Chapter 7. The Healthy Brain: "The Hardware of the Soul"

I can drink a double espresso and go to sleep one hour later. My wife cannot drink coffee after 12 noon or she will not be able to sleep that night. Person A can smoke marijuana and sustain productive and creative energy for hours. Person B can smoke the same pot and have an anxiety attack or get depressed. Person C can have a glass or two of wine and leave it at that. Person D cannot stop drinking once he starts. Person E can take prescription medicine to ease nervousness and stop obsessing and gradually regain calmness and control. Person F can take the same medicine for the same reason and become agitated and more anxious. You get the picture. This is called "chemistry," and it varies from person to person.

Have you ever thought of your body as one big chemical reaction? The fact is, the human body undergoes hundreds of billions of chemical reactions every second. "The brain is fundamentally a chemical system," Susan Greenfield writes in The Human Brain: A Guided Tour. "Even the electricity it generates comes from chemicals. Beyond the fluxes of ions into and out of the neurons, a wealth of chemical reactions are occurring incessantly in a bustling but closed world inside the cell."

Indeed, the brain is a dynamic organ with properties and reactions to physical substances and neural stimuli. It's all in your head, remember? Inside your cranium are neurons, protoplasm, nerve cells, axons, dendrites, blood vessels, cerebrospinal ...

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