Aloisi A M, Decchi B, Fontani G, Rossi A, Carli G
Istituto di Fisiologia Umana, Università degli Studi di Siena, Italy.
Somatosens Mot Res. 1996;13(3-4):263-71. doi: 10.3109/08990229609052582.
The contribution of joint afferents to the response of cortical neurons in area 3a to mechanical stimulation of the contralateral hindlimb was evaluated in cats anesthetized with sodium pentobarbital and paralyzed with pancuronium bromide. The hindlimb projection to the pericruciate cortex was established by recording the evoked potentials to electrical stimulation of the sciatic nerve and some of its branches, the bicepssemitendinosus and the quadratus femoris. Out of 169 neurons, 63 responded exclusively to cutaneous stimuli (superficial), whereas the others could be activated by local pressure of hindlimb muscles and/or by joint rotation (deep). Deep neurons were classified as slowly adapting (SA) or rapidly adapting (RA) units. In the neurons responding exclusively to joint rotation, the site of the receptive field could not be identified with certainty. In 13 deep neurons, their firing was affected by rotation of multiple joints of the contralateral hindlimb. In an attempt to identify the source of activation of cortical neurons, partial denervations and muscle disconnections were performed in five animals to isolate and stimulate the hip capsule. In these preparations, in 14 of 15 cortical neurons the source of activation was localized in the periarticular muscles, with no response to mechanical stimulation of the joint capsule. Only one neuron (SA) could be selectively excited by punctate pressure on the hip capsule. Our results suggest that in neurons of area 3a of the cat, the information about the position of the femur relies mainly on muscle afferents.
在戊巴比妥钠麻醉并用泮库溴铵麻痹的猫中，评估了关节传入神经对3a区皮质神经元对侧后肢机械刺激反应的贡献。通过记录坐骨神经及其一些分支（半腱肌和股方肌）电刺激诱发的电位，建立了后肢向十字周皮质的投射。在169个神经元中，63个仅对皮肤刺激（浅表刺激）有反应，而其他神经元可被后肢肌肉的局部压力和/或关节旋转（深部刺激）激活。深部神经元分为慢适应性（SA）或快适应性（RA）单位。在仅对关节旋转有反应的神经元中，感受野的位置无法确切确定。在13个深部神经元中，它们的放电受对侧后肢多个关节旋转的影响。为了确定皮质神经元的激活来源，对5只动物进行了部分去神经支配和肌肉切断，以分离并刺激髋关节囊。在这些标本中，15个皮质神经元中有14个的激活来源定位于关节周围肌肉，对关节囊的机械刺激无反应。只有一个神经元（SA）能被髋关节囊上的点状压力选择性兴奋。我们的结果表明，在猫的3a区神经元中，关于股骨位置的信息主要依赖于肌肉传入神经。
