Thalamic-hippocampal-prefrontal disruption in relapsing-remitting multiple sclerosis.

Area of Science:

• Neuroscience
• Neurology
• Medical Imaging

Background:

• Relapsing-remitting multiple sclerosis (RRMS) is associated with gray matter atrophy in the cortex, thalamus, and hippocampus, leading to cognitive deficits.
• The role of white matter pathways like the fornix, cingulum, and uncinate fasciculus (UF) in RRMS cognitive impairment is less understood.

Purpose of the Study:

• To investigate damage to the hippocampal-thalamic-prefrontal network in RRMS.
• To determine the specific contributions of network components to cognitive domains.

Main Methods:

• Diffusion tensor imaging (DTI) was used to measure fractional anisotropy (FA) in the fornix, cingulum, and UF.
• Thalamic and hippocampal volumes were calculated using MRI.
• Neuropsychological tests assessed cognitive domains: attention/executive function, processing speed, verbal memory, and spatial memory.

Main Results:

• RRMS patients exhibited reduced FA in all three white matter pathways and smaller thalamic and hippocampal volumes compared to controls.
• Thalamic volume and Beck Depression Inventory (BDI) scores predicted attention/executive function.
• UF FA predicted processing speed.
• Thalamic volume predicted verbal memory.
• UF FA and BDI scores predicted spatial memory.

Conclusions:

• Disruption of the hippocampal-thalamic-prefrontal network impacts cognitive performance in early RRMS, even with mild impairment.
• Findings confirm both white and gray matter pathology in MS.
• Assessing functional networks is valuable for monitoring cognition in MS.