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Sascha Klee, Dietmar Link, Patrick Bessler, Jens Haueisen; Measuring cone recovery kinetics after bleaching. Invest. Ophthalmol. Vis. Sci. 2013;54(15):2484. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Investigations on sensitivity changes of the human visual system between dark and light adaptation suggest faster recovery kinetics in cones than in rods. However, the different recovery behavior in konio- and parvocellular cells still needs to be investigated. In this work, we selectively suppress cone activity using an adaptation box and analyze the recovery kinetics based on the selective cone VEPs. The box allows the selective suppression of cone activity.
To selectively suppress cone activity we built a RGBW adaptation box (130cm x 80cm x 100cm) using Lambertian surface material. The included fluorescent tube system was controlled by a digitally addressable lighting interface and was adjusted to 1104lux at 436nm (B), 5483lux at 486nm/542nm (G), and 2857lux at 601nm/631nm (R). To verify the recovery kinetics we designed two selective stimulation sequences (S-cone and LM-cone) based on the silent substitution technique and studied three volunteers. After 10min of parvocellular bleaching a selective LM-cone stimulation with simultaneous EEG recording was conducted. After a break of 60min the same bleaching was combined with the S-cone stimulation. The procedure was analogously for the koniocellular cells.
We found a faster recovery kinetics in the parvocellular system. Small LM-cone responses were visible ≥8s after the bleaching while complete VEP of 10.5µV occurs after 11s. In koniocellular cells full recovery could be obtained ≥55s after the bleaching with amplitudes ≥6µV. The selective VEPs of the unbleached cone system were not reduced and already visible in the first averaging window.
We conclude that the new adaptation box is suitable for bleaching experiments. The faster recovery kinetic in the parvocellular system is consistent with findings of faster VEP latencies in LM-cone VEPs.
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