Effects of flickering light stimulation on retinal blood flow and full-field electroretinogram in mice

Purpose To investigate the effects of brief flickering light stimulation (FLS) on retinal electrophysiology and retinal blood flow (RBF) in normal C57BL6J mice. Methods RBF and full-field electroretinography (ffERG) were measured before and after a 60 second FLS (12 Hz, 0.1 cd·s/m 2 ) in a cohort of 8-12-weeks old C57BL6J mice ( n =10) under anaesthetic and light-adapted conditions. A separate set of age-matched mice ( n =9) underwent RBF and ffERG measurements before and after steady light stimulation (SLS) at 1 cd/m 2 under similar conditions. The changes in RBF (arterial and venous flow) as well as the amplitudes and implicit times of the a-wave, b-wave, oscillatory potentials (OPs), and photopic negative response (PhNR) were analyzed. Results FLS significantly increased both arterial ( p =0.003) and venous ( p =0.018) blood flow as well as b-wave amplitudes ( p =0.017) compared to SLS, which did not have any significant changes in either RBF or ERG. However, no significant differences were found in other ffERG responses (amplitudes and implicit times of a-wave, OPs, and PhNR, as well as b-wave implicit time) between the two groups after light stimulation. An increase in b-wave amplitude was positively associated with an increase in both arterial (r=0.655, p =0.040) and venous blood flow (r=0.638, p =0.047) in the FLS group. Conclusions Our results suggest that transient FLS not only increases RBF but also enhances electro-retinal responses of the middle retinal layer, as shown by ffERG, thus demonstrating its substantial effects on both the vascular and neuronal components of retinal neurovascular coupling in mice.