highlighted as a factor contributing to cognitive decline in older adults with cognitive impairment. Greater connectivity of the DMN at rest is associated with poorer performance on attention-demanding tasks, indicative of a lack of ability to deactivate the network on task. Our previous work on a randomized controlled trial of participants with mild SIVCI, demonstrated that 6-months of thrice weekly aerobic training led to improved global cognitive function, as measured by Alzheimer’s disease Assessment Scale-Cognitive subscale (ADAS-Cog), compared with a health education program. Thus, we conducted secondary analyses to investigate whether these changes in global cognitive function were associated with changes in resting state DMN connectivity. A subsample of 21 participants underwent a resting state functional magnetic resonance imaging (fMRI) scan before and after trial completion. Change in resting state DMN connectivity was found to significantly predict change in ADAS-Cog score (β = -.442, p=.038) after controlling for age, intervention group, and baseline functional capacity (R2=.467, F(4,16)= 3.507, p=.031). These findings suggest that functional connectivity of the DMN may underlie changes in global cognitive function. Furthermore, aerobic exercise is a promising intervention by which to elicit these changes in older adults with mild SIVCI.

Hemispheric asymmetries of functional connectivity and grey matter volume in the default mode network

2012 ◽  
Vol 50 (7) ◽  
pp. 1308-1315 ◽  
Author(s):  
Victor M. Saenger ◽  
Fernando A. Barrios ◽  
María L. Martínez-Gudiño ◽  
Sarael Alcauter
Keyword(s):  
Functional Connectivity ◽  
Default Mode Network ◽  
Grey Matter ◽  
Grey Matter Volume ◽  
Hemispheric Asymmetries ◽  
Default Mode ◽  
Matter Volume

scholarly journals Mechanisms of Network Changes in Cognitive Impairment in Multiple Sclerosis

Neurology ◽  
2021 ◽  
pp. 10.1212/WNL.0000000000012834
Author(s):  
Danka Jandric ◽  
Ilona Lipp ◽  
David Paling ◽  
David Rog ◽  
Gloria Castellazzi ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cognitive Impairment ◽  
Functional Connectivity ◽  
Resting State ◽  
Structural Connectivity ◽  
Cognitively Impaired ◽  
Anatomical Connectivity ◽  
Cross Sectional

Background and Objectives:Cognitive impairment in multiple sclerosis (MS) is associated with functional connectivity abnormalities. While there have been calls to use functional connectivity measures as biomarkers there remains to be a full understanding of why they are affected in MS. In this cross-sectional study we tested the hypothesis that functional network regions may be susceptible to disease-related ‘wear-and-tear’ and that this can be observable on co-occuring abnormalities on other MR metrics. We tested whether functional connectivity abnormalities in cognitively impaired MS patients co-occur with either 1) overlapping, 2) local, or 3) distal changes in anatomical connectivity and cerebral blood flow abnormalities.Methods:Multimodal 3T MRI and assessment with the Brief Repeatable Battery of Neuropsychological tests was performed in 102 relapsing-remitting MS patients and 27 healthy controls. MS patients were classified as cognitively impaired if they scored ≥1.5 standard deviations below the control mean on ≥2 tests (n=55), or else cognitively preserved (n=47). Functional connectivity was assessed with Independent Component Analysis and dual regression of resting-state fMRI images. Cerebral blood flow maps were estimated and anatomical connectivity was assessed with anatomical connectivity mapping and fractional anisotropy of diffusion-weighted MRI. Changes in cerebral blood flow and anatomical connectivity were assessed within resting state networks that showed functional connectivity abnormalities in cognitively impaired MS patients.Results:Functional connectivity was significantly decreased in the anterior and posterior default mode networks and significantly increased in the right and left frontoparietal networks in cognitively impaired relative to cognitively preserved MS patients (TFCE-corrected at p≤0.05, two-sided). Networks showing functional abnormalities showed altered cerebral blood flow and anatomical connectivity locally and distally but not in overlapping locations.Discussion:We provide the first evidence that FC abnormalities are accompanied with local cerebral blood flow and structural connectivity abnormalities but also demonstrate that these effects do not occur in exactly the same location. Our findings suggest a possibly shared pathological mechanism for altered functional connectivity in brain networks in MS.

scholarly journals Increased functional sensorimotor network efficiency relates to disability in multiple sclerosis

2020 ◽  
pp. 135245852096629
Author(s):  
Myrte Strik ◽  
Declan T Chard ◽  
Iris Dekker ◽  
Kim A Meijer ◽  
Anand JC Eijlers ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Logistic Regression ◽  
Functional Connectivity ◽  
Structural Damage ◽  
Premotor Cortex ◽  
Functional Network ◽  
Grey Matter Volume ◽  
Network Efficiency ◽  
Brain Volumes ◽  
Disability Status

Background: Network abnormalities could help explain physical disability in multiple sclerosis (MS), which remains poorly understood. Objective: This study investigates functional network efficiency changes in the sensorimotor system. Methods: We included 222 MS patients, divided into low disability (LD, Expanded Disability Status Scale (EDSS) ⩽3.5, n = 185) and high disability (HD, EDSS ⩾6, n = 37), and 82 healthy controls (HC). Functional connectivity was assessed between 23 sensorimotor regions. Measures of efficiency were computed and compared between groups using general linear models corrected for age and sex. Binary logistic regression models related disability status to local functional network efficiency (LE), brain volumes and demographics. Functional connectivity patterns of regions important for disability were explored. Results: HD patients demonstrated significantly higher LE of the left primary somatosensory cortex (S1) and right pallidum compared to LD and HC, and left premotor cortex compared to HC only. The logistic regression model for disability ( R2 = 0.38) included age, deep grey matter volume and left S1 LE. S1 functional connectivity was increased with prefrontal and secondary sensory areas in HD patients, compared to LD and HC. Conclusion: Clinical disability in MS associates with functional sensorimotor increases in efficiency and connectivity, centred around S1, independent of structural damage.

scholarly journals Predictions of Current and Future Episodic Memory Using Grey Matter Volume and Functional Connectome: A Longitudinal Study in Amnestic Mild Cognitive Impairment Patients

2020 ◽  
Author(s):  
Zan Wang ◽  
Hao Shu ◽  
Duan Liu ◽  
Fan Su ◽  
Chunming Xie ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Episodic Memory ◽  
Grey Matter ◽  
Verbal Learning ◽  
Amnestic Mild Cognitive Impairment ◽  
Grey Matter Volume ◽  
Default Mode ◽  
Matter Volume ◽  
Limbic Systems

Abstract Background: Amnestic mild cognitive impairment (aMCI) patients are considered an at-risk group for progression to Alzheimer’s dementia and accurate prediction of aMCI progression could facilitate the optimal decision-making for both clinicians and patients. Based on the baseline whole-brain grey-matter volume (GMV) and resting-state functional connectivity (FC), we used relevance vector regression to predict the baseline and longitudinal Rey’s Auditory Verbal Learning Test Delayed Recall (AVLT-DR) scores of individual aMCI patients.Methods: Fifty aMCI patients completed baseline and 3-year follow-up visits. All patients underwent comprehensive neuropsychological assessments and multimodal brain MRI scans.Results: We found that the GMV pattern predicted the baseline AVLT-DR score, while the pattern of FC predicted the longitudinal AVLT-DR score. In particular, GMV predicted the baseline AVLT-DR score with an accuracy of r = 0.54 (P < 0.001); the regions that contributed the most were within the default mode (e.g., the posterior cingulate gyrus, angular gyrus and middle temporal gyrus) and limbic systems (e.g., the hippocampus and parahippocampal gyrus). The FC predicted the longitudinal AVLT-DR score with an accuracy of r = 0.50 (P < 0.001), and the connections that contributed the most were the within- and between-system connectivity of the default mode and limbic systems. As a complement, we demonstrated that the GMV and FC patterns could also effectively predict the baseline and longitudinal composite episodic memory scores (calculated by averaging three well-known episodic memory test scores).Conclusions: Our results demonstrated the multimodal brain features in the individualized prediction of aMCI patients’ current and future episodic memory performance. These “neural fingerprints” have the potential to be biomarkers for aMCI patients and can help medical professionals optimize individual patient management and longitudinal evaluation.

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