Brains are overrated
Human intelligence isn't confined to the brain. The nervous system extends all through the body, the brain constantly solicits - and gets - feedback from the legs, back, guts, loins and every other part. "Thinking with your gut" is a real thing, there are more nerve endings there than in the brain of an adult cat.
This is why sentient brains in jars is still science fiction, and likely to remain so. Also why uploading "yourself" is such a stupid idea. The brain and body can't be separated, at least not without effectively destroying whatever owned them.
Biting the hand that feeds IT
