Hippocampal subfield-specific alterations in post-stroke dementia with subcortical lesion

Area of Science:

• Neuroimaging
• Neurology
• Cognitive Science

Background:

• Hippocampal subfields are crucial for cognition, showing stronger links to performance than the whole hippocampus in dementia.
• The effects of post-stroke dementia (PSD) on hippocampal subfield connectivity are not well understood.

Purpose of the Study:

• To investigate alterations in functional and structural connectivity between hippocampal subfields and cortical regions in PSD patients.
• To compare connectivity changes in PSD patients with post-stroke non-demented (PSND) individuals and normal controls (NC).

Main Methods:

• Utilized resting-state fMRI and DTI to assess functional (fALFF) and structural (FA, diffusivity) properties of hippocampal subfields.
• Constructed functional and structural connectivity matrices between hippocampal subfields and cortical regions.
• Employed linear mixed models for statistical comparisons and correlation analyses.

Main Results:

• PSD patients exhibited distinct functional connectivity changes in hippocampal subfields, particularly with the temporal-occipital cortex, compared to the whole hippocampus.
• Individual hippocampal subfields showed differential contributions to overall hippocampal connectivity alterations.
• Positive correlations between hippocampal tail diffusivity and illness duration were found in PSND patients but not in PSD patients.

Conclusions:

• PSD significantly impacts hippocampal subfield connectivity, providing a more nuanced understanding than whole hippocampus analysis.
• Subfield-specific analysis is essential for elucidating the complex mechanisms underlying PSD.
• Findings suggest distinct neurobiological pathways in PSD compared to non-demented stroke survivors.