Encoding of environmental illumination by primate melanopsin neurons

Light regulates physiology, mood, and behavior through signals sent to the brain by intrinsically photosensitive retinal ganglion cells (ipRGCs). How primate ipRGCs sense light is unclear, as they are rare and challenging to target for electrophysiological recording. We developed a method of acute identification within the live, ex vivo retina. Using it, we found that ipRGCs of the macaque monkey are highly specialized to encode irradiance (the overall intensity of illumination) by blurring spatial, temporal, and chromatic features of the visual scene. We describe mechanisms at the molecular, cellular, and population scales that support irradiance encoding across orders-of-magnitude changes in light intensity. These mechanisms are conserved quantitatively across the similar to 70 million years of evolution that separate macaques from mice.

Automated summary

Primate ipRGCs regulate physiology, mood, and behavior by sending signals to the brain. It has been discovered that macaque ipRGCs encode irradiance by blurring spatial, temporal, and chromatic features, and this encoding mechanism is conserved across millions of years of evolution.