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Open Access Highly Accessed Research article

Left hemispheric dominance during auditory processing in a noisy environment

Hidehiko Okamoto123, Henning Stracke1, Bernhard Ross2, Ryusuke Kakigi3 and Christo Pantev12*

Author Affiliations

1 Institute for Biomagnetism and Biosignalanalysis, University of Muenster, Muenster, Germany

2 Rotman Research Institute at Baycrest Centre, University of Toronto, Ontario, Canada

3 Department of Integrative Physiology, National Institute for Physiological Sciences, Okazaki, Japan

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BMC Biology 2007, 5:52  doi:10.1186/1741-7007-5-52

Published: 15 November 2007



In daily life, we are exposed to different sound inputs simultaneously. During neural encoding in the auditory pathway, neural activities elicited by these different sounds interact with each other. In the present study, we investigated neural interactions elicited by masker and amplitude-modulated test stimulus in primary and non-primary human auditory cortex during ipsi-lateral and contra-lateral masking by means of magnetoencephalography (MEG).


We observed significant decrements of auditory evoked responses and a significant inter-hemispheric difference for the N1m response during both ipsi- and contra-lateral masking.


The decrements of auditory evoked neural activities during simultaneous masking can be explained by neural interactions evoked by masker and test stimulus in peripheral and central auditory systems. The inter-hemispheric differences of N1m decrements during ipsi- and contra-lateral masking reflect a basic hemispheric specialization contributing to the processing of complex auditory stimuli such as speech signals in noisy environments.