Cross-modal recruitment of auditory and visual cortices following brief exposure to bimodal stimuli
Poster Presentation

Shahin Zangenehpour
Neuropsychology/Cognitive Neuroscience Unit, Montreal Neurological Institute, Montreal, Canada

Robert J Zatorre
Neuropsychology/Cognitive Neuroscience Unit, Montreal Neurological Institute, Montreal, Canada

     Abstract ID Number: 174
     Full text: PDF
     Last modified: June 27, 2006
     Presentation date: 06/20/2006 10:00 AM in Hamilton Building, Foyer
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Abstract
Recent neuroimaging evidence suggests that exposure to only the visual component of words and musical notes can lead to activation of auditory areas, while familiar voices cause activation in the visual areas. In the present study we hypothesized that cross-modal cortical recruitment would occur when stimuli had been pre-associated.
In condition 1, 13 healthy participants were exposed to simultaneous sequences of white-noise bursts and green LED flashes for 45 minutes while making perceptual unity judgments. On a subsequent day, the same participants underwent PET scans whereby they were exposed to either the visual or the auditory component of the bimodal stimuli in separate scans. In condition 2, the same auditory or visual stimuli as the first group were presented to a second group of participants, who had not been exposed to the simultaneous bimodal presentation.
When presented with auditory or visual components of the bimodal stimuli alone, naïve subjects showed only modality-specific activation of cortical regions. However, subjects in condition 1 showed both cross-modal and modality-specific cortical regions in response to unimodal stimulus presentations. Thus, the association between auditory and visual stimuli carried was sufficient to produce activation in one sensory cortex when only the other modality was physically present.