Lam K, Kakigi R, Mukai T, Yamasaki H
Department of Integrative Physiology, National Institute for Physiological Sciences, Okazaki, Japan.
Neuroscience. 2001;104(3):689-703. doi: 10.1016/s0306-4522(01)00101-4.
In our previous study, continuous visual (cartoon and random dot motion) and auditory (music) stimulation changed the somatosensory evoked magnetic fields following electrical stimulation of the median nerve in human subjects. They enhanced the middle-latency components (3M and 4M) generated in the contralateral primary somatosensory cortex, and reduced the MI component generated in the ipsilateral secondary somatosensory cortex. We speculated that such interference effects were caused by activation of polymodal neurons in areas 5 and/or 7 of the parietal lobe as well as in the medial superior temporal region and superior temporal sulcus. However, we could not exclude the effect of attention on such interference effects. In the present study, to know the effect of attention on visual and auditory interference in these changes, we stimulated the bilateral median nerves unilaterally in a random order, and asked subjects to count the number of times the left median nerve was stimulated while visual or auditory interference was applied. Five components (1M-5M) were identified in the hemisphere contralateral to the stimulated nerve and only one component (MI) was found in the ipsilateral hemisphere. The 3M and 4M components (33-75 ms in latency) were enhanced by both attention and visual interference stimulation but not by auditory stimulation. The 5M component (70-115 ms) and MI component (70-133 ms) were enhanced by attention, but were not changed by attention together with visual or auditory interference. Summarizing the results of our previous study and the present study, (1) visual interference alone enhanced the 3M and 4M but reduced the MI, and (2) attention alone also enhanced the 3M and 4M, and enhanced the 5M and MI. As a result, (3) visual interference with attention enhanced the 3M and 4M more, and showed no significant change of the 5M and MI. This was compatible with a summation of the effects caused by visual interference alone and attention alone, but some interactions between visual interference and attention might have taken place. The locations of dipoles of all components were not significantly changed by attention or any interference stimulation. These findings support the idea that there are significant interactions of activities relating to somatosensory stimulation, visual stimulation and cognitive function, in both the primary and the secondary somatosensory cortex in humans.
在我们之前的研究中，持续的视觉（卡通和随机点运动）和听觉（音乐）刺激改变了人类受试者正中神经电刺激后的体感诱发磁场。它们增强了对侧初级体感皮层产生的中潜伏期成分（3M和4M），并减少了同侧次级体感皮层产生的MI成分。我们推测这种干扰效应是由顶叶5区和/或7区以及内侧颞上区和颞上沟中的多模式神经元激活引起的。然而，我们不能排除注意力对这种干扰效应的影响。在本研究中，为了了解注意力对这些变化中视觉和听觉干扰的影响，我们以随机顺序单侧刺激双侧正中神经，并要求受试者在施加视觉或听觉干扰时计算左侧正中神经被刺激的次数。在受刺激神经对侧的半球中识别出五个成分（1M - 5M），而在同侧半球中仅发现一个成分（MI）。3M和4M成分（潜伏期为33 - 75毫秒）在注意力和视觉干扰刺激下均增强，但在听觉刺激下未增强。5M成分（70 - 115毫秒）和MI成分（70 - 133毫秒）在注意力作用下增强，但在注意力与视觉或听觉干扰共同作用时未发生变化。总结我们之前研究和本研究的结果，（1）单独的视觉干扰增强了3M和4M，但降低了MI，并且（2）单独注意力也增强了3M和4M，以及增强了5M和MI。结果，（3）注意力与视觉干扰一起增强3M和4M的程度更大，并且5M和MI没有显著变化。这与单独视觉干扰和单独注意力所产生的效应的总和相符，但视觉干扰和注意力之间可能发生了一些相互作用。所有成分的偶极子位置在注意力或任何干扰刺激下均未发生显著变化。这些发现支持了这样一种观点，即人类初级和次级体感皮层中与体感刺激、视觉刺激和认知功能相关的活动存在显著的相互作用。
