Neurobiological mechanisms underlying emotional processing in relapsing-remitting multiple sclerosis

Area of Science:

• Neuroscience
• Psychiatry
• Medical Imaging

Background:

• Affective disorders are common and disabling in multiple sclerosis (MS), but their neurobiological underpinnings are not fully understood.
• Previous studies implicated frontal and temporal cortex damage, but functional brain dynamics in emotional processing remain under-investigated.
• Functional magnetic resonance imaging (fMRI) is suitable for exploring emotional processing and functional connectivity in MS.

Purpose of the Study:

• To investigate the neural substrates and functional connectivity underlying emotional processing in multiple sclerosis patients.
• To compare brain responses and functional connectivity during emotional tasks between MS patients and healthy controls.

Main Methods:

• fMRI was used to record brain responses in 12 relapsing-remitting MS patients (cognitively unimpaired, no disease-modifying therapies) and 12 healthy controls during an emotional stimuli processing task.
• Structural imaging measures (lesion load, grey/white matter/brain volumes) were recorded to control for disease-related effects.
• Functional connectivity analysis focused on prefrontal cortex (PFC) and amygdala interactions.

Main Results:

• Despite similar task performance and structural measures, MS patients exhibited significantly greater activation in the ventrolateral PFC compared to controls.
• MS patients showed reduced functional connectivity between prefrontal areas and the amygdala.
• These alterations in brain activity and connectivity were observed despite no significant differences in structural measures.

Conclusions:

• Pathological changes in MS likely disrupt communication between key emotional processing regions, such as the PFC and amygdala.
• Enhanced ventrolateral PFC responses may represent adaptive or compensatory mechanisms to mitigate emotional symptoms in MS.
• The findings provide novel insights into the neurobiology of emotional dysfunction in MS, potentially resembling mechanisms in psychiatric disorders.