Further research on control and inhibition mechanisms will allow for further modifications to the insanity defense. Impaired functioning of the PFC is evidence that a prime factor in mental illness is disrupted volition. Many experiments using fMRI show that one of the functions of the PFC is to bias a person towards taking the more difficult action. This action is representative of a long-term reward, and it is competing with an action that will lead to immediate satisfaction. It is responsible for moral reasoning, including regret. Individual variations that impair the PFC are extremely detrimental to the decision-making process, and give an individual a greater likelihood in a committing a crime he or she would have otherwise not committed.