Contralateral smile and laughter, but no mirth, induced by electrical stimulation of the cingulate cortex.

The cerebral representation of laughter is dissociated. The emotional aspects seem to be processed in the temporal lobe; whereas the motor features apparently rely on the frontal cortex. In a few prior studies of patients in whom laughter was elicited by electrical stimulation (ES), it always was associated with mirth. We report a patient in whom ES in the right cingulate gyrus elicited smile and laughter, but no mirth. At low voltages, smiling was seen first contralaterally and became bilateral with increasing currents. Our observation supports the concept of the motor representation of laughter in the mesial frontal cortex.