【NTU MIC講座：視網膜內特殊感光視神經調控光適應】
Neuronal connection of intrinsically photosensitive retinal ganglion cells: how light influence physiological functions
時間：2/17 (五) 12：30
地點：國立臺灣大學校總區生物科技館 R101
講師：陳示國教授
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摘要：Retinal ganglion cells (RGCs) in the retina receive input from classical photoreceptor rod and cone through bipolar cells and many lateral processing from amacrine cell. For image forming function, classic photoreceptor rods and cones are primary photon detector located at the outer retina. However, recent studies showed that a small population of melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs) located at the inner retina is essential for many non-image forming visual functions. There are many subtypes of ipRGCs which provide environmental luminance signal for circadian photoentrainmnet, pupillary light reflex. Furthermore, ipRGCs could also influence the physiological functions of upstream order of retinal neuron such as dopaminergic amacrine cell and even the retinal development through intra-retinal axon collaterals. Therefore, ipRGC could conveying luminance signal from the inner retina to outer retina to control light adaptation and simultaneously to the hypothalamus for other non-image forming function such as circadian clock modulation. We also construct the innervation pattern of ipRGC to the SCN, the brain nucleus controls circadian clock. Unlike regular sensory neurons which usually innervate opposite side of the brain, a single ipRGC can project bi-lateral innervation to both left and right side of the brain. This innervation pattern could provide information input to SCN for potential better synchronization of the biological clock. Together, our studies showed that the atypical photoreceptor in the retina can modulate many of our physiological function from vision to clock.
