平滑追随眼动的神经机制综述

Review on the Neurological Mechanisms of Smooth Pursuit Eye Movement

平滑追随眼动作为视觉引导的眼动行为之一,是指为保障对运动目标的精细觉察,眼睛追随慢速运动的目标以使其处于中央凹位置时眼球的运动情况。本文简要归纳介绍了平滑追随眼动的实验范式、测量指标和影响因素,在此基础上重点详述了平滑追随眼动的皮质—脑桥—小脑神经通路,其中皮质区的额眼区、辅眼区、颞中区、内侧上颞区及侧顶区在平滑追随眼动的产生中具有不同作用;而脑桥核和脑桥被盖网状核作为中继站负责将来自顶枕区和额叶区信号传递到小脑中参与眼动的区域;小脑的绒球和副绒球及蚓体负责处理平滑追随的眼动信号,并协调前庭神经反射。对平滑追随眼动的理解不仅可以帮助我们区分眼动的正常与否,发挥其临床诊断和药理学评估的作用,而且有助于确定患者大脑器质性病变或损伤的程度,同时为进一步的实验认知研究和验证提供理论基础。

Smooth pursuit eye movements （SPEMs） , as one form of visually guided eye movement, are used to stabilize the image of a slowly moving object of interest on the fovea in order to facilitate the high-acuity scrutiny of a moving object. This article briefly introduces the experimental paradigms and measurement indices of SPEMs used in different studies and the influential factors of smooth pursuit eye movements. Specifically, we focused on the cerebro-ponto-cerebellar pathway that is served as the substrate of SPEMs,which suggested that some parts of frontal （i. e. FEF and SEF）and parietooccipital（ i. e. MT, MST and LIP） areas have distinctive roles in generating smooth pursuit eye movements. While the dorsal pontine nuclei（ PN） and the nucleus reticularis tegmenti pontis （NRTP）play the role as intermediary stations to receive the efferent originating from the parietooccipital and frontal areas that contribute to smooth pursuit and project them to several eerebellars regions involved in eye movements. The cerebellum uses the flocculus-parafloeculus complex and the posterior vermis to process signals relevant to smooth pursuit and represent the pursuit related information that is mainly used for the coordination of vestibular reflexes. To understand the SPEMs will not only help us differentiate the abnormal eye movements from normal ones and contribute to the clinical diagnosis, prognostic evaluation and pharma- cological evaluation, but also ascertain the organic disease and the extent of the brain impairment. Moreover, it will provide us the theoretical foundation for further experimental validity and study from the perspective of experimental cognition.