Audiovisual feature association in the auditory cortex
Poster Presentation

Julien Besle
INSERM Unité 280

*Marie-Hélène Giard
INSERM Unité 280

     Abstract ID Number: 135
     Full text: PDF
     Last modified: July 18, 2005

Abstract
The Mismatch Negativity (MMN) is a component of the auditory event-related potentials that is automatically generated in the auditory cortex when incoming sounds are detected as deviating from a neural representation of acoustic regularities (e.g. when infrequent « deviant » tones are presented among frequent « standard » tones). It can thus be used as a probe to study the representation of sounds in the Auditory Sensory Memory. To study the influence of visual information on this representation, standard and deviant sounds were presented to 16 subjects in three conditions, while they were performing a distractive task: the auditory stimulus was associated with either always the same visual stimulus, or no visual stimulus, or several different equiprobable visual stimuli. Event related-potentials were recorded from 36 electrodes at the scalp surface. The results showed that the presence of visual information enhanced the amplitude of the MMN, but only when visual information was consistent across all standard trials (i.e. only when the visual stimulus was always the same). This suggests that relevant auditory and visual features may be associated in the auditory cortex to produce a representation of audiovisual events in the auditory sensory memory.