Altered Dynamic Functional Connectivity in Subcortical Ischemic Vascular Disease With Cognitive Impairment.

Area of Science:

• Neuroscience
• Radiology
• Cognitive Science

Background:

• Subcortical ischemic vascular disease (SIVD) is linked to cognitive impairment and altered resting-state functional connectivity (fMRI).
• Dynamic functional connectivity (DFC) analysis reveals temporal fluctuations in brain networks, but its role in SIVD with mild cognitive impairment (MCI) is underexplored.

Purpose of the Study:

• To investigate the impact of cognitive impairment on dynamic functional connectivity (DFC) in SIVD patients.
• To differentiate DFC patterns between SIVD patients with amnestic MCI (SIVD-aMCI) and nonamnestic MCI (SIVD-naMCI) compared to SIVD controls.

Main Methods:

• Applied DFC analysis to resting-state fMRI data from SIVD-Control, SIVD-aMCI, and SIVD-naMCI groups.
• Analyzed mean dwell time of connectivity states and system segregation of functional connectivity (FC) states.
• Correlated DFC measures with behavioral performance on memory and executive function tasks.

Main Results:

• SIVD-related cognitive impairment reduced the mean dwell time of State 3 (strong positive connections), with greater reduction in SIVD-aMCI.
• The correlation between State 3 dwell time and memory/executive function performance became non-significant in MCI groups.
• SIVD-aMCI exhibited significantly lower system segregation of FC states compared to controls and SIVD-naMCI.
• System segregation of State 5 (weak connections) positively correlated with memory performance.

Conclusions:

• Mean dwell time of State 3 and system segregation of State 5 are potential neural markers for cognitive impairments in SIVD.
• DFC alterations reflect the severity and type of cognitive deficits in SIVD patients.
• These findings advance understanding of the neural underpinnings of cognitive impairment in vascular cognitive disorders.