How can I resuscitate my brain's "sharpness" after a period of depression?
Use chewing gum.
As it turns out, chewing gum may actually increase blood flow to your brain by 25% - 40%. The chewing movement stimulates the nerves and areas in the brain associated most with arousal, so it may help you feel more awake during the day.
Continuous gum chewing also activates your hippocampus, part of your brain that influences your memory and learning skills. Another surprising benefit of chewing gum is that it may alter your brainwave patterns so that you feel more focused and relaxed.