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Distinct contributions of rod, cone, and melanopsin photoreceptors to encoding irradiance.

Lall GS, Revell VL, Momiji H, Al Enezi J, Altimus CM, Güler AD, Aguilar C, Cameron MA, Allender S, Hankins MW, Lucas RJ - Neuron (2010)

Bottom Line: These photoreceptors define circadian responses at very dim "scotopic" light levels but also at irradiances at which pattern vision relies heavily on cones.By contrast, cone input to irradiance responses dissipates following light adaptation to the extent that these receptors make a very limited contribution to circadian and pupillary light responses under these conditions.Our data provide new insight into retinal circuitry upstream of mRGCs and optimal stimuli for eliciting irradiance responses.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Life Sciences, AV Hill Building, University of Manchester, Manchester M13 9PT, UK.

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Responses to Constant Light Reveal a High Sensitivity Rod Input to the Circadian Clock(A and B) Representative actograms of wheel-running activity reveal irradiance-dependent increases in circadian period (τ) of Opn1mwR mice exposed to constant 644 nm (A) or 498 nm (B) light. Consecutive reductions in light intensity are depicted as reductions in background colored shading. The final 10 days of both records (gray shading) were collected in DD.(C) Irradiance response relationships for τ (estimated by periodogram analysis of activity records as shown in A and B) at 498 and 644 nm (mean ± SEM; n = 3–6), revealed substantially reduced sensitivity at the longer wavelength.(D) The difference in responsiveness to these two wavelengths could not be adequately accounted for by correcting for the relative sensitivity of either melanopsin or cones.(E) On the other hand, the curves became superimposed when corrected for rods. Arrow represents the estimated threshold for rod vision in mice (Nathan et al., 2006).
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fig4: Responses to Constant Light Reveal a High Sensitivity Rod Input to the Circadian Clock(A and B) Representative actograms of wheel-running activity reveal irradiance-dependent increases in circadian period (τ) of Opn1mwR mice exposed to constant 644 nm (A) or 498 nm (B) light. Consecutive reductions in light intensity are depicted as reductions in background colored shading. The final 10 days of both records (gray shading) were collected in DD.(C) Irradiance response relationships for τ (estimated by periodogram analysis of activity records as shown in A and B) at 498 and 644 nm (mean ± SEM; n = 3–6), revealed substantially reduced sensitivity at the longer wavelength.(D) The difference in responsiveness to these two wavelengths could not be adequately accounted for by correcting for the relative sensitivity of either melanopsin or cones.(E) On the other hand, the curves became superimposed when corrected for rods. Arrow represents the estimated threshold for rod vision in mice (Nathan et al., 2006).

Mentions: To investigate the photoreceptors regulating the clock in more detail, we turned to a different assay of circadian photoentrainment. When exposed to constant light, the period (τ) of mouse circadian rhythms lengthens according to Aschoff's rule (Daan and Pittendrigh, 1976). To determine the photoreceptors driving this response, we described its irradiance dependence in Opn1mwR mice exposed to either continuous mid- (498 nm) or long- (644 nm) wavelength light. Both wavelengths effectively lengthened τ (Figure 4). However, there was a marked decrease in sensitivity to the longer wavelength. Matching the irradiance response relationships for the relative sensitivity of red cones revealed that there was no irradiance at which τ was defined by cone photoreception (Figure 4D; F-test statistic; slopes at 498 nm and 644 nm similar, p > 0.05; intercepts significantly different [p < 0.001] when corrected for red cone spectral sensitivity). The curves were more equivalent when normalized for melanopsin sensitivity, but responses were clearly enhanced at 650 nm compared to that predicted for melanopsin, especially at lower irradiances (Figure 4C; F-test comparing intercepts, p < 0.001). By contrast, the curves became superimposed when corrected for rod sensitivity (Figure 4E; F-test comparing intercepts, p > 0.05), confirming that rod activity dominates this assay of photoentrainment, at least at low-moderate irradiances. The threshold for τ lengthening was around that reported for scotopic vision in mice (Nathan et al., 2006; Sampath et al., 2005), suggesting that mRGCs receive input from the highest-sensitivity rod pathways.


Distinct contributions of rod, cone, and melanopsin photoreceptors to encoding irradiance.

Lall GS, Revell VL, Momiji H, Al Enezi J, Altimus CM, Güler AD, Aguilar C, Cameron MA, Allender S, Hankins MW, Lucas RJ - Neuron (2010)

Responses to Constant Light Reveal a High Sensitivity Rod Input to the Circadian Clock(A and B) Representative actograms of wheel-running activity reveal irradiance-dependent increases in circadian period (τ) of Opn1mwR mice exposed to constant 644 nm (A) or 498 nm (B) light. Consecutive reductions in light intensity are depicted as reductions in background colored shading. The final 10 days of both records (gray shading) were collected in DD.(C) Irradiance response relationships for τ (estimated by periodogram analysis of activity records as shown in A and B) at 498 and 644 nm (mean ± SEM; n = 3–6), revealed substantially reduced sensitivity at the longer wavelength.(D) The difference in responsiveness to these two wavelengths could not be adequately accounted for by correcting for the relative sensitivity of either melanopsin or cones.(E) On the other hand, the curves became superimposed when corrected for rods. Arrow represents the estimated threshold for rod vision in mice (Nathan et al., 2006).
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fig4: Responses to Constant Light Reveal a High Sensitivity Rod Input to the Circadian Clock(A and B) Representative actograms of wheel-running activity reveal irradiance-dependent increases in circadian period (τ) of Opn1mwR mice exposed to constant 644 nm (A) or 498 nm (B) light. Consecutive reductions in light intensity are depicted as reductions in background colored shading. The final 10 days of both records (gray shading) were collected in DD.(C) Irradiance response relationships for τ (estimated by periodogram analysis of activity records as shown in A and B) at 498 and 644 nm (mean ± SEM; n = 3–6), revealed substantially reduced sensitivity at the longer wavelength.(D) The difference in responsiveness to these two wavelengths could not be adequately accounted for by correcting for the relative sensitivity of either melanopsin or cones.(E) On the other hand, the curves became superimposed when corrected for rods. Arrow represents the estimated threshold for rod vision in mice (Nathan et al., 2006).
Mentions: To investigate the photoreceptors regulating the clock in more detail, we turned to a different assay of circadian photoentrainment. When exposed to constant light, the period (τ) of mouse circadian rhythms lengthens according to Aschoff's rule (Daan and Pittendrigh, 1976). To determine the photoreceptors driving this response, we described its irradiance dependence in Opn1mwR mice exposed to either continuous mid- (498 nm) or long- (644 nm) wavelength light. Both wavelengths effectively lengthened τ (Figure 4). However, there was a marked decrease in sensitivity to the longer wavelength. Matching the irradiance response relationships for the relative sensitivity of red cones revealed that there was no irradiance at which τ was defined by cone photoreception (Figure 4D; F-test statistic; slopes at 498 nm and 644 nm similar, p > 0.05; intercepts significantly different [p < 0.001] when corrected for red cone spectral sensitivity). The curves were more equivalent when normalized for melanopsin sensitivity, but responses were clearly enhanced at 650 nm compared to that predicted for melanopsin, especially at lower irradiances (Figure 4C; F-test comparing intercepts, p < 0.001). By contrast, the curves became superimposed when corrected for rod sensitivity (Figure 4E; F-test comparing intercepts, p > 0.05), confirming that rod activity dominates this assay of photoentrainment, at least at low-moderate irradiances. The threshold for τ lengthening was around that reported for scotopic vision in mice (Nathan et al., 2006; Sampath et al., 2005), suggesting that mRGCs receive input from the highest-sensitivity rod pathways.

Bottom Line: These photoreceptors define circadian responses at very dim "scotopic" light levels but also at irradiances at which pattern vision relies heavily on cones.By contrast, cone input to irradiance responses dissipates following light adaptation to the extent that these receptors make a very limited contribution to circadian and pupillary light responses under these conditions.Our data provide new insight into retinal circuitry upstream of mRGCs and optimal stimuli for eliciting irradiance responses.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Life Sciences, AV Hill Building, University of Manchester, Manchester M13 9PT, UK.

Show MeSH
Related in: MedlinePlus