Why Zebras Don't Get Ulcers: The Acclaimed Guide to Stress, Stress-Related Diseases, and Coping

by Robert M. Sapolsky

The sympathetic nervous system pulls this off by indirectly arousing the hippocampus into a more alert, activated state, facilitating memory consolidation. This involves an area of the brain that is going to become central to understanding anxiety when we get to chapter 15, namely the amygdala. The sympathetic nervous system has a second route for enhancing cognition. Tons of energy are needed for all that explosive, nonlinear, long-term potentiating, that turning on of light-bulbs in your hippocampus with glutamate. The sympathetic nervous system helps those energy needs to be met by mobilizing glucose into the bloodstream and increasing the force with which blood is being pumped up into the brain. These changes are quite adaptive. When a stressor is occuring it is a good time to be at your best in memory retrieval (“How did I get out of this mess last time?”) and memory formation (“If I survive this, I’d better remember just what I did wrong so I don’t get into a mess like this again.”). So stress acutely causes increased delivery of glucose to the brain, making more energy available to neurons, and therefore better memory formation and retrieval.