Inhibition of auditory cortical responses to ipsilateral stimuli during dichotic listening: evidence from magnetoencephalography
Inhibition of auditory cortical responses to ipsilateral stimuli during dichotic listening: evidence from magnetoencephalography
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DOI：
10.1111/j.0953-816x.2004.03302.x
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发表时间：
2004-04-01
影响因子：
3.4
通讯作者：
Rossini, PM
中科院分区：
文献类型：
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作者：
Brancucci, A;Babiloni, C;Rossini, PM
本脑磁图（MEG）对听觉诱发磁场（AEFs）的研究旨在验证在二元聆听过程中对侧听觉通路是否抑制同侧听觉通路，正如行为和患者研究所表明的那样。10名健康受试者随机接受三组复杂音调（261、293和391 Hz，持续时间500 ms），分别以不同强度（60、70或80 dBA）单、双音调传递。脑磁图数据记录于右侧听觉皮层。结果表明，当在同侧（右耳）提供强度增加的音调时，右侧听觉皮层的M100振幅逐渐增加。当在对侧（左）耳双向传递恒定强度的同步音调时，这种对M100的影响被消除，表明对侧通路抑制同侧通路。只有当对侧音基频与同侧音基频相似时，才会出现同侧抑制。由于在M100而非M50组分中观察到二元效应，因此提出了在皮质听觉区发挥闭塞机制的可能性。这是首次有证据表明，在双重聆听过程中，对侧听觉通路对同侧听觉通路有神经生理抑制作用。
The present magnetoencephalography (MEG) study on auditory evoked magnetic fields (AEFs) was aimed at verifying whether during dichotic listening the contralateral auditory pathway inhibits the ipsilateral one, as suggested by behavioural and patient studies. Ten healthy subjects were given a randomized series of three complex tones (261, 293 and 391 Hz, 500 ms duration), which were delivered monotically and dichotically with different intensities [60, 70 or 80 dBA (audio decibels)]. MEG data were recorded from the right auditory cortex. Results showed that the M100 amplitude over the right auditory cortex increased progressively when tones of increasing intensity were provided at the ipsilateral (right) ear. This effect on M100 was abolished when a concurrent tone of constant intensity was delivered dichotically at the contralateral (left) ear, suggesting that the contralateral pathway inhibited the ipsilateral one. The ipsilateral inhibition was present only when the contralateral tone fundamental frequency was similar to the ipsilateral tone. It was proposed that the occlusion mechanism would be exerted in cortical auditory areas as the dichotic effects were observed at M100 but not M50 component. This is the first evidence showing a neurophysiological inhibition driven by the contralateral auditory pathway over the ipsilateral one during dichotic listening.