ABSTRACT
Cortical electrical stimulation, first performed by Bartholow in 1874, has become a gold standard method to explore various cortical functions and has greatly aided the field of functional neurosurgery to preserve eloquent cortices. Intracortical microstimulation techniques have evaluated orthodromic or antidromic responses in the remote cortical regions via cortico-cortical connections. Intracortical connections in humans have been studied almost exclusively by gross anatomic dissections. Direct cortical electrical stimulation has been shown to activate neurons in the motor cortex using not only conventional repetitive stimulation but also with single pulse stimulation. Direct cortical stimulation with single electric pulses through subdural electrodes elicited motor evoked potentials in awake patients with medically intractable partial epilepsy or multiple system atrophy. The present cortico-cortical evoked potentials studies revealed short and long cortico-cortical connections in vivo. Long cortico-cortical connections were observed by stimulating the lateral ventral or mesial prefrontal area.
