Andrew Huberman· PhD
We found that a small subset of these ganglion cells are themselves photoreceptors that were completely missed in the retina. And these are the photoreceptors that relay light environment subconsciously to the areas in the brain that have and house the circadian clock or the circadian pacemaker, which adjusts all the clocks in our bodies to the central brain clock that allows them to entrain to the 24 hour light-dark cycle.