DEVELOPMENT OF VISUAL EFFICIENCY

这项研究的目的是揭示限制灵长类动物视觉表现发展的神经机制。 视觉心理物理学和理论的最新进展使得我们有可能用与分析成人视觉相同的术语来阐述有关视觉发育的问题，我们正在进行实验，以探索这些功能术语中的神经生物学发育。 该项目的实验取决于视觉效率的测量，即对比度在视觉系统中编码的保真度。 对比度阈值测量的行为在掩蔽噪声的存在或不存在下，在婴儿猕猴作为年龄的函数进行评估。 我们证实，随着动物的成熟，视觉效率随着对比敏感度的提高而提高。 为了探讨其机制，我们对新生儿外侧膝状体核（LGN）和初级视皮层（V1）的神经元进行了记录。 我们发现，LGN神经元的灵敏度和分辨率的改善程度不足以解释行为学测量的变化。 我们在V1中的记录还相当初步，但我们期望在V1中发现比在LGN水平上更大程度的成熟。 除了这些研究之外，我们还开始测量灵长类动物对视觉运动敏感性的发展。 我们计划研究大脑皮层中视觉运动处理区域的成熟，以了解婴儿视觉运动处理的成熟过程。

The goal of this research is to uncover the neuronal mechanisms that limit the development of visual performance in primates. Recent advances in visual psychophysics and theory have made it possible to formulate questions about visual development in the same terms used to analyze adult vision, and we are conducting experiments to explore the neurobiology of development in these functional terms. The experiments in this project hinge on the measurement of visual efficiency, the fidelity with which contrast is encoded in the visual system. Contrast thresholds measured behaviorally in the presence or absence of masking noise are assessed in infant macaques as a function of age. We confirmed that, as the animals mature, visual efficiency improves with contrast sensitivity. To try to establish the underlying mechanisms we recorded from neurons in lateral geniculate nucleus (LGN) and primary visual cortex (V1) in newborns. We found that the degree of improvement in sensitivity and resolution of neurons in LGN was not substantial enough to account for the behaviorally measured changes. Our recordings in V1 are as yet quite preliminary, but we expect to find a greater degree of maturation in V1 than we found at the level of the LGN. In addition to these studies, we have begun to measure the development of sensitivity to visual motion in primates. We plan to study the maturation of visual motion processing areas in the cortex to understand the maturational processes that underlie visual motion processing in infants.