A 38-yeаr-оld mаn is brоught tо his primаry care physician at the urging of his wife due to a personality change over the past 5 months. The patient denies having any current concerns, but his wife reports that he has become more irritable, impulsive, and has started making sexually inappropriate comments to underage family members. She informs you that the patient’s father had similar symptoms starting at 42 years old. Physical examination is notable for involuntary movements of the tongue. He has a sudden involuntary jerking movement of the upper extremity that he attempts to hide by straightening his glasses. Which of the following regions of the brain is most likely affected?