Despite rumors to the contrary, there’s many ways in which the
human brain isn’t all that fancy. Let’s compare it to the
nervous system of a fruit fly. Both are made up of cells — of
course — with neurons playing particularly important roles. Now
one might expect that a neuron from a human will differ
dramatically from one from a fly. Maybe the human’s will have
especially ornate ways of communicating with other neurons,
making use of unique “neurotransmitter” messengers. Maybe
compared to the lowly fly neuron, human neurons are bigger, more
complex, in some way can run faster and jump higher. But no.
Look at neurons from the two species under a microscope and they
look the same. They have the same electrical properties, many of
the same neurotransmitters, the same protein channels that allow
ions to flow in and out, as well as a remarkably high number of
genes in common. Neurons are the same basic building blocks in
both species. So where’s the difference? It’s numbers — humans
have roughly a million neurons