Yvert B, Bertrand O, Pernier J, Ilmoniemi R J
BioMag Laboratory, Helsinki University Central Hospital, Finland.
Neuroreport. 1998 Apr 20;9(6):1115-9. doi: 10.1097/00001756-199804200-00029.
Behavioral and patient studies have suggested that during dichotic listening the ipsilateral auditory pathways are strongly inhibited, so that each hemisphere is treats the sound coming to the contralateral ear. We analysed the auditory N100m neuromagnetic evoked response following passive listening of dichotic tones of different frequencies. We found that the N100m in each hemisphere depended on both ipsilateral and contralateral stimuli, revealing no strong inhibition of ipsilateral pathways. The N100m increased with the interaural frequency disparity and was reduced as both ears received identical stimuli. The results can be explained by the existence of a frequency-dependent excitatory/inhibitory organization of the auditory cortex, as has been described in the cat. We suggest that the N100m might also reflect automatic processes involved in multiple-stream perception.
行为学和患者研究表明，在双耳分听过程中，同侧听觉通路会受到强烈抑制，从而使每个半球处理来自对侧耳朵的声音。我们分析了在被动聆听不同频率的双耳分听音调后，听觉N100m神经磁诱发反应。我们发现每个半球的N100m既依赖于同侧刺激，也依赖于对侧刺激，这表明同侧通路没有受到强烈抑制。N100m随着双耳频率差异的增加而增加，而当双耳接收到相同刺激时则会降低。这些结果可以通过猫身上所描述的听觉皮层中存在频率依赖性兴奋/抑制组织来解释。我们认为，N100m也可能反映了多流感知中涉及的自动过程。
