The cingulate hidden hand

Studies on primates, and increasing evidences in humans, support the notion that the anterior cingulate cortex, which subserves various executive functions, is involved in the preparation and execution of motor operations.1 Recently, the specific role of the caudal part of the anterior cingulate cortex in manual control has been demonstrated in a patient with a focal anterior cingulate cortex lesion,2 thus providing additional arguments for the functional specialisation of cingulate motor areas in the human brain. Interestingly, the damaged area widely overlapped a more anterior part of Brodmann's area 24 from where complex coordinated movements adapted to environmental constraints have been electrically induced in epileptic patients (figure A).3Both areas encompass dorsally the ventral bank of the cingulate sulcus, at a level that seems to correspond to the simian rostral cingulate motor area (CMAr),1 but whether this region is specifically involved in voluntary movements in humans is not known. We report a finding which shows for the first time that compulsive goal directed motor behaviour can be electrically induced in humans by stimulating the anterior cingulate sulcus. Anatomical representation of the electrical stimulation site. (A) Normalised proportional grid system …