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Jan J Kremers, Anneka Joachimsthaler; The dynamics of rod and cone driven ERG adaptation using the silent substitution stimulation technique. Invest. Ophthalmol. Vis. Sci. 2018;59(9):4441. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
We recently used the physiologically normal Opn1lwLIAIS (LIAIS) mouse, in which the native M-cone pigment is replaced by a human L-cone pigment, to selectively stimulate the rods or the cones with the silent substitution stimulation technique and to determine the luminance conditions to optimally separate rod and cone driven ERGs. We here use these conditions to study separately their adaptation dynamics.
ERG recordings were performed on anesthetized LIAIS mice. Stimuli for ERG recordings: sinusoidal modulation rod or cone isolation using double silent substitution (S-cones were always silenced). Procedure: After 10 minutes adaptation to 0.4 cd/m2 ERGs were measured, followed by 11 min adaptation to 8.8 cd/m2 background and recordings directly after the change in background and every 2nd minute. Finally during adaptation to 0.4 cd/m2 for 32 minutes ERG responses were recorded directly after the change in background and every 2nd minute. This protocol was repeated with rod isolating stimuli (8 Hz; 75 % rod contrast), cone isolating stimuli (12 Hz; 55% cone contrast) and white light (8 Hz and 12 Hz; 100% Michelson contrast).
At 8.8 cd/m2 responses directly displayed photopic response properties without subsequent response changes neither in cone nor white light responses. Rod driven responses were very small. 12 Hz white light responses had similar characteristics as the cone driven response. After the return to 0.4 cd/m2 both rod driven and white light responses increased over a time course of about 20 minutes. The 8 Hz white light responses were similar to the rod driven responses. Cone driven responses were very small. Response phases changed directly after a change in background without further alterations.
Rod and cone driven signal pathways display different adaptation characteristics: Adaptation of cone driven responses to low photopic conditions is instantaneous. After a change to scotopic conditions, rod driven responses change with a time course of several minutes. Responses to white light are cone driven at 8.8 cd/m2 and rod driven at 0.4 cd/m2.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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