Wang B, Hu C H
Department of Biology, Southwest-China Teachers University, Chongqing.
Sheng Li Xue Bao. 1993 Apr;45(2):172-7.
Discharges of 88 somatosensory units in the nucleus dorsalis intermedius ventralis anterior thalami (DIVA) in response to afferent impulses of radial nerve on 55 urethane anesthetized pigeons were recorded and analysed. Among the 88 units, part of them also responded to the stimulation of sciatic nerve. Following electrical stimulation of somatic projecting area of hyperstriatum, the spontaneous discharges and the responses of DIVA somatosensory units to radial inputs were obviously inhibited and the degree of inhibition was linearly correlated with the frequency and intensity of stimulation. The inhibitory effect on the responses to radial inputs may cause an increase in latency and a decrease in number of spikes. These results indicate that the DIVA certainly belongs to somatosensory system, and the somatic projecting area of hyperstriatum has a descending inhibitory effect on the DIVA somatosensory units. The hyperstriatum may thus exert feedback control over its sensory inputs through descending inhibition. It appears that the functional connection between the highest region of central nervous system and thalamus in avian is similar to that of mammal.
记录并分析了55只经乌拉坦麻醉的鸽子丘脑背内侧中间腹侧核（DIVA）中88个体感单位对桡神经传入冲动的放电情况。在这88个单位中，部分单位也对坐骨神经刺激有反应。在对纹状体超层体的躯体投射区进行电刺激后，DIVA体感单位的自发放电以及对桡神经传入的反应明显受到抑制，且抑制程度与刺激频率和强度呈线性相关。对桡神经传入反应的抑制作用可能导致潜伏期延长和放电峰值数量减少。这些结果表明，DIVA肯定属于体感系统，纹状体超层体的躯体投射区对DIVA体感单位具有下行抑制作用。因此，纹状体超层体可能通过下行抑制对其感觉输入进行反馈控制。看来鸟类中枢神经系统最高区域与丘脑之间的功能联系与哺乳动物相似。
