Intracranial electrophysiology of the human orbitofrontal cortex

AbstractThis chapter describes studies exploring the functions of the orbitofrontal cortex using invasive neurophysiological methods in humans. The neurosurgical implantation of depth electrodes is limited to clinical settings, but provides a unique opportunity to measure directly neural activity. After describing techniques for intracranial recording and analysis, the chapter focuses on activity recorded in relation to positive and negative emotional stimuli involving facial expressions and scenes. Studies relating activity to expectation of reward and punishment in tasks such as the Iowa Gambling Task are also described. These studies reveal a complex range of response properties in orbitofrontal neurons consistent with a role in emotion, decision making, and social processing. Of particular interest are responses that were observed to aversive visual stimuli, and also responses with remarkably short latencies, suggesting that neurons in the orbitofrontal cortex may participate in relatively rapid, automatic processing of threat-related stimuli.