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Zele AJ, Adhikari P, Cao D, Feigl B. Melanopsin and Cone Photoreceptor Inputs to the Afferent Pupil Light Response. Front Neurol 2019; 10:529. [PMID: 31191431 PMCID: PMC6540681 DOI: 10.3389/fneur.2019.00529] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 05/03/2019] [Indexed: 11/20/2022] Open
Abstract
Background: Retinal photoreceptors provide the main stage in the mammalian eye for regulating the retinal illumination through changes in pupil diameter, with a small population of melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs) forming the primary afferent pathway for this response. The purpose of this study is to determine how melanopsin interacts with the three cone photoreceptor classes in the human eye to modulate the light-adapted pupil response. Methods: We investigated the independent and combined contributions of the inner and outer retinal photoreceptor inputs to the afferent pupil pathway in participants with trichromatic color vision using a method to independently control the excitations of ipRGCs, cones and rods in the retina. Results: We show that melanopsin-directed stimuli cause a transient pupil constriction generated by cones in the shadow of retinal blood vessels; desensitizing these penumbral cone signals uncovers a signature melanopsin pupil response that includes a longer latency (292 ms) and slower time (4.1x) and velocity (7.7x) to constriction than for cone-directed stimuli, and which remains sustained post-stimulus offset. Compared to melanopsin-mediated pupil responses, the cone photoreceptor-initiated pupil responses are more transient with faster constriction latencies, higher velocities and a secondary constriction at light offset. The combined pupil responses reveal that melanopsin signals are additive with the cone signals. Conclusions: The visual system uses the L–, M–, and S–cone photoreceptor inputs to the afferent pupil pathway to accomplish the tonic modulations of pupil size to changes in image contrast. The inner retinal melanopsin-expressing ipRGCs mediate the longer-term, sustained pupil constriction to set the light-adapted pupil diameter during extended light exposures.
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Affiliation(s)
- Andrew J Zele
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, QLD, Australia.,School of Optometry and Vision Science, Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Prakash Adhikari
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, QLD, Australia.,School of Optometry and Vision Science, Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Dingcai Cao
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, United States
| | - Beatrix Feigl
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, QLD, Australia.,School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, QLD, Australia.,Queensland Eye Institute, Brisbane, QLD, Australia
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Barrionuevo PA, Cao D. Luminance and chromatic signals interact differently with melanopsin activation to control the pupil light response. J Vis 2016; 16:29. [PMID: 27690169 PMCID: PMC5054726 DOI: 10.1167/16.11.29] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Intrinsically photosensitive retinal ganglion cells (ipRGCs) express the photopigment melanopsin. These cells receive afferent inputs from rods and cones, which provide inputs to the postreceptoral visual pathways. It is unknown, however, how melanopsin activation is integrated with postreceptoral signals to control the pupillary light reflex. This study reports human flicker pupillary responses measured using stimuli generated with a five-primary photostimulator that selectively modulated melanopsin, rod, S-, M-, and L-cone excitations in isolation, or in combination to produce postreceptoral signals. We first analyzed the light adaptation behavior of melanopsin activation and rod and cones signals. Second, we determined how melanopsin is integrated with postreceptoral signals by testing with cone luminance, chromatic blue-yellow, and chromatic red-green stimuli that were processed by magnocellular (MC), koniocellular (KC), and parvocellular (PC) pathways, respectively. A combined rod and melanopsin response was also measured. The relative phase of the postreceptoral signals was varied with respect to the melanopsin phase. The results showed that light adaptation behavior for all conditions was weaker than typical Weber adaptation. Melanopsin activation combined linearly with luminance, S-cone, and rod inputs, suggesting the locus of integration with MC and KC signals was retinal. The melanopsin contribution to phasic pupil responses was lower than luminance contributions, but much higher than S-cone contributions. Chromatic red-green modulation interacted with melanopsin activation nonlinearly as described by a “winner-takes-all” process, suggesting the integration with PC signals might be mediated by a postretinal site.
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Affiliation(s)
- Pablo A Barrionuevo
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, USAInstitute of Research in Light, Environment and Vision, National University of Tucumán - National Scientific and Technical Research Council, San Miguel de Tucumán, Tucumán
| | - Dingcai Cao
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, ://vpl.uic.edu/
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Keenan WT, Rupp AC, Ross RA, Somasundaram P, Hiriyanna S, Wu Z, Badea TC, Robinson PR, Lowell BB, Hattar SS. A visual circuit uses complementary mechanisms to support transient and sustained pupil constriction. eLife 2016; 5:e15392. [PMID: 27669145 PMCID: PMC5079752 DOI: 10.7554/elife.15392] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 09/22/2016] [Indexed: 12/22/2022] Open
Abstract
Rapid and stable control of pupil size in response to light is critical for vision, but the neural coding mechanisms remain unclear. Here, we investigated the neural basis of pupil control by monitoring pupil size across time while manipulating each photoreceptor input or neurotransmitter output of intrinsically photosensitive retinal ganglion cells (ipRGCs), a critical relay in the control of pupil size. We show that transient and sustained pupil responses are mediated by distinct photoreceptors and neurotransmitters. Transient responses utilize input from rod photoreceptors and output by the classical neurotransmitter glutamate, but adapt within minutes. In contrast, sustained responses are dominated by non-conventional signaling mechanisms: melanopsin phototransduction in ipRGCs and output by the neuropeptide PACAP, which provide stable pupil maintenance across the day. These results highlight a temporal switch in the coding mechanisms of a neural circuit to support proper behavioral dynamics.
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Affiliation(s)
| | - Alan C Rupp
- Department of Biology, Johns Hopkins University, Baltimore, United States
| | - Rachel A Ross
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, United States
- Department of Psychiatry, Massachusetts General Hospital, Boston, United States
| | - Preethi Somasundaram
- Department of Biological Sciences, University of Marlyand, Baltimore, United States
| | - Suja Hiriyanna
- National Eye Institute, National Institutes of Health, Bethesda, United States
| | - Zhijian Wu
- National Eye Institute, National Institutes of Health, Bethesda, United States
| | - Tudor C Badea
- National Eye Institute, National Institutes of Health, Bethesda, United States
| | - Phyllis R Robinson
- Department of Biological Sciences, University of Marlyand, Baltimore, United States
| | - Bradford B Lowell
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, United States
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, United States
- Program in Neuroscience, Harvard Medical School, Boston, United States
| | - Samer S Hattar
- Department of Biology, Johns Hopkins University, Baltimore, United States
- Department of Neuroscience, Johns Hopkins University, Baltimore, United States
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Collison FT, Park JC, Fishman GA, Stone EM, McAnany JJ. Two-color pupillometry in enhanced S-cone syndrome caused by NR2E3 mutations. Doc Ophthalmol 2016; 132:157-66. [PMID: 27033713 DOI: 10.1007/s10633-016-9535-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 03/22/2016] [Indexed: 11/29/2022]
Abstract
PURPOSE The purpose of this study was to evaluate pupillary light reflexes (PLRs) mediated by rod, cone, and intrinsically photosensitive retinal ganglion cell pathways as indices of outer- and inner-retinal function in patients who have enhanced S-cone syndrome (ESCS) due to NR2E3 mutations. METHODS Four patients with ESCS (ages 16-23 years) participated in the study. Subjects were tested with long- and short-wavelength single-flash full-field ERG stimuli under light-adapted conditions. They were also tested with an established pupillometry protocol involving 1-s duration, long- and short-wavelength stimuli under dark- and light-adapted conditions. The PLR was measured as a function of stimulus luminance. Transient PLRs were measured under all conditions, and sustained PLRs were measured under the highest luminance dark-adapted condition. RESULTS Two-color light-adapted full-field ERGs demonstrated larger amplitude responses for short-wavelength stimuli relative to long-wavelength stimuli of the same photopic luminance, with three of four ESCS patients having super-normal a-wave amplitudes to the short-wavelength stimulus. b/a wave ratios were reduced in all four cases. Transient PLRs elicited by low-luminance stimuli under dark-adapted conditions (rod-mediated) were unrecordable, whereas the sustained PLRs elicited by high-luminance stimuli (melanopsin-mediated) were normal. Cone-mediated PLRs were recordable for all four patients, but generally lower than normal in amplitude. However, the cone-mediated PLR was larger for the short-wavelength stimulus compared to the photopically matched long-wavelength stimulus at high luminances, a pattern that was not observed for control subjects. None of the PLR conditions demonstrated "super-normal" responses. CONCLUSION ESCS patients appear to have generally well-preserved cone- and melanopsin-mediated PLRs, indicating intact inner-retinal function. Two-color pupillometry demonstrates greater sensitivity to short-wavelength light under higher-luminance conditions and could complement the ERG as a tool for evaluating retinal function in ESCS.
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Affiliation(s)
- Frederick T Collison
- The Pangere Center for Hereditary Retinal Diseases, The Chicago Lighthouse, 1850 West Roosevelt Rd., Chicago, IL, 60608, USA
| | - Jason C Park
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, 1905 West Taylor St., Chicago, IL, 60612, USA
| | - Gerald A Fishman
- The Pangere Center for Hereditary Retinal Diseases, The Chicago Lighthouse, 1850 West Roosevelt Rd., Chicago, IL, 60608, USA. .,Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, 1905 West Taylor St., Chicago, IL, 60612, USA.
| | - Edwin M Stone
- Stephen A. Wynn Institute for Vision Research, Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, 375 Newton Rd. 4111 MERF, Iowa City, IA, 52242, USA
| | - J Jason McAnany
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, 1905 West Taylor St., Chicago, IL, 60612, USA
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Cao D, Nicandro N, Barrionuevo PA. A five-primary photostimulator suitable for studying intrinsically photosensitive retinal ganglion cell functions in humans. J Vis 2015; 15:15.1.27. [PMID: 25624466 DOI: 10.1167/15.1.27] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Intrinsically photosensitive retinal ganglion cells (ipRGCs) can respond to light directly through self-contained photopigment, melanopsin. IpRGCs also receive synaptic inputs from rods and cones. Thus, studying ipRGC functions requires a novel photostimulating method that can account for all of the photoreceptor inputs. Here, we introduced an inexpensive LED-based five-primary photostimulator that can control the excitations of rods, S-, M-, L-cones, and melanopsin-containing ipRGCs in humans at constant background photoreceptor excitation levels, a critical requirement for studying the adaptation behavior of ipRGCs with rod, cone, or melanopsin input. We described the theory and technical aspects (including optics, electronics, software, and calibration) of the five-primary photostimulator. Then we presented two preliminary studies using the photostimulator we have implemented to measure melanopsin-mediated pupil responses and temporal contrast sensitivity function (TCSF). The results showed that the S-cone input to pupil responses was antagonistic to the L-, M- or melanopsin inputs, consistent with an S-OFF and (L + M)-ON response property of primate ipRGCs (Dacey et al., 2005). In addition, the melanopsin-mediated TCSF had a distinctive pattern compared with L + M or S-cone mediated TCSF. Other than controlling individual photoreceptor excitation independently, the five-primary photostimulator has the flexibility in presenting stimuli modulating any combination of photoreceptor excitations, which allows researchers to study the mechanisms by which ipRGCs combine various photoreceptor inputs.
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Affiliation(s)
- Dingcai Cao
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Nathaniel Nicandro
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Pablo A Barrionuevo
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, USA
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Opponent melanopsin and S-cone signals in the human pupillary light response. Proc Natl Acad Sci U S A 2014; 111:15568-72. [PMID: 25313040 DOI: 10.1073/pnas.1400942111] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
In the human, cone photoreceptors (L, M, and S) and the melanopsin-containing, intrinsically photosensitive retinal ganglion cells (ipRGCs) are active at daytime light intensities. Signals from cones are combined both additively and in opposition to create the perception of overall light and color. Similar mechanisms seem to be at work in the control of the pupil's response to light. Uncharacterized however, is the relative contribution of melanopsin and S cones, with their overlapping, short-wavelength spectral sensitivities. We measured the response of the human pupil to the separate stimulation of the cones and melanopsin at a range of temporal frequencies under photopic conditions. The S-cone and melanopsin photoreceptor channels were found to be low-pass, in contrast to a band-pass response of the pupil to L- and M-cone signals. An examination of the phase relationships of the evoked responses revealed that melanopsin signals add with signals from L and M cones but are opposed by signals from S cones in control of the pupil. The opposition of the S cones is revealed in a seemingly paradoxical dilation of the pupil to greater S-cone photon capture. This surprising result is explained by the neurophysiological properties of ipRGCs found in animal studies.
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McDougal DH, Gamlin PD. The influence of intrinsically-photosensitive retinal ganglion cells on the spectral sensitivity and response dynamics of the human pupillary light reflex. Vision Res 2011; 50:72-87. [PMID: 19850061 DOI: 10.1016/j.visres.2009.10.012] [Citation(s) in RCA: 161] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Revised: 10/12/2009] [Accepted: 10/13/2009] [Indexed: 11/15/2022]
Abstract
Historically, it was assumed that the light-evoked neural signals driving the human pupillary light reflex (PLR) originated exclusively from rod and cone photoreceptors. However, a novel melanopsin-containing photoreceptive cell class has recently been discovered in the mammalian retina. These intrinsically-photosensitive retinal ganglion cells (ipRGCs) project to the pretectum, the retinorecipient area of the brain responsible for the PLR. This study was therefore designed to examine the relative contribution of rod, cone and the melanopsin photoresponses of ipRGCs to the human PLR. We establish that the melanopsin photoresponse of ipRGCs contributes significantly to the maintenance of half maximal pupilloconstriction in response to light stimuli of 30s or longer, even at low photopic irradiances. Furthermore, we show that the melanopsin photoresponse contributes significantly to three-quarter maximal pupilloconstriction in response to light stimuli as short as 2s. We also demonstrate that cone photoresponses driving pupilloconstriction adapt considerably and contribute little after 30s, but rod photoresponses adapt less and contribute significantly to the maintenance of pupilloconstriction in response to steady-state light stimuli at irradiance levels which are below the threshold of the melanopsin photoresponse.
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Affiliation(s)
- David H McDougal
- Laboratory of Autonomic Neurosciences, Pennington Biomedical Research, Center, 6400 Perkins Road, Baton Rouge, LA 70808, United States
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Sustained pupillary constrictions mediated by an L- and M-cone opponent process. Vision Res 2010; 50:489-96. [PMID: 20060405 DOI: 10.1016/j.visres.2010.01.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Revised: 12/11/2009] [Accepted: 01/04/2010] [Indexed: 11/30/2022]
Abstract
We show that irradiance-coding alone cannot explain the sustained pupillary constrictions evoked by chromatic and luminance variations in a stimulus. For example, stimulus modulations that decremented the contrasts in L- and M-cones as well as rods and melanopsin photoreceptors produced sustained constrictions rather than the predicted dilations. Although the sustained responses are unidirectional, we confirm that they are at least partially mediated by an L- and M-cone opponent interaction. We discuss the implications of sustained unidirectional chromatic responses in view of the function of the pupil to improve the clarity of vision.
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Young RSL, Kimura E. Pupillary correlates of light-evoked melanopsin activity in humans. Vision Res 2008; 48:862-71. [PMID: 18262584 DOI: 10.1016/j.visres.2007.12.016] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2007] [Revised: 12/20/2007] [Accepted: 12/21/2007] [Indexed: 10/22/2022]
Abstract
We investigated whether cones are the only photosensitive process mediating the photopic pupillary light reflex. New analyses were performed on previously published recordings, focusing on those evoked by the onset of photopically equated short- and long-wavelength stimuli. Comparisons between responses revealed contraction differences that slowly grew to a peak and gradually declined. The late contraction was associated with short wavelengths and appeared mostly at the higher stimulus intensities. We conclude that cones are not the only photoreception process mediating the photopic ON-reflex and infer that melanopsin is another. Melanopsin contributes to the steady-state pupil size in daylight illumination.
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Affiliation(s)
- Rockefeller S L Young
- Department of Ophthalmology & Visual Sciences, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
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Yao G, Zhang K, Bellassai M, Chang B, Lei B. Ultraviolet light-induced and green light-induced transient pupillary light reflex in mice. Curr Eye Res 2007; 31:925-33. [PMID: 17114118 DOI: 10.1080/02713680600932308] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PURPOSE To study UV light-induced and green light-induced pupillary light reflex (PLR) in mice and to measure the illumination thresholds of rod-mediated and cone-mediated PLR responses. METHODS We measured dark-adapted transient PLR- in C57BL/6 mice elicited with ultraviolet and green light over an intensity range of 9 log units. To assist in isolating the responses mediated by rods and cones, we studied the PLRs in mouse models presenting pure cone and pure rod functions. We also characterized ERG signals in these mice under the same experimental conditions. RESULTS The UV light-induced transient PLR has identical intensity-response curves as green light-induced PLR in all the three mice strains. The threshold (5% PLR) of rod-driven PLR is 107 approximately 108 photons cm2 s-1, which is 1 approximately 2 log units lower than the dark-adapted ERG b-wave. The threshold of cone-driven PLR is approximately 1012.5 photons cm-2 s-1 and is similar to that of the cone ERG. CONCLUSIONS We demonstrated that mice have PLR responses under UV stimulation. The cone-elicited PLRs have a threshold that is approximately 5 log units higher than that of rod-elicited PLR at both UV and green wavelengths. We observed a divergence between the spectra responses in PLR and ERG. However, the mechanism and implications of this phenomenon are yet to be identified.
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Affiliation(s)
- Gang Yao
- Department of Biological Engineering, University of Missouri Columbia, Columbia, MO 65211-0001, USA
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