I spent the first half of the morning, by long-standing arrangement, studying the cross-sections of the brains of people who have suffered from MS. I have never actually seen a brain before, so to speak, in the flesh: all wobbly, made out of tissue like jellified nougat, including the minuscule hippocampus where information is processed and the fatal lesions, small, desiccated, oval areas which are the causes of MS, owing most likely to viral infection. But the causes are not fully understood, nor the reasons why it affects people so differently.
Alongside the yellow-ish bits of cross-section of brain laid out on the slab was what looked like a bit of old rope, but turned out to be a spinal chord, with multiple wires protruding out of the bottom of it which control the movement of the body.
I would post photographs, but there are understandably very strict rules round the photography of grey matter.