A “Melanopic” Spectral Efficiency Function Predicts the Sensitivity of Melanopsin Photoreceptors to Polychromatic Lights

  title={A “Melanopic” Spectral Efficiency Function Predicts the Sensitivity of Melanopsin Photoreceptors to Polychromatic Lights},
  author={Jazi al Enezi and Victoria Revell and Timothy Matthew Brown and Jonathan Wynne and Luc Schlangen and Robert James Lucas},
  journal={Journal of Biological Rhythms},
  pages={314 - 323}
Photoreception in the mammalian retina is not restricted to rods and cones but extends to a small number of intrinsically photosensitive retinal ganglion cells expressing the photopigment melanopsin. These mRGCs are especially important contributors to circadian entrainment, the pupil light reflex, and other so-called nonimage-forming (NIF) responses. The spectral sensitivity of melanopsin phototransduction has been addressed in several species by comparing responses to a range of monochromatic… 

Figures from this paper

The Melanopic Sensitivity Function Accounts for Melanopsin-Driven Responses in Mice under Diverse Lighting Conditions

VZλ provides the best available description of the spectral sensitivity of at least one aspect of the visual response in mice with functional rods and cones: tonic firing activity in the lateral geniculate nuclei, which establishes VZλ as an important new approach for light measurement with widespread practical utility.

Melanopsin-Based Brightness Discrimination in Mice and Humans

Melanopsin sensitivity in the human visual system

This work addresses the question of human melanopsin sensitivity and function in vivo using a spectrally tunable light source and the method of silent substitution, allowing for the selective stimulation of melanopigment in the human retina, in combination of pupillometry, psychophysics, and BOLD functional neuroimaging (fMRI).

Prolonged Inner Retinal Photoreception Depends on the Visual Retinoid Cycle

Electrophysiological and behavioral evidence is presented that ipRGCs depend on the RPE to continuously regenerate melanopsin during intense prolonged photostimulation and implications for RPE-related eye diseases and the acne drug isotretinoin are discussed.

A quantitative analysis of the contribution of melanopsin to brightness perception

The results suggest that melanopsin signals play a crucial role in the estimation of the absolute intensity of the light environment by obtaining absolute brightness information even when cones are adapted by light.

Melanopsin and Cone Photoreceptor Inputs to the Afferent Pupil Light Response

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.

Optimizing methods to isolate melanopsin-directed responses.

It is shown that adapting chromaticities used in silent-substitution methods can deviate by up to 54% in luminance when estimated with the individual and standard observer functions, which leads to inadvertent cone intrusions in the visual functions measured with melanopsin-directed stimuli.

A five-primary photostimulator suitable for studying intrinsically photosensitive retinal ganglion cell functions in humans.

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 is introduced.

The Method of Silent Substitution for Examining Melanopsin Contributions to Pupil Control

The method of silent substitution uses pairs of lights (“metamers”) to selectively stimulate a given class of photoreceptors while keeping the activation of all others constant.



Photon capture and signalling by melanopsin retinal ganglion cells

Fundamental parameters governing intrinsic light responses and associated spike generation of retinal ganglion cells are reported, finding that a flash causing a few hundred isomerized melanopsin molecules in a retina is sufficient for reaching threshold for the pupillary light reflex.

Melanopsin-Containing Retinal Ganglion Cells: Architecture, Projections, and Intrinsic Photosensitivity

It is shown that melanopsin is present in cell bodies, dendrites, and proximal axonal segments of a subset of rat RGCs, most likely the visual pigment of phototransducing R GCs that set the circadian clock and initiate other non–image-forming visual functions.

Melanopsin and rod–cone photoreceptive systems account for all major accessory visual functions in mice

The rod–cone and melanopsin systems together seem to provide all of the photic input for these accessory visual functions such as pupillary light reflex and circadian photo-entrainment.

Melanopsin-expressing ganglion cells in primate retina signal colour and irradiance and project to the LGN

An anatomically distinct population of ‘giant’, melanopsin-expressing ganglion cells in the primate retina that, in addition to being intrinsically photosensitive, are strongly activated by rods and cones, and display a rare, S-Off, (L + M)-On type of colour-opponent receptive field.

Intrinsic and extrinsic light responses in melanopsin-expressing ganglion cells during mouse development.

Results demonstrate that ipRGCs make use of melanopsin for phototransduction before eye opening and that these cells further integrate signals derived from the outer retina as the retina matures.

Diminished Pupillary Light Reflex at High Irradiances in Melanopsin-Knockout Mice

It is reported that in mice with the melanopsin gene ablated, RGCs retrograde-labeled from the suprachiasmatic nuclei were no longer intrinsically photosensitive, although their number, morphology, and projections were unchanged.

Melanopsin and inner retinal photoreception

A review of some of the landmark discoveries in this fast developing field of intrinsically photosensitive retinal ganglion cells, paying particular emphasis to recent findings and key areas for future investigation.