The prefrontal cortex is the most recently evolved part of the cortex, and humans have more of it than any other animal. Our big prefrontal cortex gives us a huge evolutionary advantage, but it can also cause problems. In depression, it is responsible for worrying, guilt, shame, problems with thinking clearly, and indecisiveness. Changing activity in the prefrontal cortex can help with these problems, and it can change bad habits and improve willpower.
