Subcortical grey matter structures in multiple sclerosis: what is their role in cognition?

The present study aimed to investigate altered grey matter (GM) and functional connectivity (FC) in deep subcortical areas, such as the thalamus and basal ganglia, and their relationship with cognitive impairment (CI) in multiple sclerosis (MS). Thirty-six patients were neuropsychologically assessed, classified as cognitive preserved (CP) and CI, and were compared with 18 healthy controls. GM atrophy and FC were observed in 10 predefined functional areas of the thalamus and in six of basal ganglia. GM atrophy was prominent in the basal ganglia in CI patients compared with CP MS patients. Increased FC was observed between the right caudate and the bilateral orbitofrontal cortex in CI versus CP patients. The discriminant and correlation analyses showed that the enhanced FC observed between the right caudate and the orbitofrontal cortex was closely associated with CI in MS patients. In conclusion, reduced GM volume and enhanced frontobasal ganglia connectivity are related to cognition in MS patients.