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Advances in Sound Localization part 11

Tham khảo tài liệu 'advances in sound localization part 11', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 21 Neurophysiological Correlate of Binaural Auditory Filter Bandwidth and Localization Performance Studied by Auditory Evoked Fields Yoshiharu Soeta and Seiji Nakagawa National Institute of Advanced Industrial Science and Technology AIST Japan 1. Introduction Binaural hearing is specifically useful for our ability to separate a speech from a background noise and localize sounds. Binaural hearing performances are influenced by binaural auditory filter inteaural time delay ITD interaural correlation IAC and so on. Some psychological experiments have clarified binaural auditor filter bandwidths Kollmeier Holube 1989 Holube et al. 1998 and performance of sound localization related to ITD and IAC Mills 1958 Jeffress et al. 1962 . However little is known about the neural correlates which makes an important contribution to our understanding of the auditory system. Therefore we tried to estimate binaural auditory filter bandwidth and localization performance by the response in human auditory cortex. Frequency selectivity has an important role in many aspects of auditory perception. For example one sound may be obscured or rendered inaudible in the presence of other sounds. Frequency selectivity represents the ability of the auditory system to separate out or resolve the frequency components of a complex sound and can be characterized by the auditory filter bandwidths. Auditor filter bandwidths have been used to identify a fundamental perceptual unit that defines the frequency resolution of the auditory system - the critical bandwidth CBW . The critical band CB concept has been used to explain a wide range of perceptual phenomena involving complex sounds. Physiological correlates of the CBW have been described in several studies examining the auditory evoked potential AEP or auditory evoked field AEF in humans. Zerlin 1986 reported an abrupt increase in the amplitude of wave V of the brainstem AEP responses when the bandwidth of a two-tone complex approximated the CBW. .