Graduate Center for Vision Research, SUNY College of Optometry, New York, NY, 10036, USA.
Graduate Center for Vision Research, SUNY College of Optometry, New York, NY, 10036, USA; School of Electrical Engineering, Iran University of Science and Technology, Narmak, Tehran, Iran.
Neuron. 2014 Apr 2;82(1):224-34. doi: 10.1016/j.neuron.2014.02.020.
Visual information is mediated by two major thalamic pathways that signal light decrements (OFF) and increments (ON) in visual scenes, the OFF pathway being faster than the ON. Here, we demonstrate that this OFF temporal advantage is transferred to visual cortex and has a correlate in human perception. OFF-dominated cortical neurons in cats responded ∼3 ms faster to visual stimuli than ON-dominated cortical neurons, and dark-mediated suppression in ON-dominated neurons peaked ∼14 ms faster than light-mediated suppression in OFF-dominated neurons. Consistent with the neuronal differences, human observers were 6-14 ms faster at detecting darks than lights and better at discriminating dark than light flickers. Neuronal and perceptual differences both vanished if backgrounds were biased toward darks. Our results suggest that the cortical OFF pathway is faster than the ON pathway at increasing and suppressing visual responses, and these differences have parallels in the human visual perception of lights and darks.
视觉信息由两条主要的丘脑通路介导，它们分别对视觉场景中的光递减（OFF）和递增（ON）信号进行传递，其中 OFF 通路比 ON 通路更快。在这里，我们证明了这种 OFF 时间优势会传递到视觉皮层，并在人类感知中具有相关性。猫的 OFF 主导皮层神经元对视觉刺激的反应速度比 ON 主导皮层神经元快约 3 毫秒，而在 ON 主导神经元中，暗介导的抑制比在 OFF 主导神经元中光介导的抑制快约 14 毫秒。与神经元差异一致，人类观察者检测暗的速度比检测光的速度快 6-14 毫秒，并且更好地区分暗闪烁和光闪烁。如果背景偏向于暗，那么神经元和感知差异都会消失。我们的结果表明，在增加和抑制视觉反应方面，皮层 OFF 通路比 ON 通路更快，这些差异在人类对光和暗的视觉感知中具有相似之处。
