title: Dynamic near-infrared imaging reveals transient phototropic change in retinal rod photoreceptors.
abstract: Stiles-Crawford effect (SCE) is exclusively observed in cone photoreceptors, but why the SCE is absent in rod photoreceptors is still a mystery. In this study, we employed dynamic near infrared light imaging to monitor photoreceptor kinetics in freshly isolated frog and mouse retinas stimulated by oblique visible light flashes. It was observed that retinal rods could rapidly (onset: ∼10 ms for frog and 5 ms for mouse; time-to-peak: ∼200 ms for frog and 30 ms for mouse) shift toward the direction of the visible light, which might quickly compensate for the loss of luminous efficiency due to oblique illumination. In contrast, such directional movement was negligible in retinal cones. Moreover, transient rod phototropism could contribute to characteristic intrinsic optical signal (IOS). We anticipate that further study of the transient rod phototropism may not only provide insight into better understanding of the nature of vision but also promise an IOS biomarker for functional mapping of rod physiology at high resolution.
authors.affiliation: University of Alabama at Birmingham, Department of Biomedical Engineering, Birmingham, Alabama 35294.
authors.forename: Rongwen
authors.initials: R
authors.lastname: Lu
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Levy
authors.forename: Qiuxiang
authors.initials: Q
authors.lastname: Zhang
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Pittler
authors.forename: Xincheng
authors.initials: X
authors.lastname: Yao
mesh_terms: D000465:Algorithms; D000818:Animals; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008029:Lighting; D051379:Mice; D010775:Photic Stimulation; D018524:Phototropism / Q000502:physiology*; D011894:Rana pipiens; D012160:Retina / Q000166:cytology / Q000502:physiology; D017948:Retinal Rod Photoreceptor Cells / Q000502:physiology*; D012815:Signal Processing, Computer-Assisted; D019265:Spectroscopy, Near-Infrared / Q000379:methods*