我们曾报道

以极化电流阻断A类纤维的传导后

仅让C类纤维传入时

在对侧大脑皮层体感Ⅰ区(SI)记录到可反映慢反应的C类纤维皮层诱发电位(C-CEP);电刺激SI区的不同深度对C-CEP可产生不同程度的抑制作用。Dariansmith等曾确定猫大脑皮层的前上雪氏回为特异的体Experiments were performed on cats under chlorclose anaothesia and im-mobilized by gallaminc ethiodide. The saphenous nerve was stimulated with strongelectric pulses and the A-fibers were blocked by anodal current so as to exciteC-fibers selectively. The cortical potential evoked by C-fibers input (C-CFP)which was related to slow pain was recorded on the contralateral somatosensoryarea Ⅰ(SI). The different depths of SⅢ were stimulated with the electricpulses of different intensities and the effect of the stimulation on C-CEP wasobserved. The results showed when the SⅢ was stimulated

the amplitudes ofCCEP decreased and the after-effect might continue for 4 minutes. It showedthat the stimulation of SⅢ had aninhibitory effect on C-CEP. The inhibitoryeffect of SⅢ stimulation was stronger than that of stimulation was strongerSⅠ. The effect of stimulating superficial and deeper layers of SⅢ on C-CEPwas stronger than that of middle layers. When the deeper layers of SⅢ wasstimulated

the stronger the stimulating intensity was

the stronger the inhibitoryeffect of stimulating SⅢ was related to the intensily and the depth of stimula-tion. From the above results

it is suggested that SⅢ might participate in thenodulation of slow pain.