The relationship between slow photoresponse recovery rate and temporal resolution of vision.
The rate at which photoreceptors recover from excitation is thought to be critical for setting the temporal resolution of vision. Indeed, mutations in RGS9 (regulator of G-protein signaling 9) and R9AP (RGS9 anchor protein) proteins mediating rapid photoresponse recovery impair patients' ability to see moving objects. In this study, we analyzed temporal properties of retinal sensitivity and spatiotemporal aspects of visual behavior in R9AP knock-out mice. Surprisingly, we have found that this knock-out does not affect dim-light vision mediated by rods acting as single-photon counters. Under these conditions, vision was also unaffected in mice overexpressing R9AP in rods, which causes accelerated photoresponse recovery. However, in brighter light, slow photoresponse recovery in rods and cones impaired visual responses to high temporal frequency stimuli, as reported for the daylight vision of human patients. Therefore, the speed of photoresponse recovery can affect temporal resolution and motion detection when photoreceptors integrate signals from multiple photons but not when they act as single-photon counters.
Center for Vision Research and State University of New York (SUNY) Eye Institute, Department of Ophthalmology, SUNY Upstate Medical University, Syracuse, New York 13210, USA.
Yumiko
Y
Umino
Rolf
R
Herrmann
Ching-Kang
CK
Chen
Robert B
RB
Barlow
Vadim Y
VY
Arshavsky
Eduardo
E
Solessio
D000221:Adaptation, Ocular / Q000235:genetics / Q000502:physiology*; D000818:Animals; D005260:Female; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000172:deficiency / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009039:Motion Perception / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods*; D020419:Photoreceptor Cells, Vertebrate / Q000502:physiology*; D013997:Time Factors; D014785:Vision, Ocular / Q000502:physiology*
D008565:Membrane Proteins; C508769:R9AP protein, mouse