title: A neuronal circuit for colour vision based on rod-cone opponency.
abstract: In bright light, cone-photoreceptors are active and colour vision derives from a comparison of signals in cones with different visual pigments. This comparison begins in the retina, where certain retinal ganglion cells have 'colour-opponent' visual responses-excited by light of one colour and suppressed by another colour. In dim light, rod-photoreceptors are active, but colour vision is impossible because they all use the same visual pigment. Instead, the rod signals are thought to splice into retinal circuits at various points, in synergy with the cone signals. Here we report a new circuit for colour vision that challenges these expectations. A genetically identified type of mouse retinal ganglion cell called JAMB (J-RGC), was found to have colour-opponent responses, OFF to ultraviolet (UV) light and ON to green light. Although the mouse retina contains a green-sensitive cone, the ON response instead originates in rods. Rods and cones both contribute to the response over several decades of light intensity. Remarkably, the rod signal in this circuit is antagonistic to that from cones. For rodents, this UV-green channel may play a role in social communication, as suggested by spectral measurements from the environment. In the human retina, all of the components for this circuit exist as well, and its function can explain certain experiences of colour in dim lights, such as a 'blue shift' in twilight. The discovery of this genetically defined pathway will enable new targeted studies of colour processing in the brain.
authors.affiliation: Harvard University, 52 Oxford Street, Cambridge, Massachusetts 02138, USA.
authors.forename: Maximilian
authors.initials: M
authors.lastname: Joesch
authors.affiliation: Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125, USA.
authors.forename: Markus
authors.initials: M
authors.lastname: Meister
mesh_terms: D000818:Animals; D003116:Color; D003118:Color Perception / Q000502:physiology* / Q000528:radiation effects; D055253:Color Vision / Q000502:physiology* / Q000528:radiation effects; D003624:Darkness; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D008959:Models, Neurological; D009434:Neural Pathways / Q000502:physiology* / Q000528:radiation effects; D017949:Retinal Cone Photoreceptor Cells / Q000378:metabolism* / Q000528:radiation effects; D012165:Retinal Ganglion Cells / Q000378:metabolism / Q000528:radiation effects; D017948:Retinal Rod Photoreceptor Cells / Q000378:metabolism* / Q000528:radiation effects; D013569:Synapses / Q000378:metabolism / Q000528:radiation effects; D013731:Territoriality; D014466:Ultraviolet Rays