Brain Research Unit, Low Temperature Laboratory, Helsinki University of Technology, FIN-02015 Espoo, Finland.
Cereb Cortex. 2010 Aug;20(8):1898-903. doi: 10.1093/cercor/bhp260. Epub 2009 Dec 3.
Controversy persists over the role of the primary somatosensory cortex (SI) in processing small-fiber peripheral afferent input. We therefore examined subject I.W, who, due to sensory neuronopathy syndrome, has no large-fiber afferents below C3 level. Cortical evoked responses were recorded with a whole-scalp neuromagnetometer to high-intensity electrical stimulation of the distal right radial, median, and tibial nerves and skin over the forearm and mechanical stimulation of (neurologically intact) lip. The responses to electrical stimulation in the Abeta-denervated limbs peaked at 110-140 ms in contralateral SI and at 140-220 ms in contralateral secondary somatosensory cortex (SII), consistent with Adelta-mediated input. I.W. was able to localize pin-prick stimuli with 4 cm accuracy. Responses to laser stimuli on the radial dorsum of the hand peaked in contralateral SII cortex at 215 ms, also compatible with Adelta-mediated input. These results support the role of the SI cortex in processing the sensory discriminative aspects of Adelta-mediated input.
关于初级体感皮层（SI）在处理小纤维外周传入输入方面的作用一直存在争议。因此，我们检查了患者 I.W.，由于感觉神经元病综合征，他的 C3 以下没有大纤维传入。使用全头皮神经磁力计记录皮质诱发反应，对右侧远端桡骨、正中神经和胫骨的高强度电刺激以及前臂皮肤和（神经完整）唇部的机械刺激。在去神经支配的肢体中，电刺激的反应在对侧 SI 中在 110-140ms 处达到峰值，在对侧次级体感皮层（SII）中在 140-220ms 处达到峰值，与 Adelta 介导的输入一致。I.W.能够以 4 厘米的精度定位刺痛刺激。在手背的桡骨侧的激光刺激的反应在对侧 SII 皮层在 215ms 处达到峰值，这也与 Adelta 介导的输入一致。这些结果支持 SI 皮层在处理 Adelta 介导的输入的感觉辨别方面的作用。
