“Each electrical pulse—and resulting squirt of neurotransmitter—is not an order commanding the next neuron’s actions; it is more like a vote on what the next neuron should do. The whole pattern of activity is like a presidential election. Everyone votes on who the president should be, and depending on those votes, the country veers off in one direction or another. If you can change the number of votes in a few key swing states by only a few percentage points, you can dramatically change the course of the country. The same is true of the brain. By changing the firing rate of neurons in a few key regions, you can influence the pattern of activity in the entire brain.”