Human frequency-following responses to binaural masking level difference stimuli.
Human frequency-following responses to binaural masking level difference stimuli.
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DOI：
10.3766/jaaa.16.3.6
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发表时间：
2005-03
影响因子：
1.2
通讯作者：
James R. Wilson;A. Krishnan
中科院分区：
文献类型：
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作者：
James R. Wilson;A. Krishnan
双耳掩蔽水平差是双耳状态（SoNo）和双耳状态（SoNpi）之间的行为阈值差，其中信号（SpiNo）或掩蔽器（SoNpi）的耳间相位延迟为180度。阈值差异部分与内侧上橄榄的重合检测单元有关，该单元对低频双耳刺激具有耳间相位差异。先前的表面诱发电位研究报道了SpiNo刺激与SoNo刺激在P1-N1听觉事件相关电位上的潜伏期和振幅存在显著差异，但没有研究报道脑干诱发电位的生理掩膜水平差异。人类频率跟随反应（FFR）代表了脑干上部低频锁相神经单元的活动。记录了9名听力正常的成人受试者在500 Hz频响和1.5 kHz低通频响前的ffr。SoNo条件下FFR幅值显著降低，且掩蔽强度接近心理声SoNo掩蔽水平。SoNpi和SpiNo条件下均观察到显著的FFR振幅恢复。这些结果支持锁相神经活动在参与知觉掩蔽释放的脑干机制中的作用。
Binaural masking level difference is the behavioral threshold difference between a diotic condition (SoNo) and a dichotic condition with a 180 degrees interaural phase delay of either the signal (SpiNo) or the masker (SoNpi). Threshold disparity is partially related to coincidence-detecting units in the medial superior olive that are sensitive to low-frequency binaural stimuli with interaural phase differences. Previous surface evoked potential studies report significant latency and amplitude differences to SpiNo stimuli with respect to SoNo stimuli in the P1-N1 auditory event related potential, but no study has reported physiologic masking level differences in a brain stem evoked potential. The human frequency-following response (FFR) represents activity from low-frequency, phase locking neural units in the upper brainstem. Unmasked FFRs to 500 Hz tone bursts and masked FFRs using a 1.5 kHz low-pass masker were recorded from nine normal-hearing adult subjects. Significant reduction in FFR amplitude occurred in the SoNo condition, re the So condition, with masker intensities near the psychoacoustic SoNo masking level. Significant FFR amplitude recovery was observed for both the SoNpi and SpiNo conditions. These results support the role of phase-locked neural activity in brainstem mechanisms involved in perceptual masking release.