The case for early feedforward integration of multisensory inputs
Multiple Paper Presentation

John J. Foxe
Nathan Kline Institute for Psychiatric Research and Albert Einstein College of Medicine

Charles Schroeder
Nathan Kline Institute for Psychiatric Research and Albert Einstein College of Medicine

     Abstract ID Number: 147

Abstract
A widely held view in the field of multisensory science is that sensory information from a single object (e.g. a barking dog) is first processed extensively through the respective unisensory processing streams before the information is combined in higher-order multisensory regions of cortex. Under this view, multisensory modulations found in early sensory cortices during hemodynamic imaging studies have been interpreted as reflecting feedback modulations that occur subsequent to multisensory processing in the higher-order areas. Of course, hemodynamic imaging cannot address the relative timing of such activations. The present article reports on recent evidence from both human and monkey electrophysiological investigations that challenge an exclusively feedback model. Specifically, these studies show that multisensory integration effects are seen at very early latencies relative to the well-established timecourse of sensory activation within the respective unisensory processing streams. Further, intracranial recordings show that multisensory inputs found in early sensory cortices display a characteristic feedforward pattern of inputs. Lastly, recent anatomic tracer studies have begun to uncover direct connections between early visual and auditory sensory regions that were previously thought not to exist, providing the necessary anatomic substrate for such early interactions. In light of these recent findings, it is becoming evident that models of multisensory cortical processing will need to incorporate early feedforward integration mechanisms as well as feedback.

To be Presented at the Following Symposium:
Contributions of Feedforward, Feedback and Lateral projections to Multisensory Convergence and Integration.
Other papers in this Symposium:

• Charles E. Schroeder
  Cognitive Neuroscience & Schizophrenia Program, Nathan Kline Institute and Department of Neuroscience, Albert Einstein College of Medicine
  John F. Smiley
  Program in Cognitive Neuroscience and Schizophrenia,Nathan Kline Institute
  Peter Lakatos
  Program in Cognitive Neuroscience and Schizophrenia,Nathan Kline Institute
  Tammy McGinnis
  Program in Cognitive Neuroscience and Schizophrenia,Nathan Kline Institute
  M. Noelle O'Connell
  Program in Cognitive Neuroscience and Schizophrenia,Nathan Kline Institute
  Troy A. Hackett
  Hearing/Speech Sciences,Vanderbilt University
  Neural mechanisms and functional significance of multisensory convergence in early auditory cortical processing
• Helen Ruth Clemo
  Department of Physiology, Virginia Commonwealth University
  Alex Meredith
  Anatomy and Neurobiology, Virginia Commonwealth University
  Feedback projections and multisensory convergence in higher-level association areas of cat cortex
• Henry Kennedy
  Unit 371 INSERM
  Arnaud Falchier
  INSERM
  Ken Knoblauch
  INSERM
  Bertrand Jouve
  Dept de Mathématiques et Informatique, University Toulouse 2 le Mirrail
  Eccentricity has a major influence on cortico-cortical connectivity of areas V1, V2 and V4 in the macaque