With all the hormones and whatnot inside. Dopamine, adrenaline, melatonin, whatever. Also, there’s this Hunter S. Thompson bit on the… pineal gland?
If it had an effect on you, wouldn’t it be a really messed up high, all over the place? With uppers, downers etc mixed? (Not including the emotional implications of eating raw human brains.)
As part of mourning people would eat parts of dead family members.
Also alot of people who find out about this think you’ll get it from eating just anyone’s brain but the chance of developing the initial desiese is literally one in a milion, not that you should go around eating brains