【摘要】 实验在筒箭毒制动和人工呼吸维持下的清醒家兔上进行.用玻璃微电极在丘脑腹后外侧核(VPL)记录正中神经和腓神经刺激所引起的单位反应。Ⅰ、Ⅱ、Ⅲ、Ⅳ类纤维的传入冲动能特异地分别激活VPL内不同的神经元;这四类纤维的传入冲动能非特异地激活另一些神经元—R神经元。能被Ⅱ类纤维激活的14个βγ神经元和R神经元的活动不受对侧同名神经Ⅱ和Ⅳ类纤维条件刺激的影响;但对侧同名神经Ⅱ和Ⅳ类纤维的条件刺激对那些能被Ⅳ类纤维激活的C神经元和R神经元的活动有显著的抑制作用,使其长潜伏期的第二串放电的频率和时程减低。更多还原

【Abstract】 Experiments were carried out on rabbits immobilized with tubocurarine under artificial respiration. Single unit responses in the ventroposterior lateral nucleus(VPL) to electrical stimulation of the median and peroneal nerves were recorded with glass micropipettes. The afferent impulses were monitored by recording the action potential from the peripheral nerve trunk. The different types of thalamic neurons were identified by unit discharge in response to stimulation of various types of afferent fibers. A conditioning and testing stimulation technique was used to study the interaction of afferent inputs in VPL. The main results are as follows:1. The threshold for maximum excitation in group Ⅰ, Ⅱ, Ⅲ, and Ⅳ fibers were found to be 2.3, 9.3, 38.0, and 96.0 T respectively when the threshold of initial excitation of group I fibers was taken as 1 T. The maximum afferent inputs of group Ⅰ, Ⅱ, Ⅲ, or Ⅳ fibers could specifically activate different neurons in VPL, namely α,βγ, δ, and C neurons, while R neurons in VPL could be activated by the inputs of all these 4 groups of fibers. Among the 126 neurons studied, the numbers of α, βγ, δ, C, and R neurons identified were 41, 55, 16, 10, and 4 respectively.2. The activities of all the 14 βγ thalamic neurons and R neurons evoked by group Ⅱ fiber inputs could not be modulated by the conditioning afferent inputs from both group Ⅱ and Ⅳ fibers in contralateral homonymous nerves while the same conditioning afferent inputs could significantly suppress the activities of the C neurons as well as R neurons provoked by group Ⅳ fibers inputs. The suppression was characterized by decrease in discharge frequency and shortening in duration of the long latency second burst discharges.更多还原