Department of Psychology, University of Pennsylvania, Philadelphia, PA 19104.
Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104.
Proc Natl Acad Sci U S A. 2017 Nov 14;114(46):12291-12296. doi: 10.1073/pnas.1711522114. Epub 2017 Oct 31.
The photopigment melanopsin supports reflexive visual functions in people, such as pupil constriction and circadian photoentrainment. What contribution melanopsin makes to conscious visual perception is less studied. We devised a stimulus that targeted melanopsin separately from the cones using pulsed (3-s) spectral modulations around a photopic background. Pupillometry confirmed that the melanopsin stimulus evokes a response different from that produced by cone stimulation. In each of four subjects, a functional MRI response in area V1 was found. This response scaled with melanopic contrast and was not easily explained by imprecision in the silencing of the cones. Twenty additional subjects then observed melanopsin pulses and provided a structured rating of the perceptual experience. Melanopsin stimulation was described as an unpleasant, blurry, minimal brightening that quickly faded. We conclude that isolated stimulation of melanopsin is likely associated with a response within the cortical visual pathway and with an evoked conscious percept.
视蛋白色素 melanopsin 支持人体的反射性视觉功能，例如瞳孔收缩和昼夜节律的光适应。视蛋白色素对意识视觉感知的贡献研究较少。我们设计了一种刺激物，使用围绕明视觉背景的脉冲（3 秒）光谱调制来将 melanopsin 与视锥细胞分开靶向。瞳孔测量法证实，melanopsin 刺激会引起与视锥细胞刺激产生的反应不同的反应。在四个受试者中的每一个中，都发现了 V1 区的功能磁共振成像响应。该响应与视蛋白对比度成比例，并且不能轻易地通过视锥细胞的抑制不精确来解释。然后，另外 20 名受试者观察了 melanopsin 脉冲，并对感知体验进行了结构化评分。Melanopsin 刺激被描述为不愉快、模糊、轻微的增亮，很快就消失了。我们得出结论，单独刺激 melanopsin 可能与皮质视觉通路内的反应以及诱发的意识知觉有关。
