Function of fixation instability during natural viewing

描述(申请人提供)：在正常观看期间，视觉场景在视网膜上的投影永远不会静止。即使在短暂的视觉注视期间，小的眼球运动与头部和身体的运动相结合，也能保持视网膜图像的运动。注视不稳定可能是视觉场景信息在大脑中获得和呈现的一个重要组成部分。通过影响神经元反应的时间结构，它可能有助于视觉信息的编码，而不仅仅是刷新神经元反应以防止不变刺激的褪色。模拟眼球运动活动中的神经元反应的模拟研究表明，这种情况可能发生的具体机制。这一建议结合了视觉心理物理学和神经元模型，以检验注视眼球运动对识别与短暂的视觉注视时间相当的刺激的影响。人体的心理物理实验将比较有无视网膜图像运动时的识别性能，并将眼睛运动的精细结构与视觉识别联系起来。实验将既依赖于传统的视网膜稳定技术，也依赖于一种新的凝视显示系统，该系统将允许在眼跳后的注视期间选择性地消除眼球运动。神经元模型将模拟视网膜、LGN和V1中神经元的反应。对于每个实验试验，一个模拟将复制受试者进行的眼球运动序列中的神经元活动。受试者的表现和神经元放电传递的刺激信息将在逐个试验的基础上进行比较。许多视觉障碍表现为异常的凝视眼球运动。除了促进我们对视觉感知的基本理解外，对注视不稳定的功能暗示的理解可能会导致通常与这种情况相关的视觉损伤的治疗。

DESCRIPTION (provided by applicant): During normal viewing, the projection of the visual scene on the retina is never stationary. Even during the brief periods of visual fixation, small eye movements combine with movements of the head and the body to keep the retinal image in motion. Fixational instability may be an important component of how information about a visual scene is acquired and represented in the brain. By affecting the temporal structure of neuronal responses, it may contribute to the encoding of visual information in a way that goes beyond simply refreshing neuronal responses to prevent the fading of unchanging stimuli. Modeling studies that simulated neuronal responses during oculomotor activity suggest specific mechanisms by which this may occur. This proposal combines visual psychophysics and neuronal modeling to examine the influence of fixational eye movements on the identification of stimuli presented for periods comparable to the brief durations of visual fixation. Psychophysical experiments with human subjects will compare identification performances in the presence and absence of retinal image motion and correlate the fine structure of eye movements to visual identification. Experiments will rely both on a traditional technique of retinal stabilization as well as on a new system of gaze-contingent display that will allow selective elimination of eye movements during the periods of fixation following saccades. Neuronal models will simulate the responses of neurons in the retina, LGN and V1. For every experimental trial, a simulation will replicate neuronal activity during the sequence of eye movements performed by the subject. Subject performance and the information about the stimulus transmitted by neuronal firing will be compared on a trial-by-trial basis. A number of visual disorders manifest abnormal fixational eye movements. In addition to advance our basic understanding of visual perception, a comprehension of the functional implications of fixational instability may lead to treatment of the visual impairments commonly associated with such conditions.