Crowding is a profound loss of discriminability of visual features, when a target stimulus is surrounded by distractors. Numerous studies of human perception have characterized how crowding depends on the properties of a visual display. Yet, there is limited understanding of how and where stimulus information is lost in the visual system under crowding. Here, we show that macaque monkeys exhibit perceptual crowding for target orientation that is similar to humans. We then record from neuronal populations in monkey primary visual cortex (V1). These populations show an appreciable loss of information about target orientation in the presence of distractors, due both to divisive and additive modulation of responses to targets by distractors. Our results show that spatial contextual effects in V1 limit the discriminability of visual features and can contribute substantively to crowding.

当目标刺激物被干扰物包围时，拥挤是视觉特征辨别力的重大损失。关于人类感知的大量研究已经描述了拥挤如何取决于视觉显示器的属性。然而，对于在拥挤的情况下视觉系统中如何丢失刺激信息以及丢失丢失刺激信息的理解有限。在这里，我们显示猕猴表现出与人类相似的目标定向感知拥挤。然后，我们从猴子初级视觉皮层（V1）的神经元种群中记录。这些人群在存在干扰物的情况下显示出有关目标定向的信息的明显损失，这是由于干扰物对目标响应的分裂和累加调节。