Audiovisual interactions during the perception of speech recorded directly from the temporal cortex of epileptic patients
Poster Presentation

Julien Besle
INSERM Unité 280

*Catherine Fischer
Hôpital Neurologique de Lyon

*Olivier Bertrand
INSERM Unité 280

*Marie-Hélène Giard
INSERM Unité 280

     Abstract ID Number: 137
     Full text: Not available
     Last modified: March 21, 2005
     Presentation date: 06/07/2005 9:00 AM in MART Auditorium
     (View Schedule)

Abstract
Even-related potentials were recorded directly from multichannel depth electrodes implanted in the temporal cortex (including the primary and associative auditory cortices and the Superior Temporal Sulcus, STS) of five epileptic patients while they were performing an auditory recognition task among four different natural syllables presented randomly in the auditory, visual or congruent audiovisual conditions. Visual-only syllables elicited long-lasting potentials that were distributed all over temporal sites, including the auditory cortex. In contrast, auditory alone and audiovisual syllables elicited several phasic components in the auditory cortex that began before the arrival of visual information. Comparing the activity elicited by the auditory and the audiovisual syllables, we found that, in three of the patients, some of the auditory components were modulated by the presence of visual information. These were primarily recorded from 75 to 150 ms of auditory processing between the planum temporale and the latero-posterior part of Heschl’s Gyrus. These results bring new insights on the way visual information can directly modulate the early processing of speech information in the auditory cortex.