Development of Visual Stability in Human Infants

这个研究项目的目标是确定在什么年龄， 幼儿是通过什么样的潜在机制来感知视觉的 世界是稳定的，尽管眼睛，头部和身体的运动。 成年人感知的视觉世界是稳定的， 主要通过反射性眼球运动触发的运动 通过视觉和前庭刺激。 这些眼球运动 为了减少或消除视网膜图像的那些移动， 都是由自发的运动创造的。 前庭眼 反射（VOR），由头部的旋转或平移触发， 眼睛向与头部相反的方向转动 运动 视动反射（OKR）在视觉上移动眼睛。 视网膜图像运动的方向。 这些反射是 辅以视网膜图像的细粒度分析 位于当前注视方向附近的速度， 转换成用于平滑追踪的眼动信号 系统 在一个典型的视觉环境中， 不同的距离，观察者必须选择一个深度平面 固定和抑制这些视网膜图像运动所产生的 近距离和远距离的物体。 当视觉场景 移动，无论是因为物体的移动还是物体的移动， 观察者，三个眼科系统- VOR，OKR和平滑 追求-被激活的协调一致，以稳定出席 尽管其他视网膜图像的运动。 这些 实验将呈现2至6个月大的人类婴儿， 当他们被关在马厩里时， 头部/身体位置或固定视觉显示器， 头部/身体横向移动。 前一个条件刺激 OKR和平滑追踪系统，而后者条件 刺激所有三个系统来揭示VOR的作用。 在 问题是婴儿如何有效地保持目标， 注意力稳定在视网膜上， 视觉环境和/或头部/身体的运动。 基于 早期的工作表明，光滑的追求不会出现，直到2 4个月大时，深度知觉才出现， Aslin预测，如果平滑追踪系统是 关键因素，那么有效的稳定应该出现在2 月龄。 然而，如果物体在深度上的分离是 关键因素，那么有效的稳定不应该 直到4个月大。 这些结果来自正常婴儿 将提供一个基线， 三种眼科系统， 成年人对稳定视觉世界的感知

The goal of this research project is to determine at what age and with what underlying mechanism young infants perceive the visual world as stable despite movements of the eyes, head, and body. Adults perceive the visual world as stable despite self-produced movements primarily by means of reflexive eye movements triggered by visual and vestibular stimulation. These eye movements serve to reduce or eliminate those movements of the retinal image that are created by self-produced movements. The vestibulo-ocular reflex (VOR), triggered by rotations or translations of the head, counter-rolls the eyes in the direction opposite to head movement. The optokinetic reflex (OKR) moves the eyes in the direction of retinal image movement. These reflexes are supplemented by a fine-grained analysis of retinal image velocities located near the current direction of gaze and converted into eye movement signals for the smooth pursuit system. In a typical visual environment with objects at many different distances, the observer must select a depth-plane for fixation and suppress those retinal image motions created by objects at nearer and farther distances. When the visual scene moves, either because of object movement or movement of the observer, the three oculomotor systems -- VOR, OKR, and smooth pursuit -- are activated in concert to stabilize the attended object despite the movements of other retinal images. These experiments will present 2- to 6-month-old human infants either with moving visual displays while they are held in a stable head/body position or with stationary visual displays while their head/body is moved laterally. The former condition stimulates the OKR and smooth pursuit systems, while the latter condition stimulates all three systems to reveal the role of the VOR. At issue is how effectively infants are able to keep the object of attention stabilized on the retina despite movements of the visual surround and/or movements of the head/body. Based on earlier work showing that smooth pursuit does not emerge until 2 months of age and depth perception does not emerge until 4 months of age, Aslin predicts that if the smooth pursuit system is the critical factor, then effective stabilization should emerge at 2 months of age. However, if segregation of objects in depth is the critical factor, then effective stabilization should not emerge until 4 months of age. These results from normal infants will provide a baseline for understanding the development of three oculomotor systems that are known to be essential for adults' perception of a stable visual world.