Retinal and brain circuits underlying the effects of light on circadian rhythms, learning and mood
Light exerts powerful biological effects beyond image vision such as controlling our internal biological clocks and our sleep wake cycles. Recently, mood and learning were also found to be directly regulated by light. We discovered that the source of photic information affecting circadian rhythms, sleep, mood and cognitive functions is well established, viz. intrinsically photosensitive retinal ganglion cells (ipRGCs), however, the central mediators of such effects are still incompletely known. We recently revealed that the direct effects of light on learning and mood utilize distinct ipRGC output streams. ipRGCs that project to the suprachiasmatic nucleus (SCN) mediate the effects of light on learning, independently of the SCN’s pacemaker function. Mood regulation by light, on the other hand, requires an SCN-independent pathway linking ipRGCs to a previously unrecognized thalamic region, termed perihabenular nucleus (PHb). In this talk, I will present our most recent evidence delineating the retinal circuits that allow ipRGCs to influence such wide range of innate and crucial behaviors.
Dr. Samer Hatter is a Senior Investigator at NIMH.
This event is open to the public.