[Response and membrane properties of nociceptive neurons in SI to stimulation of VPL].

Intracellular potentials were recorded from nociceptive neurons(NCNs) in primary somatosensory cortex area (SI) of cats in response to stimulation of ventral posterior lateral nucleus (VPL). When the polarizing current injected into NCNs was < or = 1.0 nA, the I-V curve was quite linear (r=0.96). However, when the polarizing current was >1.0 nA, rectification rendered the I-V curve sigmoid in shape. The rectification in NCNs was more prominent than that in NNCNs. Rm,tau and Cm of the NCNs were obviously larger than those of NNCNs (P<0.01 or P<0.05). The responses of NCNs evoked by stimulating VPL and SN might be similar or different. Implications of the differences of NCN and NNCN were discussed.