NEUROPHYSIOLOGY OF VISION

这个子项目是利用资源的许多研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目的总成本可能 代表子项目使用的中心基础设施的估计数量， NCRR赠款不直接向子项目或子项目工作人员提供资金。 微扫视可以提高人类观察者的对比度检测阈值，并调节猴视皮层神经元的活动。 微扫视是否会提高猴子观察者的对比度检测阈值尚不清楚，这取决于神经生理学实验的解释。 为了回答这个问题，我们训练两只猴子执行2AFC对比度检测任务。 在刺激呈现期间发生微扫视的试验中，表现更差。 影响的程度是适度的（阈值变化为0.2 log单位）和颜色特异性：无色敏感性受损，但红绿敏感性没有。 为了探索这种效应的神经基础，我们记录了单个V1神经元对白色噪声刺激的反应。 微扫视产生的尖峰活动的抑制，随后兴奋性反弹，这是类似的L-M锥对手和L+M非对手V1神经元。 我们的结论是，猴子的微扫视增加亮度对比度检测阈值和调制的尖峰活动的V1神经元，但亮度特异性的行为抑制可能是下游的V1。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Microsaccades can elevate contrast detection thresholds of human observers and modulate the activity of neurons in monkey visual cortex. Whether microsaccades elevate contrast detection thresholds in monkey observers is not known and bears on the interpretation of neurophysiological experiments. To answer this question, we trained two monkeys to perform a 2AFC contrast detection task. Performance was worse on trials in which a microsaccade occurred during the stimulus presentation. The magnitude of the effect was modest (threshold changes of 0.2 log units) and color specific: achromatic sensitivity was impaired but red-green sensitivity was not. To explore the neural basis of this effect, we recorded the responses of individual V1 neurons to a white noise stimulus. Microsaccades produced a suppression of spiking activity followed by a excitatory rebound that was similar for L-M cone-opponent and L+M non-opponent V1 neurons. We conclude that microsaccades in the monkey increase luminance contrast detection thresholds and modulate the spiking activity of V1 neurons, but the luminance-specificity of the behavioral suppression is likely implemented downstream of V1.