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我们有可能用分析成人视力的相同术语来阐述关于视觉发育的问题，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。这个项目中的实验依赖于视觉效率的测量，即视觉系统中对比度编码的保真度。在存在或不存在掩蔽噪声的情况下，对婴儿猕猴的对比阈值进行了评估，作为年龄的函数。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。为了试图建立潜在的机制，我们记录了新生儿外侧膝状体核(LGN)和初级视皮层(V1)的神经元。我们发现，LGN神经元的敏感度和分辨率的改善程度不足以解释行为测量的变化。到目前为止，我们在V1中的录音还很初步，但我们预计V1中的成熟程度将比我们在LGN水平上发现的更高。除了这些研究，我们已经开始测量灵长类动物对视觉运动的敏感度的发展。我们计划研究大脑皮质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.