McConville K, Tomlinson R D, King W M, Paige G, Na E Q
Department of Physiology, University of Toronto, Ontario, Canada.
J Vestib Res. 1994 Sep-Oct;4(5):391-400.
Recordings from neurons in the vestibular nuclei indicate that the cells that carry eye position signals encode the position of a single eye (either ipsilateral or contralateral) during both conjugate and vergence eye movements. The fact that the vestibular nuclei are aware of the positions of each eye is not surprising as the otolith-based linear vestibulo-ocular reflex is known to change its behaviour as a function of uniocular eye position. This result suggests that the signal coming from the oculomotor velocity-to-position integrator specifies the position of each eye during vergence movements and thus must receive a vergence velocity input along with its conjugate velocity inputs. As there is no vergence system in laterally eyed animals, we have proposed two possible models of integrator arrangement that could have developed from conjugate directional (rather than uniocular) integrators in lower animals without frontally mounted eyes. Both of these models explain the existence of near-response cells and produce the required bidirectional gaze paretic nystagmus following unilateral lesions of one integrator. The models also make specific and different predictions concerning the effects of unilateral integrator lesions on the behaviour of the vergence system and thus make suggestions for further experiments.
来自前庭核中神经元的记录表明，在共轭和聚散眼球运动过程中，携带眼位信号的细胞编码单眼（同侧或对侧）的位置。前庭核知晓每只眼睛的位置这一事实并不奇怪，因为基于耳石的线性前庭眼反射已知会根据单眼眼位改变其行为。这一结果表明，来自动眼速度到位置积分器的信号在聚散运动过程中指定每只眼睛的位置，因此必须在接收共轭速度输入的同时接收聚散速度输入。由于侧眼动物没有聚散系统，我们提出了两种可能的积分器排列模型，它们可能是从没有额前眼的低等动物的共轭方向（而非单眼）积分器发展而来的。这两种模型都解释了近反应细胞的存在，并在单侧损伤一个积分器后产生所需的双向凝视性眼震。这些模型还对单侧积分器损伤对聚散系统行为的影响做出了具体且不同的预测，从而为进一步的实验提出了建议。
