Behave: The Biology of Humans at Our Best and Worst

by Robert M. Sapolsky

Administer a synthetic version of the neurotransmitter, or a drug that is structurally close enough to the real thing to fool the receptors. Psilocybin, for example, is structurally similar to serotonin and activates a subtype of its receptors.

Acetylcholine stimulates your diaphragm to contract. Curare, the poison used in darts by Amazonian tribes, blocks acetylcholine receptors. You stop breathing.

What might we call the consequence of some types of atypically wide associative nets of neurons? Creativity.

Back to that myelin wrapping around axons that helps action potentials propagate faster. Myelin tends to be white, sufficiently so that the fiber tract cables in the brain look white. Thus they’re generically referred to as “white matter.”

Given that every brain region is getting projections from and sending projections to a zillion other places, it is rare that an individual brain region is “the center for” anything. Instead it’s all networks where, far more often, a particular region “plays a key role in,” “helps mediate,” or “influences” a behavior. The function of a particular brain region is embedded in the context of its connections.