Speech hastening during electrical stimulation of left premotor cortex

Cortical and axonal electrical stimulation of left premotor cortex and SMA during awake brain surgery yielded unique behavioral responses. In two patients, there was involuntary acceleration of speech (i.e., speech hastening) during a counting or picture naming task. In one patient, stimulation led to a deceleration of the rate with which three different tasks were performed (arm movements, finger tapping and counting). Possible explanatory mechanisms are discussed, and the literature on so-called "negative motor areas" is shortly reviewed. It is argued that the function of loops between cortex and basal ganglia were modulated via stimulation of frontostriatal and/or fronto-opercular pathways.