DEVELOPMENT OF HYPERACUITY IN HUMAN INFANTS

成人视觉系统的复杂性和能力是 非常了不起 也许同样令人印象深刻的是， 这些能力是在第一次 几年的生活。 本提案中描述的实验是 这是对以前研究的一个重要方面的延伸， 大脑皮层视觉处理的发展。 具体来说，方向调整的成熟将是 在人类婴儿中使用电生理学和 心理物理技术 四种不同的视觉诱发电位（VEP）实验， 三项心理物理学研究使用了偏好性注视（PL）， 将进行视动性眼球震颤（OKN）。 戴面具， 适应、交叉定向抑制和定向 调整双目相互作用将被用来检查 方向选择性的发展。 通过比较 定向选择性的发育时间过程与 游标敏锐度，应该可以确定是否 游标敏锐度的发展（也被认为代表了 皮质过程）取决于，或以某种方式与， 方向调整的发展。 线之间的关系 检测阈值和游标敏锐度也将在 婴儿。 这些实验不仅与我们的 了解发展，也可以提供证据， 关于游标敏锐度的潜在机制。 的 定向研究也可以提供关于 高级皮质过程的发展， 运动分析。 由于正常发育很容易改变 在快速变化的时期，理解正常的视觉 发展对理解各种 视觉异常（例如，弱视和斜视）。

The complexities and capabilities of the adult visual system are quite remarkable. Perhaps equally impressive is the process by which these abilities are developed and refined during the first few years of life. The experiments described in this proposal are an extension of previous research on one critical aspect of this development, the development of cortical processing of vision. Specifically, the maturation of orientation tuning will be investigated in human infants using both electrophysiological and psychophysical techniques. Four different visually evoked potential (VEP) experiments and three psychophysical studies using preferential looking (PL) or optokinetic nystagmus (OKN) will be conducted. Masking, adaptation, cross orientational inhibition, and the orientation tuning of binocular interactions will be used to examine the development of orientation selectivity. By comparing the developmental time course of orientation selectivity with that of vernier acuity, it should be possible to determine if the development of vernier acuity (also believed to represent a cortical process) depends on, or is in some way linked to, the development of orientation tuning. The relationship between line detection thresholds and vernier acuity will also be explored in infants. These experiments have relevance not only to our understanding of development, but also may provide evidence regarding the mechanisms underlying vernier acuity. The orientation studies may also provide indirect evidence about the development of higher order cortical processes involved in the analysis of motion. Since normal development is easily altered during periods of rapid change, understanding normal visual development have important implications for understanding various anomalies of vision (e.g., amblyopia and strabismus).