Non-neocortical GM damage: the hippocampus. A) Extensive hippocampal demyelination observed in post-mortem material. Reproduced from Geurts et al.  with permission from the American Association of Neuropathologists Inc. B) In vivo detection of hippocampal lesions using DIR imaging. Reproduced from Roosendaal et al.  with permission from John Wiley and Sons. C) Hippocampal atrophy on high field MRI provides detailed information on the specific location in the hippocampus where atrophy is present. Reproduced from Sicotte et al.  with permission from Oxford University Press. D) Anno 2011 it is besides structural changes also possible to study functional changes in the hippocampus; the blue areas indicates reduced hippocampal activity in cognitively impaired MS patients compared to healthy controls. Reproduced from Hulst et al.  with permission from John Wiley and Sons.