Forss N, Hari R, Salmelin R, Ahonen A, Hämäläinen M, Kajola M, Knuutila J, Simola J
Low Temperature Laboratory (LTL), Helsinki University of Technology, Espoo, Finland.
Exp Brain Res. 1994;99(2):309-15. doi: 10.1007/BF00239597.
We recorded somatosensory evoked magnetic fields from ten healthy, right-handed subjects with a 122-channel whole-scalp SQUID magnetometer. The stimuli, exceeding the motor threshold, were delivered alternately to the left and right median nerves at the wrists, with interstimulus intervals of 1, 3, and 5 s. The first responses, peaking around 20 and 35 ms, were explained by activation of the contralateral primary somatosensory cortex (SI) hand area. All subjects showed additional deflections which peaked after 85 ms; the source locations agreed with the sites of the secondary somatosensory cortices (SII) in both hemispheres. The SII responses were typically stronger in the left than the right hemisphere. All subjects had an additional source, not previously reported in human evoked response data, in the contralateral parietal cortex. This source was posterior and medial to the SI hand area, and evidently in the wall of the postcentral sulcus. It was most active at 70-110 ms.
我们使用122通道全头超导量子干涉仪磁力计，记录了10名健康右利手受试者的体感诱发磁场。刺激强度超过运动阈值，交替施加于双侧手腕的正中神经，刺激间隔分别为1秒、3秒和5秒。最初的反应在20毫秒和35毫秒左右达到峰值，这是由对侧初级体感皮层（SI）手部区域的激活所解释的。所有受试者均表现出额外的偏转，其峰值出现在85毫秒之后；源定位与双侧半球的次级体感皮层（SII）位置一致。SII反应通常在左侧半球比右侧半球更强。所有受试者在对侧顶叶皮层还有一个此前在人类诱发反应数据中未报道过的额外源。该源位于SI手部区域的后方和内侧，明显在中央后沟壁内。它在70 - 110毫秒时最为活跃。
