The locus ceruleus projects noradrenaline up into higher regions of the brain where it makes our senses more acute and raises the signal-to-noise ratio of incoming information so we can focus on a current threat or opportunity. It also projects down into the body where it triggers the fight-or-flight response. Dopamine-producing cells in the brain stem project up to the basal ganglia; one of their target areas here is the nucleus accumbens, often called the thrill center of the brain. Dopamine encourages us to engage in physical activities—like hunting, foraging and trading—that lead to
...more
