Purchase this article with an account.
Arkady Lyubarsky, Jean Bennett; Light Avoidance in Mice May Be not Related to Photoreceptor-Driven Input.. Invest. Ophthalmol. Vis. Sci. 2016;57(12):2768.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
A non-visual (melanopsin-driven) pathway signaling was shown to elicit light avoidance (LA) in mice (Johnson et al., PNAS v. 107 p. 1374, 2010) but involvement of photoreceptor-driven inputs into LA had not been analyzed. We attempted to quantify photoreceptor-driven contributions into LA in order to evaluate its utility for outcome assessment in vision restoration studies.
Experiments on LA were performed with C57Bl6/J mice. Photoreceptor- and melanopsin-driven signaling was separated by their different temporal properties. Integrating times for photoreceptors are tens of milliseconds, while for melanopsin-driven signaling it is 5-10 s; and, therefore, thresholds of these pathways differ by 5-6 log units for flash stimuli, but only by ~2-3 log units for steady light. Dark-adapted C57Bl6/J mice, pupils dilated with tropicamide, were placed into an elongated black plastic box with infrared (IR) illuminated interior divided into two compartments one of which had a clear end wall. The top of the box was covered with dark red filters, and movement of mice between compartments was observed and recorded with an IR camera. The “light” compartment was the one illuminated from the clear side either with steady white light (500 and 1000 scot lux) or with 10 ms flashes of the same intensity light delivered at 1 Hz frequency. The intensity of flashes was above rod and cone thresholds by 6 and 2 log units correspondingly, and they elicited robust rod- and cone-driven responses as was confirmed by electroretinography. Total of 8 mice was tested in 10 min long trials.
Under flash illumination mice did not exhibit preference to either compartment. Under steady illumination they preferred the dark compartment (p<0.02).
(1) Stimuli producing robust rod and cone responses do not induce LA, thus no contribution of photoreceptor signaling into LA is found; (2) LA in optogenetically treated melanopsin null mice may be due to transduction of intrinsically photosensitive retinal ganglion cells; (3) utility of LA for vision assessment is questionable.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
This PDF is available to Subscribers Only