Hippocampal dysfunction is associated with memory impairment in multiple sclerosis: A volumetric and functional...

Area of Science:

• Neuroscience
• Neuroimaging
• Multiple Sclerosis Research

Background:

• Previous research links hippocampal changes to memory deficits in multiple sclerosis (MS).
• Understanding these alterations is crucial for managing MS-related cognitive decline.

Purpose of the Study:

• To investigate hippocampus volume and functional connectivity (FC) in MS patients with varying episodic memory abilities.
• To identify neuroanatomical and neurofunctional markers differentiating memory profiles in MS.

Main Methods:

• Compared hippocampal subfield volumes and FC in MS patients with impaired (MSi) and preserved (MSp) episodic memory, and healthy controls (HC).
• Utilized discriminant function (DF) analysis to pinpoint key neural parameters associated with memory performance.

Main Results:

• MSi patients exhibited reduced hippocampal subfield volumes compared to MSp and HC groups.
• Functional connectivity (FC) between the posterior hippocampus and cortical areas showed an ordinal gradation (MSi > MSp > HC).
• Reduced right fimbria volume and increased right posterior hippocampus FC were identified as key neural signatures of memory impairment in MSi.

Conclusions:

• Functional connectivity (FC) increases in pathways connecting the hippocampus to cortical areas even before observable memory decline (MSp).
• These FC alterations intensify alongside hippocampal volume reduction and manifest memory deficits (MSi).
• Neuroimaging markers, including hippocampal volume and FC, can identify early and advanced stages of cognitive impairment in MS.