Cardiovascular Research Center and Division of Cardiology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA.
J Neurosci. 2013 Feb 27;33(9):3834-43. doi: 10.1523/JNEUROSCI.3689-12.2013.
Nonvisual photosensation enables animals to sense light without sight. However, the cellular and molecular mechanisms of nonvisual photobehaviors are poorly understood, especially in vertebrate animals. Here, we describe the photomotor response (PMR), a robust and reproducible series of motor behaviors in zebrafish that is elicited by visual wavelengths of light but does not require the eyes, pineal gland, or other canonical deep-brain photoreceptive organs. Unlike the relatively slow effects of canonical nonvisual pathways, motor circuits are strongly and quickly (seconds) recruited during the PMR behavior. We find that the hindbrain is both necessary and sufficient to drive these behaviors. Using in vivo calcium imaging, we identify a discrete set of neurons within the hindbrain whose responses to light mirror the PMR behavior. Pharmacological inhibition of the visual cycle blocks PMR behaviors, suggesting that opsin-based photoreceptors control this behavior. These data represent the first known light-sensing circuit in the vertebrate hindbrain.
非视觉光感使动物无需视觉即可感知光。然而，非视觉光行为的细胞和分子机制还知之甚少，特别是在脊椎动物中。在这里，我们描述了光运动反应（PMR），这是一种在斑马鱼中产生的强大且可重复的一系列运动行为，它由视觉波长的光引发，但不需要眼睛、松果腺或其他典型的深部脑感光器官。与经典非视觉途径的相对缓慢的作用不同，运动回路在 PMR 行为期间被强烈且快速（秒级）募集。我们发现后脑不仅是必需的，而且足以驱动这些行为。使用体内钙成像，我们在脑内鉴定出一组离散的神经元，其对光的反应与 PMR 行为相吻合。视觉循环的药理学抑制阻断了 PMR 行为，表明视蛋白基光感受器控制着这种行为。这些数据代表了在脊椎动物后脑中首次发现的光感应回路。
