Tanosaki Masato, Iguchi Yoshinobu, Kimura Tomoaki, Takino Ryosuke, Hashimoto Isao
Third Department of Internal Medicine, Hirosaki University School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori 036-8562, Japan.
Clin Neurophysiol. 2004 Nov;115(11):2638-44. doi: 10.1016/j.clinph.2004.05.020.
We compared the effects of tactile interference to the forearm on magnetic responses evoked by electric stimulation of the little finger (D5) and the thumb (D1).
Electric stimulation was delivered to D5 or D1 individually. In each stimulus session, magnetic recordings were conducted with or without concurrent tactile interference to the radial side of the anterior forearm.
With forearm interference, the amplitude of the primary response (N20m) following D5 stimulation was reduced to 90.7% of the control value without interference, while that following D1 stimulation was not affected (100.7%).
In human somatosensory area 3b, the representation of the forearm is immediately adjacent to that of the D5, and distant from that of the D1. Thus, the result suggests that the tactile interference effect on N20m depends on the cortical distance between electrically and mechanically activated 3b areas.
Intrinsic synaptic connections between the 3b hand representation and its surroundings have been hypothesized as a neural basis for plastic changes of the human brain, such as a phantom hand phenomenon. The present finding implies that these connections may play some physiological roles even in normal adult humans.
我们比较了对前臂的触觉干扰对小指（D5）和拇指（D1）电刺激诱发的磁反应的影响。
分别对D5或D1进行电刺激。在每次刺激过程中，在前臂桡侧有或无同时进行触觉干扰的情况下进行磁记录。
在前臂有干扰时，D5刺激后初级反应（N20m）的幅度降至无干扰时对照值的90.7%，而D1刺激后的初级反应幅度未受影响（100.7%）。
在人类体感区3b中，前臂的代表区紧邻D5的代表区，而与D1的代表区距离较远。因此，该结果表明对N20m的触觉干扰效应取决于电激活和机械激活的3b区之间的皮质距离。
3b手部代表区与其周围区域之间的内在突触连接被认为是人类大脑可塑性变化（如幻手现象）的神经基础。目前的发现意味着这些连接即使在正常成年人中也可能发挥一些生理作用。
