Chan W W P, Galiana H L
Dept. Biomedical Engineering, McGill University, 3775 University St., Rm 308, Montreal, Quebec H3A 2B4, Canada.
J Neurophysiol. 2005 Jun;93(6):3709-17. doi: 10.1152/jn.00814.2004. Epub 2005 Feb 9.
The oculomotor integrator is usually defined by the characteristics of decay in gaze after saccades to flashed targets or after spontaneous gaze shifts in the dark. This property is then presumed fixed and accessed by other ocular reflexes, such as the vestibuloocular reflex (VOR) or pursuit, to shape motoneural signals. An alternate view of this integrator proposes that it relies on a distributed network, which should change its properties with sensory-motor context. Here we demonstrate in 10 normal subjects that the function of integration can vary in an individual with the imposed test. The value of the time constant for the decay of gaze holding in the dark can be significantly different from the effective integration time constant estimated from VOR responses. Hence analytical tools for the study of dynamics in ocular reflexes must allow for nonideal and labile integrator function. The mechanisms underlying such labile integration remain to be explored and may be different in various ocular reflexes (e.g., visual versus vestibular).
动眼整合器通常由扫视至闪光目标后或在黑暗中自发眼动后注视的衰减特性来定义。然后假定该特性是固定的，并可被其他眼反射（如前庭眼反射（VOR）或追踪）利用，以塑造运动神经信号。关于这个整合器的另一种观点认为，它依赖于一个分布式网络，其特性应随感觉运动背景而改变。在此，我们在10名正常受试者中证明，整合功能会因施加的测试而在个体中有所不同。黑暗中注视保持衰减的时间常数的值可能与根据VOR反应估计的有效整合时间常数有显著差异。因此，用于研究眼反射动力学的分析工具必须考虑到非理想和不稳定的整合器功能。这种不稳定整合背后的机制仍有待探索，并且在各种眼反射中（例如视觉与前庭）可能有所不同。
