Recurrent axon collaterals of intrinsically photosensitive retinal ganglion cells
| Autor: | Dennis M. Dacey, Hannah R. Joo, Shih-Kuo Chen, Beth B. Peterson, Samer Hattar |
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| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: |
Melanopsin
Retinal Ganglion Cells genetic structures Physiology Optic Disk Giant retinal ganglion cells Biology Retinal ganglion Article Mice medicine Animals Visual Pathways Axon Feedback Physiological Retina Intrinsically photosensitive retinal ganglion cells Estrogen Antagonists Rod Opsins Inner plexiform layer Sensory Systems eye diseases Axons Mice Inbred C57BL Tamoxifen medicine.anatomical_structure Amacrine Cells Synapses Macaca sense organs Neuroscience Retinohypothalamic tract |
| Popis: | Retinal ganglion cells (RGCs), the output neurons of the retina, have axons that project via the optic nerve to diverse targets in the brain. Typically, RGC axons do not branch before exiting the retina and thus do not provide it with synaptic feedback. Although a small subset of RGCs with intraretinal axon collaterals has been previously observed in human, monkey, cat, and turtle, their function remains unknown. A small, more recently identified population of RGCs expresses the photopigment melanopsin. These intrinsically photosensitive retinal ganglion cells (ipRGCs) transmit an irradiance-coding signal to visual nuclei in the brain, contributing both to image-forming vision and to several nonimage-forming functions, including circadian photoentrainment and the pupillary light reflex. In this study, using melanopsin immunolabeling in monkey and a genetic method to sparsely label the melanopsin cells in mouse, we show that a subgroup of ipRGCs have axons that branch en route to the optic disc, forming intraretinal axon collaterals that terminate in the inner plexiform layer of the retina. The previously described collateral-bearing population identified by intracellular dye injection is anatomically indistinguishable from the collateral-bearing melanopsin cells identified here, suggesting they are a subset of the melanopsin-expressing RGC type and may therefore share its functional properties. Identification of an anatomically distinct subpopulation in mouse, monkey, and human suggests this pathway may be conserved in these and other species (turtle and cat) with intraretinal axon collaterals. We speculate that ipRGC axon collaterals constitute a likely synaptic pathway for feedback of an irradiance signal to modulate retinal light responses. |
| Databáze: | OpenAIRE |
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