" I was playing a lot of sports, and that actually changes dopamine signaling in the brain, which helps make life more enjoyable. And going to class not only altered the habit circuit in my brain, but it also meant that I had to spend some time out in the sun on my way to and from classes, which boosted my serotonin and regulated electrical activity in my brain during sleep. "

― Alex Korb , The Upward Spiral: Using Neuroscience to Reverse the Course of Depression, One Small Change at a Time (16pt Large Print Edition)