Functional Connectivity and Neural Activity from Subacute to Late-Chronic Left Ischemic Stroke
Poster No:
1466
Submission Type:
Abstract Submission
Authors:
Nicholas Parsons1, Govinda Poudel2, Natalia Egorova-Brumley3, William Pham4, Mohamed Salah Khlif5, Amy Brodtmann6
Institutions:
1Cognitive Health Initiative, School of Translational Medicine (STM), Monash University, Melbourne, Victoria, 2Australian Catholic University, Melbourne, Victoria, 3University of Melbourne, Melbourne, Victoria, 4Monash University, Melbourne, Victoria, 5Monash University, Melbourne, VIC, 6Cognitive Health Initiative, School of Translational Medicine (STM), Monash University, Melbourne, VIC
First Author:
Nicholas Parsons, Ph.D
Cognitive Health Initiative, School of Translational Medicine (STM), Monash University
Melbourne, Victoria
Cognitive Health Initiative, School of Translational Medicine (STM), Monash University
Melbourne, Victoria
Co-Author(s):
Amy Brodtmann
Cognitive Health Initiative, School of Translational Medicine (STM), Monash University
Melbourne, VIC
Cognitive Health Initiative, School of Translational Medicine (STM), Monash University
Melbourne, VIC
Introduction:
Stroke is a leading cause of mortality and long-term disability, associated with widespread functional connectivity (FC) changes and local neural disruptions (GBD 2021 Stroke Risk Factor Collaborators, 2024). We examined FC and amplitude of low-frequency fluctuations (ALFF) across motor and visual networks at subacute (3-months), early chronic (1-year), and late chronic (3-years) phases. Motor and visual networks were chosen as these are commonly affected in stroke.
Methods:
Ninety-four ischemic stroke survivors and 35 sex- and age-matched controls were recruited as part of the Cognition and Neocortical Volume After Stroke (CANVAS) study. Resting-state fMRI data (7-min) at 3 months, 1 year, and 3 years were examined. Exclusion criteria included hemorrhagic stroke, dementia, and neurodegenerative disorders. FC was analyzed using ROI-to-ROI and seed-to-voxel mapping, while ALFF was computed from bandpass-filtered (0.01–0.08 Hz) BOLD signals. Longitudinal group-by-time analyses used generalized linear models with FDR correction.
Results:
In left stroke patients, FC significantly decreased between 1 and 3 years post-stroke, particularly between the right supplementary motor area (SMA) and visual regions, including the right lingual gyrus (T(56) = -4.67, p = 0.000019, pFDR = 0.003; See Figure 1). ALFF increased in the anterior cingulate cortex at 3 months (peak cluster: 101 voxels, p < 0.001) and shifted to cerebellar regions at 1 year (peak cluster: 111 voxels, p < 0.001). ALFF at 3 months negatively predicted 1-year FC (r = -0.224, p < 0.001; See Figure 2).
·Figure 1: Longitudinal changes in functional connectivity (FC) in left stroke and control groups over three years.
·Figure 2: Amplitude of Low-Frequency Fluctuation (ALFF) Following Left Stroke.
Conclusions:
Increased ALFF in regions functionally connected to the visual cortex may reflect early efforts to recruit additional resources and establish new pathways for information processing. These compensatory mechanisms likely represent a response to ongoing grey and white matter degeneration, which persists for years after stroke (Brodtmann et al., 2023; Duering et al., 2015). Examination of these processes reveals how regional activity and network reorganization contribute to long-term structural adaptation and recovery, and may inform the development of targeted interventions.
Modeling and Analysis Methods:
Activation (eg. BOLD task-fMRI)
fMRI Connectivity and Network Modeling 1
Novel Imaging Acquisition Methods:
BOLD fMRI 2
Keywords:
FUNCTIONAL MRI
Other - Stroke
1|2Indicates the priority used for review
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Were any human subjects research approved by the relevant Institutional Review Board or ethics panel? NOTE: Any human subjects studies without IRB approval will be automatically rejected.
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Provide references using APA citation style.
Duering, M., Righart, R., Wollenweber, F. A., Zietemann, V., Gesierich, B., & Dichgans, M. (2015). Acute infarcts cause focal thinning in remote cortex via degeneration of connecting fiber tracts. Neurology, 84(16), 1685-1692.
GBD 2021 Stroke Risk Factor Collaborators. (2024). Global, regional, and national burden of stroke and its risk factors, 1990–2021: A systematic analysis for the Global Burden of Disease Study 2021. The Lancet Neurology, 23(10), 973–1003.