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。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 微眼跳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。微眼跳是否会提高猴子观察者的对比度检测阈值尚不清楚，这与神经生理学实验的解释有关。为了回答这个问题，我们训练了两只猴子执行2AFC对比度检测任务。在刺激呈现过程中出现微跳的试验中，表现更差。影响的程度不大(阈值变化为0.2个对数单位)和特定的颜色：非彩色敏感度受损，但红绿敏感度不受影响。为了探索这种效应的神经基础，我们记录了单个V1神经元对白噪声刺激的反应。微扫视抑制放电活动，随后产生兴奋性反弹，这与L-M视锥对抗性神经元和L+M非对抗性V1神经元的作用相似。我们得出结论，猴子的微扫视提高了亮度对比度检测阈值，并调节了V1神经元的放电活动，但这种行为抑制的亮度特异性可能是在V1的下游实现的。

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.