Hine Jemma, Debener Stefan
Medical Research Council, Institute of Hearing Research, Royal South Hants Hospital, Southampton, UK.
Clin Neurophysiol. 2007 Jun;118(6):1274-85. doi: 10.1016/j.clinph.2007.03.012. Epub 2007 Apr 25.
To investigate brain asymmetries of the auditory evoked potential (AEP) N100, T-complex, and P200 in response to monaural stimulation.
Electroencephalographic (EEG) recordings from 68 channels were used to record auditory cortex responses to monaural stimulation from normal hearing participants (N=16). White-noise stimuli and 1000Hz tones were repeatedly presented to either the left or right ear. Source localization of the AEP N100 response was carried out with two symmetric regional sources placed into left and right auditory cortex. Regional source waveform amplitude and latency asymmetries were analyzed for tangential and radial activity explaining the N100, T-complex and P200 AEP components.
Regional source waveform analysis showed that early tangential activity in the N100 latency range exhibited larger contralateral amplitudes and shorter latencies for both tone and noise monaural stimuli. Lateralized activity was significantly greater when tones or noise was presented to the left compared to the right ear (p<.001). The ear difference in the degree of lateralization arose due to hemispheric asymmetry. Significantly more tangential activity in the N100 latency range was recorded in the right compared to the left hemisphere in response to stimulation by either tones or noise (p<.001). Neither the radial activity modelling the T-complex, nor activity modelling the P200, showed robust ear or hemisphere differences.
Regional source waveform analysis revealed that the extent of auditory evoked potential asymmetries depends on the ear and hemisphere examined. These findings have implications for future studies utilizing AEP asymmetries to examine normal auditory function or experience-related changes in the auditory cortex.
The right compared to the left auditory cortex may be more involved in processing monaurally presented tone and noise stimuli.
研究单耳刺激时听觉诱发电位（AEP）N100、T复合波和P200的脑不对称性。
使用来自68个通道的脑电图（EEG）记录，记录正常听力参与者（N = 16）对单耳刺激的听觉皮层反应。白噪声刺激和1000Hz纯音反复呈现给左耳或右耳。AEP N100反应的源定位是通过将两个对称的区域源置于左右听觉皮层来进行的。分析区域源波形幅度和潜伏期不对称性，以解释N100、T复合波和P200 AEP成分的切向和径向活动。
区域源波形分析表明，在N100潜伏期范围内的早期切向活动，对于纯音和噪声单耳刺激，对侧幅度更大，潜伏期更短。与右耳相比，当向左耳呈现纯音或噪声时，侧化活动明显更大（p<.001）。侧化程度的耳差异是由于半球不对称引起的。与左半球相比，在对纯音或噪声刺激的反应中，右半球在N100潜伏期范围内记录到的切向活动明显更多（p<.001）。模拟T复合波的径向活动和模拟P200的活动均未显示出明显的耳或半球差异。
区域源波形分析表明，听觉诱发电位不对称的程度取决于所检查的耳和半球。这些发现对未来利用AEP不对称性来研究正常听觉功能或听觉皮层中与经验相关变化的研究具有启示意义。
与左听觉皮层相比，右听觉皮层可能更多地参与处理单耳呈现的纯音和噪声刺激。
