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Updated: Aug 11, 2026

An Isolated Retinal Preparation to Record Light Response from Genetically Labeled Retinal Ganglion Cells
Published on: January 26, 2011
Photoreceptor adaptation in intrinsically photosensitive retinal ganglion cells
Kwoon Y Wong1, Felice A Dunn, David M Berson
1Department of Neuroscience, Brown University, Providence, Rhode Island 02912, USA. kwoon_wong@brown.edu
Abstract:
A rare type of mammalian retinal ganglion cell (RGC) expresses the photopigment melanopsin and is a photoreceptor. These intrinsically photosensitive RGCs (ipRGCs) drive circadian-clock resetting, pupillary constriction, and other non-image-forming photic responses. Both the light responses of ipRGCs and the behaviors they drive are remarkably sustained, raising the possibility that, unlike rods and cones, ipRGCs do not adjust their sensitivity according to lighting conditions ("adaptation"). We found, to the contrary, that ipRGC sensitivity is plastic, strongly influenced by lighting history. When exposed to a constant, bright background, the background-evoked response decayed, and responses to superimposed flashes grew in amplitude, indicating light adaptation. After extinction of a light-adapting background, sensitivity recovered progressively in darkness, indicating dark adaptation. Because these adjustments in sensitivity persisted when synapses were blocked, they constitute "photoreceptor adaptation" rather than "network adaptation." Implications for the mechanisms generating various non-image-forming visual responses are discussed.
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