EARLY RESPONSES IN THE LATERAL FRONTAL LOBE OF THE HUMAN BRAIN ARE SENSORY
Poster Presentation

Holle Kirchner
Centre de Recherche Cerveau et Cognition, CNRS Toulouse, France

Emmanuel Barbeau
Centre de Recherche Cerveau et Cognition, CNRS Toulouse, France

Simon J. Thorpe
Centre de Recherche Cerveau et Cognition, CNRS Toulouse, France

Jean Régis
Laboratoire de Neurophysiologie et de Neuropsychologie, Hopital de la Timone, Marseille, France

Catherine Liégeois-Chauvel
Laboratoire de Neurophysiologie et de Neuropsychologie, Hopital de la Timone, Marseille, France

     Abstract ID Number: 108
     Full text: Not available
     Last modified: March 17, 2006
     Presentation date: 06/19/2006 4:00 PM in Hamilton Building, Foyer
     (View Schedule)

Abstract
Recent studies have demonstrated a remarkably fast route between brain areas involved in complex scene processing and the oculomotor system (Kirchner & Thorpe, 2006). When, in a choice saccade task, two images are flashed to the left and right of fixation normal subjects can initiate saccades to the side containing an animal in as little as 120-130 ms. One possible route for such ultra-rapid processing could involve the frontal eye fields (FEFs), which in the monkey are known to contain neurons that respond rapidly to the presentation of visual and auditory stimuli. Here, we determined the onset of sensory processing in vicinity to the human FEF using intracranial recordings in a patient with drug-resistant partial epilepsy. When the patient listened passively to different auditory frequencies, the first peak of the auditory evoked potential occurred at an extremely short latency of 34 ms (-16.8 microV). Passive viewing of a checkerboard resulted in a first peak at 53 ms. Given that even these earliest responses in the human FEF were modulated by the stimulus attribute (auditory frequency or visual scene) we conclude that they are sensory in nature and that they might contribute to ultra-rapid processing in the choice saccade task.