Limits...
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.

Show MeSH

Related in: MedlinePlus

Rods Define Circadian Responses at Moderate IrradiancesRepresentative double plotted actograms of wheel-running activity from the same Opn1mwR mouse exposed to 15 min pulses of 500 nm (1011 photons/cm2/s; A) or 650 nm (1012 photons/cm2/s; B) light at CT16 show a marked phase delay to the shorter, but not the longer, wavelength. The first 10–12 days show stable entrainment to a 12 hr:12 hr LD cycle (depicted as open/closed bars at the top of each panel), before release into DD at time indicated by arrow. Green/red circles represent the time of light exposure, with lines drawn through activity onsets before and after this pulse revealing the magnitude of the phase shift. (C) Irradiance response curves for phase delays elicited (mean ± SEM; n = 3–8) by 15 min pulses at CT16 using this paradigm in Opn1mwR mice reveal substantially reduced sensitivity to 650 nm light compared with 500 nm. Correcting for the relative sensitivity of cones at this wavelength was insufficient to account for the poor long-wavelength sensitivity. Responses to 500 nm were not altered by inclusion of 600 nm light at 10× higher irradiance (500+600 nm curve), confirming that cones make neither a strong stimulatory nor inhibitory contribution to this response. (D) Correcting the 650 nm irradiance response curve for the relative sensitivity of rods or melanopsin at this wavelength suggests that rods define the sensitivity of this response.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2875410&req=5

fig3: Rods Define Circadian Responses at Moderate IrradiancesRepresentative double plotted actograms of wheel-running activity from the same Opn1mwR mouse exposed to 15 min pulses of 500 nm (1011 photons/cm2/s; A) or 650 nm (1012 photons/cm2/s; B) light at CT16 show a marked phase delay to the shorter, but not the longer, wavelength. The first 10–12 days show stable entrainment to a 12 hr:12 hr LD cycle (depicted as open/closed bars at the top of each panel), before release into DD at time indicated by arrow. Green/red circles represent the time of light exposure, with lines drawn through activity onsets before and after this pulse revealing the magnitude of the phase shift. (C) Irradiance response curves for phase delays elicited (mean ± SEM; n = 3–8) by 15 min pulses at CT16 using this paradigm in Opn1mwR mice reveal substantially reduced sensitivity to 650 nm light compared with 500 nm. Correcting for the relative sensitivity of cones at this wavelength was insufficient to account for the poor long-wavelength sensitivity. Responses to 500 nm were not altered by inclusion of 600 nm light at 10× higher irradiance (500+600 nm curve), confirming that cones make neither a strong stimulatory nor inhibitory contribution to this response. (D) Correcting the 650 nm irradiance response curve for the relative sensitivity of rods or melanopsin at this wavelength suggests that rods define the sensitivity of this response.

Mentions: The same (M1) class of mRGC is responsible for routing rod and cone input to both the circadian clock and that portion of the pretectum responsible for the PLR (the oliviary pretectal nuclei shell; Baver et al., 2008; Güler et al., 2008). To establish whether cones contribute to circadian photoentrainment, we set out to determine whether that response showed an equivalent red shift in sensitivity in Opn1mwR mice. To this end, we constructed irradiance response curves for phase shifts in the free-running locomotor activity rhythm in Opn1mwR mice elicited by 15 min 500 or 650 nm stimuli presented in the early subjective night (CT16). As expected, 500 nm stimuli induced marked phase delays whose magnitude was irradiance dependent (Figure 3). Strikingly however, Opn1mwR mice showed very poor sensitivity to 650 nm. Significant phase delays were elicited only by bright (>1013 photons/cm2/s) stimuli, representing an increase in threshold irradiance of at least 1000× compared to 500 nm. This is much greater than that predicted for a response driven by red cones (Figure 3). Surprisingly, therefore, it seems that cones do not make a significant contribution to this assay of circadian photoentrainment even when presented with stimuli that lie within the photopic range.


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)

Rods Define Circadian Responses at Moderate IrradiancesRepresentative double plotted actograms of wheel-running activity from the same Opn1mwR mouse exposed to 15 min pulses of 500 nm (1011 photons/cm2/s; A) or 650 nm (1012 photons/cm2/s; B) light at CT16 show a marked phase delay to the shorter, but not the longer, wavelength. The first 10–12 days show stable entrainment to a 12 hr:12 hr LD cycle (depicted as open/closed bars at the top of each panel), before release into DD at time indicated by arrow. Green/red circles represent the time of light exposure, with lines drawn through activity onsets before and after this pulse revealing the magnitude of the phase shift. (C) Irradiance response curves for phase delays elicited (mean ± SEM; n = 3–8) by 15 min pulses at CT16 using this paradigm in Opn1mwR mice reveal substantially reduced sensitivity to 650 nm light compared with 500 nm. Correcting for the relative sensitivity of cones at this wavelength was insufficient to account for the poor long-wavelength sensitivity. Responses to 500 nm were not altered by inclusion of 600 nm light at 10× higher irradiance (500+600 nm curve), confirming that cones make neither a strong stimulatory nor inhibitory contribution to this response. (D) Correcting the 650 nm irradiance response curve for the relative sensitivity of rods or melanopsin at this wavelength suggests that rods define the sensitivity of this response.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2875410&req=5

fig3: Rods Define Circadian Responses at Moderate IrradiancesRepresentative double plotted actograms of wheel-running activity from the same Opn1mwR mouse exposed to 15 min pulses of 500 nm (1011 photons/cm2/s; A) or 650 nm (1012 photons/cm2/s; B) light at CT16 show a marked phase delay to the shorter, but not the longer, wavelength. The first 10–12 days show stable entrainment to a 12 hr:12 hr LD cycle (depicted as open/closed bars at the top of each panel), before release into DD at time indicated by arrow. Green/red circles represent the time of light exposure, with lines drawn through activity onsets before and after this pulse revealing the magnitude of the phase shift. (C) Irradiance response curves for phase delays elicited (mean ± SEM; n = 3–8) by 15 min pulses at CT16 using this paradigm in Opn1mwR mice reveal substantially reduced sensitivity to 650 nm light compared with 500 nm. Correcting for the relative sensitivity of cones at this wavelength was insufficient to account for the poor long-wavelength sensitivity. Responses to 500 nm were not altered by inclusion of 600 nm light at 10× higher irradiance (500+600 nm curve), confirming that cones make neither a strong stimulatory nor inhibitory contribution to this response. (D) Correcting the 650 nm irradiance response curve for the relative sensitivity of rods or melanopsin at this wavelength suggests that rods define the sensitivity of this response.
Mentions: The same (M1) class of mRGC is responsible for routing rod and cone input to both the circadian clock and that portion of the pretectum responsible for the PLR (the oliviary pretectal nuclei shell; Baver et al., 2008; Güler et al., 2008). To establish whether cones contribute to circadian photoentrainment, we set out to determine whether that response showed an equivalent red shift in sensitivity in Opn1mwR mice. To this end, we constructed irradiance response curves for phase shifts in the free-running locomotor activity rhythm in Opn1mwR mice elicited by 15 min 500 or 650 nm stimuli presented in the early subjective night (CT16). As expected, 500 nm stimuli induced marked phase delays whose magnitude was irradiance dependent (Figure 3). Strikingly however, Opn1mwR mice showed very poor sensitivity to 650 nm. Significant phase delays were elicited only by bright (>1013 photons/cm2/s) stimuli, representing an increase in threshold irradiance of at least 1000× compared to 500 nm. This is much greater than that predicted for a response driven by red cones (Figure 3). Surprisingly, therefore, it seems that cones do not make a significant contribution to this assay of circadian photoentrainment even when presented with stimuli that lie within the photopic range.

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