The role of visual cortex in multiple speaker interference
Poster Presentation

Daniel Senkowski
Nathan Kline Institute for Psychiatric Research, The Cognitive Neurophysiology Lab

Dave Saint-Amour
Nathan Kline Institute for Psychiatric Research, The Cognitive Neurophysiology Lab

Thomas Gruber
Universität Leipzig, Institut für Allgemeine Psychologie

John J. Foxe
Nathan Kline Institute for Psychiatric Research, The Cognitive Neurophysiology Lab; City College of the City University of New York, Department of Psychology, Program in Cognitive Neuroscience

     Abstract ID Number: 151
     Full text: Not available
     Last modified: March 21, 2005
     Presentation date: 06/06/2005 11:30 AM in MART Auditorium
     (View Schedule)

Abstract
Humans have the extraordinary ability to follow a conversation while disregarding similar competing visual and auditory signals. To date, the neuronal mechanisms responsible for this ability are not well understood. Here we used a new approach to investigate visual processing in a realistic speech interference situation. Sustained brain activity in cortical networks was monitored by steady-state visual evoked potentials (SSVEPs) while subjects were presented with aligned speakers that produced syllables. Subjects were instructed to detect a target (/ba/) from an attended central speaker while ignoring two surrounding distractor speakers. SSVEPs of target and distractor speakers were simultaneously monitored in an interference condition (syllables from all three speakers) and a non-interference condition (syllable from center speaker only). For the center speaker, we observed a larger decrease in SSVEPs in the interference condition as compared to the non-interference condition over lateral-occipital scalp regions, indicating an amplification of the attended center speaker. Strikingly, an increase in SSVEPs was observed over occipito-temporal scalp regions for the distractors speakers with the highest amplitudes in the interference condition, suggesting an enhanced suppression of the distracter speakers. Our study demonstrated the essential role of amplification and suppression in visual cortex during multiple speaker interference.