Phase resetting of audio-visual multisensory neurons in the human
temporal cortex
Abstract
Integrating auditory and visual inputs plays an important role in
language processing and social perception. We presently investigated
mechanisms of this audio-visual (A-V) integration by analyzing temporal
characteristics of multisensory neurons in the human brain.
Specifically, an inter-trial coherence (ITC, neural index for phase
resetting) of scalp electroencephalography (EEG) were measured while
participants made a temporal-order judgment between a beep (A) and a
flash (V). The posterior temporal region showed higher ITC (phase
resetting) to bimodal (A+V) than unimodal (A or V) stimuli, showing an
involvement of multisensory neurons selectively reacting to the bimodal
inputs. They responded more vigorously as a beep-flash SOA
(stimulus-onset asynchrony) came closer to 0 ms. Finally, this increase
in ITC was most clearly seen in beta band (13-30 Hz). These results
indicate that multisensory neurons with a basic rhythm of 13- 30 Hz play
a critical role in human A-V integration.