Role of the nucleus geniculatus lateralis ventralis (GLv) in the optokinetic reflex: a lesion study in the pigeon
Role of the nucleus geniculatus lateralis ventralis (GLv) in the optokinetic reflex: a lesion study in the pigeon
复制标题
外侧膝状腹侧核 (GLv) 在视动反射中的作用：鸽子损伤研究
作者：
H. Gioanni;A. Palacios;A. Sansonetti;F. Varela
概述已经提出了几个功能的鸟类GLv（色觉，瞳孔反射，optomotor机制）。在本论文中，我们已经研究的作用，在视动反应的GLv。为此目的，水平和垂直视动性眼震（OKN）进行了量化，在不同的刺激速度，化学（海酸）病变之前和之后。单侧病变的GLv产生了显着增加的水平OKN增益时，病变对侧的眼睛在颞鼻（T-N）方向刺激，并在较小程度上，当同侧的眼睛在鼻颞（N-T）方向刺激。损伤后双眼整合减少，因为对应于这两个单眼刺激的双眼刺激（与损伤同侧）仅产生适度的增益增加。当刺激在相反的方向上（与病变相反）时，水平OKN增益对于病变对侧眼睛的N-T单眼刺激略有增加，但对于其他刺激没有变化。双侧病变的GLv引起的水平OKN增益只有轻微的增加。垂直方向OKN不受GLv病变的影响。因此，GLv系统可能参与调节视动反应，并可能介导视动相互作用，每个核（及其相关系统）在一个方向上对水平OKN施加抑制（或阻碍）作用。
SummarySeveral functions have been proposed for the avian GLv (color vision, pupillary reflex, optomotor mechanisms). In the present paper we have examined the role of the GLv in optomotor responses. For this purpose, horizontal and vertical optokinetic nystagmus (OKN) were quantified in response to different stimulation velocities, before and after chemical (kaïnic acid) lesions. Unilateral lesion of the GLv produced a marked increase of the horizontal OKN gain when the eye contralateral to the lesion was stimulated in the temporonasal (T-N) direction and, to a lesser extent, when the ipsilateral eye was stimulated in the naso-temporal (N-T) direction. Biocular integration was reduced after the lesion, since the biocular stimulation corresponding to these two monocular stimulations (ipsiversive to the lesion) produced only a moderate gain increase. When stimulations were delivered in the opposite direction (contraversive to the lesion), the horizontal OKN gain was slightly increased for the N-T monocular stimulation of the eye contralateral to the lesion, but was unchanged for other stimulations. A bilateral lesion of the GLv provoked only a slight increase of the horizontal OKN gain. The vertical OKN was not affected by the GLv lesions. Thus, the GLv system is probably involved in the modulation of optomotor responses and could mediate visuo-optokinetic interactions, each nucleus (and its associated system) exerting an inhibitory (or disfacilitatory) effect on the horizontal OKN in one direction.