Wang Y, Xiao J, Wang S R
Laboratory for Visual Information Processing, Institute of Biophysics, Chinese Academy of Sciences, Beijing.
J Comp Physiol A. 2000 Jun;186(6):505-11. doi: 10.1007/s003590000102.
It has been known that magnocellular and parvocellular divisions of the pigeon nucleus isthmi exert excitatory and inhibitory actions on tectal cells, respectively. The present study shows that injection of N-methyl-D-aspartate into the parvocellular division results in an increase in responsive strength and extent of the inhibitory receptive fields, which expand into the excitatory receptive fields of tectal cells. This injection concurrently leads to a decrease in responsiveness and extent of the excitatory fields. On the other hand, injection of acetylcholine into the magnocellular division enhances visual responsiveness, although the excitatory field is not obviously changed in extent. Meanwhile, strength and extent of the inhibitory fields are decreased by acetylcholine. The excitatory and inhibitory fields are reduced in both strength and extent by magnocellular and parvocellular injection of lidocaine, respectively. It suggests that isthmic inputs from both parvocellular and magnocellular divisions converge onto the same tectal cells, and the magnocellular and parvocellular subnuclei can modulate excitatory and inhibitory receptive fields of tectal cells, respectively, with some interactions between both fields.
已知鸽子峡核的大细胞部和小细胞部对顶盖细胞分别发挥兴奋作用和抑制作用。本研究表明，向小细胞部注射N-甲基-D-天冬氨酸会导致抑制性感受野的反应强度和范围增加，抑制性感受野会扩展到顶盖细胞的兴奋性感受野中。这种注射同时会导致兴奋性感受野的反应性和范围降低。另一方面，向大细胞部注射乙酰胆碱会增强视觉反应性，尽管兴奋性感受野的范围没有明显变化。同时，乙酰胆碱会使抑制性感受野的强度和范围减小。分别向大细胞部和小细胞部注射利多卡因会使兴奋性和抑制性感受野的强度和范围都减小。这表明来自小细胞部和大细胞部的峡核输入汇聚到相同的顶盖细胞上，并且大细胞亚核和小细胞亚核可以分别调节顶盖细胞的兴奋性和抑制性感受野，且两个感受野之间存在一些相互作用。
