Optokinetic nystagmus in the pigeon (Columba livia) II. Role of the pretectal nucleus of the accessory optic system (AOS)
Optokinetic nystagmus in the pigeon (Columba livia) II. Role of the pretectal nucleus of the accessory optic system (AOS)
复制标题
鸽子（Columba livia）的视动眼球震颤 II。
作者：
H. Gioanni;J. Rey;J. Villalobos;D. Richard;A. Dalbera
鸟类的副视系统（AOS）包括两个核团：外乳头核（nEM）和顶盖前浅合脑核（nSS）。通过比较单侧损伤此核前后的水平视动性眼震（OKN），研究了nSS在鸽子水平视动性眼震（OKN）产生中的作用。病变进行电解或局部应用红藻氨酸（KA），KA病变得到更稳定的修改OKN比电解病变。对接受KA损伤的动物进行OKN慢相速度（V）的定量分析。（1）nSS的损伤引起在颞鼻方向上刺激对侧眼的OKN几乎完全消失，并且在鼻颞方向上刺激的OKN减少。因此，nSS对于在颞-鼻方向上产生OKN是必不可少的，但它也参与在鼻-颞方向（慢相方向）上产生OKN。（2）当刺激同侧眼时，同一病变引起OKN（<$V）的大幅度增加，而刺激鼻颞方向时，OKN（<$V）的增加幅度较小。这些增加表明一侧的nSS（或相关系统）与对侧视动中心之间存在某种抑制性（或阻碍性）相互作用。（3）当刺激为双眼时，一个nSS的损害不会引起缺陷。这一结果可能反映了两个单眼输入的组合效果。（4）在顶盖前注射KA后，可以看到对侧眼在鼻颞方向上的自发性眼球震颤持续数小时。其机制尚不清楚，但可能与眼球震颤后的反向视动性（ROKAN）有关。
迄今为止的解剖学和生理学数据一致支持鸟类的nSS和哺乳动物的视束核之间的功能等效性的假设。
SummaryIn birds, the accessory optic system (AOS) includes two nuclei: the nucleus ectomamillaris (nEM) and the pretectal nucleus superficialis synencephali (nSS). The role of the nSS in the production of a horizontal optokinetic nystagmus (OKN) was studied in the pigeon, by comparing the OKN before and after a unilateral lesion of this nucleus. The lesions were performed either by electrolysis or by local application of kainic acid (KA); the KA lesions gave more stable modifications of the OKN than the electrolytic lesions. A quantitative analysis of the slow-phase velocity (¯V) of the OKN was carried out on the animals receiving KA lesions.(1)Lesion of the nSS provokes the almost total disappearance of the OKN for stimulation of the contralateral eye in the temporo-nasal direction, and a reduction of the OKN for stimulation in the nasotemporal direction. Thus, the nSS is essential for the production of the OKN in the temporo-nasal direction, but it also participates in the production of the OKN in the naso-temporal direction (slow-phase direction).(2)The same lesion produces a large increase of the OKN (¯V) when the ipsilateral eye is stimulated in the temporo-nasal direction, and a smaller increase following stimulation in the naso-temporal direction. These increases suggest some kind of inhibitory (or disfacilitatory) interactions between the nSS (or the associated system) on one side, and the contralateral optokinetic centers.(3)The lesion of one nSS does not provoke a deficit when the stimulation is binocular. This result probably reflects the combined effect of both monocular inputs.(4)After a pretectal KA injection, a spontaneous nystagmus of the contralateral eye, in the nasotemporal direction, can be seen for several hours. The mechanism is still unknown, but it might be rela2ted to a reverse optokinetic after nystagmus (ROKAN).
The anatomical and physiological data so far available consistently support the hypothesis of a functional equivalence between the nSS in birds and the nucleus of the optic tract in mammals.