Altered functional connectivity in patients with post-stroke memory impairment: A resting fMRI study

Area of Science:

• Neuroscience
• Cognitive Neurology
• Medical Imaging

Background:

• Post-stroke memory dysfunction (PMD) is a prevalent cognitive impairment following stroke.
• Neural mechanisms underlying PMD are not fully understood, necessitating further investigation.
• The default mode network (DMN) and dorsal attention network (DAN) are critical for cognitive functions, including memory.

Purpose of the Study:

• To investigate dynamic changes in the functional organization of the DMN and DAN in patients with PMD.
• To identify specific brain regions and network alterations associated with memory decline after stroke.
• To elucidate the neural underpinnings of cognitive impairment in stroke survivors.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was employed to assess brain activity.
• Independent component analysis (ICA) was utilized to analyze functional connectivity within and between networks.
• 27 patients with right-hemisphere PMD and 27 matched healthy controls participated.

Main Results:

• Increased functional connectivity was observed between the DMN and prefrontal cortex, temporal regions, and posterior cingulate gyrus/precuneus.
• Decreased functional connectivity was found between the DMN and specific temporal, uvula, and parietal regions.
• The DAN showed decreased functional connectivity with the prefrontal cortex, parietal regions, and insula.

Conclusions:

• Stroke impacts functional connectivity in both lesioned and contralesional hemispheres.
• The prefrontal cortex, temporal regions, insula, and posterior cingulate gyrus/precuneus are crucial for memory processing.
• Altered DMN and DAN connectivity are implicated in post-stroke memory dysfunction.