Pack C, Grossberg S, Mingolla E
Harvard Medical School, USA.
J Cogn Neurosci. 2001 Jan 1;13(1):102-20. doi: 10.1162/089892901564207.
Smooth pursuit eye movements (SPEMs) are eye rotations that are used to maintain fixation on a moving target. Such rotations complicate the interpretation of the retinal image, because they nullify the retinal motion of the target, while generating retinal motion of stationary objects in the background. This poses a problem for the oculomotor system, which must track the stabilized target image while suppressing the optokinetic reflex, which would move the eye in the direction of the retinal background motion (opposite to the direction in which the target is moving). Similarly, the perceptual system must estimate the actual direction and speed of moving objects in spite of the confounding effects of the eye rotation. This paper proposes a neural model to account for the ability of primates to accomplish these tasks. The model simulates the neurophysiological properties of cell types found in the superior temporal sulcus of the macaque monkey, specifically the medial superior temporal (MST) region. These cells process signals related to target motion, background motion, and receive an efference copy of eye velocity during pursuit movements. The model focuses on the interactions between cells in the ventral and dorsal subdivisions of MST, which are hypothesized to process target velocity and background motion, respectively. The model explains how these signals can be combined to explain behavioral data about pursuit maintenance and perceptual data from human studies, including the Aubert--Fleischl phenomenon and the Filehne Illusion, thereby clarifying the functional significance of neurophysiological data about these MST cell properties. It is suggested that the connectivity used in the model may represent a general strategy used by the brain in analyzing the visual world.
平稳跟踪眼球运动（SPEMs）是用于保持对移动目标的注视的眼球转动。这种转动使视网膜图像的解释变得复杂，因为它们消除了目标的视网膜运动，同时在背景中产生了静止物体的视网膜运动。这给动眼系统带来了一个问题，动眼系统必须跟踪稳定的目标图像，同时抑制视动反射，视动反射会使眼睛朝着视网膜背景运动的方向移动（与目标移动的方向相反）。同样，感知系统必须估计移动物体的实际方向和速度，尽管存在眼球转动的混淆效应。本文提出了一个神经模型来解释灵长类动物完成这些任务的能力。该模型模拟了猕猴颞上沟中发现的细胞类型的神经生理特性，特别是颞上内侧（MST）区域。这些细胞处理与目标运动、背景运动相关的信号，并在跟踪运动期间接收眼球速度的传出副本。该模型关注MST腹侧和背侧细分区域中细胞之间的相互作用，据推测，它们分别处理目标速度和背景运动。该模型解释了这些信号如何组合起来解释关于跟踪维持的行为数据和来自人类研究的感知数据，包括奥伯特 - 弗莱施尔现象和菲勒内错觉，从而阐明了关于这些MST细胞特性的神经生理数据的功能意义。有人认为，模型中使用的连接性可能代表了大脑在分析视觉世界时使用的一种通用策略。
