Inclusion Criteria for patients:  Patients may be diagnosed with:  active RRMS (n=100): Relapsing-remitting course and > 1 clinical relapse and/or signs of MRI activity (> 1 Gd enhancing lesion) during the last year before study enrollment. non-active PMS (n=100): Progressive course (PPMS or SPMS) and no clinical relapses and/or signs of MRI activity during the last year before study enrollment. Age 18-80 years old No other neurological or psychiatric disorder  Inclusion criteria for healthy controls:  Age 18-80 years old No other neurological or psychiatric disorder  Exclusion Criteria for patients and healthy controls:  Pregnancy Contraindication to MRI (eg, claustrophobia, metallic implants, pacemaker etc). Inability to give consent