Environmental light intensity (irradiance) is a powerful regulator of behavior. A stable neuronal representation of light intensity is grounded in a specialized retinal output channel, found in humans and other mammals, and arising from intrinsically photosensitive retinal ganglion cells (ipRGCs). These are a rare class of retinal ganglion cells with autonomous sensitivity to light by virtue of their expression of the photopigment melanopsin. Light intensity signals from ipRGCs, are conveyed to a myriad of brain regions and affect among other functions, circadian clock photoentrainment, pupil constriction, neuroendocrine rhythms regulation, sleep, learning, and mood.
ipRGCs are a diverse set of neurons, and their influence on visual behavior is widespread and complex. Much is yet to be revealed about this system at the molecular, cellular, circuit and behavioral level. For example, ipRGCs are themselves a heterogeneous population of neurons, with defined functional and anatomical hallmarks – what is the contribution of these distinct subtypes to vision, and what physiological advantage does this diversity provide? Similarly, while some ipRGCs contribute to image formation through their projection to the dorsal lateral geniculate nucleus, other ipRGCs project to diverse brain regions mediating non-canonical effects of light on physiology and behavior – how does the visual information conveyed by ipRGCs feed into those distinct visual circuits, and how does this ultimately modulate the behavior of animals, and indeed humans? Lastly, in addition to transmitting light intensity signals to the brain, ipRGCs also transmit intensity-dependent input back to the retina, via both synaptic and electrical connections. We still do not have a clear grasp of the importance of this feedback signal, but evidence suggests it could have critical roles both in retinal development and in modulating the behavior of ‘conventional’ retinal circuits.
This Research Topic aims to provide a comprehensive overview of the most recent advances in ipRGC biology, encompassing the anatomy and physiology of ipRGCs, their roles in mediating the function of the retina and higher brain centers, and modulating the behavior of animals and humans. This Research Topic welcomes original research papers, reviews, mini-reviews, perspectives, and opinion articles covering but are not limited to the following topics:
1. ipRGCs’ contribution to image formation and their role in mediating non-canonical effects of light on physiology and behavior
2. ipRGCs effects on the function of other retinal neurons
3. ipRGCs development
4. Intra- and inter-specific variation of ipRGCs
Environmental light intensity (irradiance) is a powerful regulator of behavior. A stable neuronal representation of light intensity is grounded in a specialized retinal output channel, found in humans and other mammals, and arising from intrinsically photosensitive retinal ganglion cells (ipRGCs). These are a rare class of retinal ganglion cells with autonomous sensitivity to light by virtue of their expression of the photopigment melanopsin. Light intensity signals from ipRGCs, are conveyed to a myriad of brain regions and affect among other functions, circadian clock photoentrainment, pupil constriction, neuroendocrine rhythms regulation, sleep, learning, and mood.
ipRGCs are a diverse set of neurons, and their influence on visual behavior is widespread and complex. Much is yet to be revealed about this system at the molecular, cellular, circuit and behavioral level. For example, ipRGCs are themselves a heterogeneous population of neurons, with defined functional and anatomical hallmarks – what is the contribution of these distinct subtypes to vision, and what physiological advantage does this diversity provide? Similarly, while some ipRGCs contribute to image formation through their projection to the dorsal lateral geniculate nucleus, other ipRGCs project to diverse brain regions mediating non-canonical effects of light on physiology and behavior – how does the visual information conveyed by ipRGCs feed into those distinct visual circuits, and how does this ultimately modulate the behavior of animals, and indeed humans? Lastly, in addition to transmitting light intensity signals to the brain, ipRGCs also transmit intensity-dependent input back to the retina, via both synaptic and electrical connections. We still do not have a clear grasp of the importance of this feedback signal, but evidence suggests it could have critical roles both in retinal development and in modulating the behavior of ‘conventional’ retinal circuits.
This Research Topic aims to provide a comprehensive overview of the most recent advances in ipRGC biology, encompassing the anatomy and physiology of ipRGCs, their roles in mediating the function of the retina and higher brain centers, and modulating the behavior of animals and humans. This Research Topic welcomes original research papers, reviews, mini-reviews, perspectives, and opinion articles covering but are not limited to the following topics:
1. ipRGCs’ contribution to image formation and their role in mediating non-canonical effects of light on physiology and behavior
2. ipRGCs effects on the function of other retinal neurons
3. ipRGCs development
4. Intra- and inter-specific variation of ipRGCs