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Is there a role of visual cortex in spatial hearing?

Authors

  • Ulrike Zimmer,

    1. Section Neuropsychology, Department of Cognitive Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
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  • Jörg Lewald,

    1. Leibniz Research Centre for Working Environment and Human Factors, Institute for Occupational Physiology at the University of Dortmund, Dortmund, Germany
    2. Department of Cognitive and Environmental Psychology, Ruhr University, Bochum, Germany
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  • Michael Erb,

    1. Section Experimental MR of the CNS, Department of Neuroradiology, University of Tübingen, Tübingen, Germany
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  • Wolfgang Grodd,

    1. Section Experimental MR of the CNS, Department of Neuroradiology, University of Tübingen, Tübingen, Germany
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  • Hans-Otto Karnath

    1. Section Neuropsychology, Department of Cognitive Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
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: Professor H.-O. Karnath, as above.
E-mail: karnath@uni-tuebingen.de

Abstract

The integration of auditory and visual spatial information is an important prerequisite for accurate orientation in the environment. However, while visual spatial information is based on retinal coordinates, the auditory system receives information on sound location in relation to the head. Thus, any deviation of the eyes from a central position results in a divergence between the retinal visual and the head-centred auditory coordinates. It has been suggested that this divergence is compensated for by a neural coordinate transformation, using a signal of eye-in-head position. Using functional magnetic resonance imaging, we investigated which cortical areas of the human brain participate in such auditory–visual coordinate transformations. Sounds were produced with different interaural level differences, leading to left, right or central intracranial percepts, while subjects directed their gaze to visual targets presented to the left, to the right or straight ahead. When gaze was to the left or right, we found the primary visual cortex (V1/V2) activated in both hemispheres. The occipital activation did not occur with sound lateralization per se, but was found exclusively in combination with eccentric eye positions. This result suggests a relation of neural processing in the visual cortex and the transformation of auditory spatial coordinates responsible for maintaining the perceptual alignment of audition and vision with changes in gaze direction.

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