Localization of function in anterior cingulate cortex: from psychosurgery to functional neuroimaging.

Early localizationists linked anterior cingulate cortex (ACC: Brodmann's area 24 and adjacent regions) with emotional behavior, paving the way for bilateral cingulotomy psychosurgery in severe, treatment resistant, cases of obsessive-compulsive disorder, chronic pain, depression, and substance abuse. Neuropsychological follow-up of such cases demonstrated executive function impairment. Abnormal neuroimaged activity in ACC has been found in many psychiatric conditions, including obsessive-compulsive disorder, chronic pain, substance abuse, and schizophrenia. With healthy participants, increased neuroimaged activity in ACC has been linked with challenging executive function tasks, homeostatically incongruous physical states, and the encoding of the pleasant/averseness of stimuli. There is disagreement on the cortical substrate subsumed by the term ACC, the existence of functionally distinct ACC subregions (e.g., dorsal: cognitive vs. ventral: emotion), and the interpretation of functional neuroimaging studies. Synthesis of neuropsychological and functional neuroimaging studies suggests ACC contributes to behavior by modifying responses especially in reaction to challenging cognitive and physical states that require additional effortful cognitive control. This is accomplished by monitoring the emotional salience of stimuli, exerting control over the autonomic nervous system, and modulating cognitive activity.