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Open AccessHighly AccessResearch article

Left hemispheric dominance during auditory processing in a noisy environment

Hidehiko Okamoto1,2,3 email, Henning Stracke1 email, Bernhard Ross2 email, Ryusuke Kakigi3 email and Christo Pantev1,2 email

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

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

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

author email corresponding author email

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

Published: 15 November 2007

Abstract

Background

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).

Results

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.

Conclusion

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.


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