There's a human prion disease, kuru, which was caused by the practice of funerary cannibalism - where family would ritually consume parts of their deceased relatives' bodies.
The moral of the story seems to be, don't eat brains.
I no longer eat meat, but when I was younger I considered the brains as the tastiest part of an animal, when properly prepared and cooked.
It is said that in USA eating organs is not very popular, so it is likely that many have never experienced well cooked brains, to know what they are missing.
There exists a hypothesis that is rather plausible, that breaking bones and eating their content of brains and marrow has played an important role in the evolution of humans, by providing an abundant source of long-chain fatty acids, enabling the unusual mass ratio between the central nervous system and the whole body that characterizes humans.
Brains, cooked contains 210 calories per 140 g serving. This serving contains 15 g of fat, 16 g of protein and 2.1 g of carbohydrate. The latter is 0 g sugar and 0 g of dietary fiber, the rest is complex carbohydrate. Brains, cooked contains 3.3 g of saturated fat and 4304 mg of cholesterol per serving.
If you do not have risk factors for heart disease, you should limit your cholesterol intake to no more than 300 milligrams a day.
1000% your rda of cholesterol in a single serving!
The moral of the story seems to be, don't eat brains.