The anterior cingulate cortex and the phonatory control in monkey and man

Electrical stimulation of the anterior cingulate cortex yields vocalization in the monkey. The elicited vocalizations seem to represent primary stimulus responses. Monkeys are not able to perform a vocal conditioning task after ablation of the anterior cingulate cortex. However, they can carry out a lever-pressing conditioning task following destruction of this area. It is hypothesized that the anterior cingulate cortex exerts the volitional control of species-specific vocalizations in monkey. The non-verbal emotional vocal utterances are considered to be the human homologue of monkey's vocalizations. Therefore, bilateral lesion of the anterior cingulate cortex in man should hamper the volitional control of emotional vocal utterances in man as it does in monkeys. One personal observation is reported where after a bilateral infarction of the anterior cingulate cortex the patient's voice showed a permanent lack of emotional expression. The anterior cingulate cortex seems to play the decisive role in the volitional verbalization of emotions.