Department of Neurological Surgery, Weill Cornell Medicine, New York, NY, USA; Department of Neuroscience, Brown University, Providence, RI, USA.
Department of Neuroscience, Brown University, Providence, RI, USA.
Curr Biol. 2022 Jun 20;32(12):2654-2667.e4. doi: 10.1016/j.cub.2022.04.067. Epub 2022 May 17.
Perception in multiple sensory modalities is an active process that involves exploratory behaviors. In humans and other primates, vision results from sensory sampling guided by saccadic eye movements. Saccades are known to modulate visual perception, and a corollary discharge signal associated with saccades appears to establish a sense of visual stability. Neural recordings have shown that saccades also modulate activity widely across the brain. To investigate the neural basis of saccadic effects on perception, simultaneous recordings from multiple neurons in area V1 were made as animals performed a contrast detection task. Perceptual and neural measures were compared when the animal made real saccades that brought a stimulus into V1 receptive fields and when simulated saccades were made (identical retinal stimulation but no eye movement). When real saccades were made and low spatial frequency stimuli were presented, we observed a reduction in both perceptual sensitivity and neural activity compared with simulated saccades; conversely, with higher spatial frequency stimuli, saccades increased visual sensitivity and neural activity. The performance of neural decoders, which used the activity of the population of simultaneously recorded neurons, showed saccade effects on sensitivity that mirrored the frequency-dependent perceptual changes, suggesting that the V1 population activity could support the perceptual effects. A minority of V1 neurons had significant choice probabilities, and the saccades decreased both average choice probability and pairwise noise correlations. Taken together, the findings suggest that a signal related to saccadic eye movements alters V1 spiking to increase the independence of spiking neurons and bias the system toward processing higher spatial frequencies, presumably to enhance object recognition. The effects of saccades on visual perception and noise correlations appear to parallel effects observed in other sensory modalities, suggesting a general principle of active sensory processing.
多模态感知是一个主动的过程，涉及探索性行为。在人类和其他灵长类动物中，视觉是由眼球跳动引导的感觉采样产生的。眼球跳动被认为可以调节视觉感知，并且与眼球跳动相关的副放电信号似乎建立了视觉稳定性的感觉。神经记录表明，眼球跳动也广泛调节大脑的活动。为了研究眼球跳动对感知的神经基础，当动物执行对比度检测任务时，在 V1 区域同时记录多个神经元的活动。当动物进行真正的眼球跳动，将刺激带入 V1 感受野，以及进行模拟眼球跳动（相同的视网膜刺激但没有眼球运动）时，比较感知和神经测量。当进行真正的眼球跳动并呈现低空间频率刺激时，与模拟眼球跳动相比，我们观察到感知敏感性和神经活动都降低；相反，高空间频率刺激时，眼球跳动增加了视觉敏感性和神经活动。使用同时记录的神经元群体活动的神经解码器的性能表明，敏感性上的眼球跳动效应与频率相关的感知变化相匹配，这表明 V1 群体活动可以支持感知效应。少数 V1 神经元具有显著的选择概率，而眼球跳动降低了平均选择概率和成对噪声相关性。总的来说，这些发现表明与眼球运动相关的信号改变了 V1 的尖峰发放，增加了尖峰神经元的独立性，并使系统偏向处理更高空间频率，可能是为了增强物体识别。眼球跳动对视觉感知和噪声相关性的影响似乎与在其他感觉模态中观察到的影响平行，这表明主动感觉处理的一般原则。
