Does object-related visual cortex ‘listen’ to natural sounds?
Poster Presentation

Marcus Johannes Naumer
Department of Neurophysiology, Max Planck Institute for Brain Research, Institute of Medical Psychology, Frankfurt Medical School, and Brain Imaging C

Michael Wibral

Wolf Singer

Lars Muckli

     Abstract ID Number: 60
     Full text: Not available
     Last modified: March 17, 2005

Abstract
We investigated the neural basis of object-related audio-visual integration. We hypothesized an involvement of ventral occipito-temporal regions (visual ‘what’ pathway) even during unimodal auditory stimulation. As these regions are largely invariant to the exact physical stimulus features, but are sensitive to context information and object category, we employed a category-related design. Natural sounds and gray-scaled pictures of sportsmen, animals, and cars were presented in separate stimulation blocks during BOLD-fMRI measurements at 3 Tesla. Inter-individual variation in cortical gyrification was corrected using cortex-based inter-subject alignment (BrainVoyager QX). We employed conjunction analyses of single-subject and group-averaged (n=10) data and searched for cortical regions that showed an object category preference during both unimodal visual and unimodal auditory stimulation. We found distinct peak activations in ventral occipito-temporal cortex for sportsmen, animals, and cars, respectively. BOLD signal increases in these regions were found to be significantly larger during presentation of visual as compared to auditory objects. Interestingly, these visual regions did not only show the respective category preference during unimodal visual stimulation, but also during unimodal auditory stimulation. Thus, these regions are involved in object category-related audio-visual integration that might reflect learned associations between radically different object features that co-occur very often in everyday life.