The pathophysiology of cognitive dysfunction in multiple sclerosis (MS) has not been elucidated. Possible mechanisms include disconnection of cognitive processing regions by white matter disruption, and direct involvement of cognitively-important grey matter structures. The research presented aims to investigate the neurobiology of cognitive dysfunction in MS using advanced quantitative magnetic resonance imaging (MRI) techniques, and to identify an imaging-based model for predicting cognitive impairment in MS.