Olausson B, Shyu B C, Rydenhag B
Department of Physiology, University of Göteborg, Sweden.
Exp Brain Res. 1990;79(3):515-29. doi: 10.1007/BF00229321.
Responses of cells in the midsuprasylvian gyrus (MSSG) of cats were investigated following electrical stimulation of the central lateral nucleus (CL) of the thalamus and tooth pulp, low-threshold cutaneous or visual afferents. Electrical stimulation in CL induced excitation in many cells located in cortical areas 5 and 7. Cells in these areas also received input from somato-sensory and visual afferents. Cells in MSSG showed a wide convergence from tooth pulp, low-threshold cutaneous afferents and from the CL. The majority of wide convergent cells in area 5 were found in layers IV and V, while cells excited by CL and tooth pulp were found in layers II and III. Similarities were found between CL and tooth pulp evoked responses with regard to the excitation-inhibition pattern. The excitation evoked from CL and tooth pulp was less often followed by a hyperpolarizing potential compared to that seen after low-threshold lip, paw and visual afferent stimulation. Stimulation sites in the lateral parts of CL-evoked responses with the shortest latencies in area 5. In this part of the cortex, short latency synaptic potentials were found in cells in superficial layers. In the same area, synaptic potentials of short latency were also evoked by electrical stimulation of tooth pulp, lip and paw. Light-flash stimulation evoked responses with the shortest latencies in area 7. The results of this study demonstrate that putative nociceptive information reaches the parietal association cortex and that part of this input may be relayed via CL. We suggest that the excitatory influences of nociceptive and CL stimulation is related to behavioral arousal and attention mechanisms.
在对猫的丘脑中央外侧核（CL）、牙髓、低阈值皮肤或视觉传入神经进行电刺激后，研究了猫中颞上回（MSSG）细胞的反应。CL中的电刺激在位于皮层5区和7区的许多细胞中诱发了兴奋。这些区域的细胞也接受来自体感和视觉传入神经的输入。MSSG中的细胞显示出来自牙髓、低阈值皮肤传入神经和CL的广泛汇聚。5区中大多数广泛汇聚的细胞位于IV层和V层，而由CL和牙髓兴奋的细胞位于II层和III层。在CL和牙髓诱发的反应之间，在兴奋-抑制模式方面发现了相似之处。与低阈值唇部、爪子和视觉传入神经刺激后相比，CL和牙髓诱发的兴奋较少随后出现超极化电位。CL外侧部分的刺激位点在5区诱发的反应潜伏期最短。在皮层的这一部分，表层细胞中发现了短潜伏期的突触电位。在同一区域，牙髓、唇部和爪子的电刺激也诱发了短潜伏期的突触电位。闪光刺激在7区诱发的反应潜伏期最短。这项研究的结果表明，假定的伤害性信息到达顶叶联合皮层，并且该输入的一部分可能通过CL中继。我们认为，伤害性刺激和CL刺激的兴奋性影响与行为唤醒和注意力机制有关。
