The circadian rhythm is reset by input from special ganglion cells in the retina. These ganglion cells are unusual in that they ____.
A) receive input from only cones, not rods
B) are located only in a doughnut-shaped band surrounding the fovea
C) respond directly to light, but respond very slowly
D) become active only at night or in very dim light

Question

Quizplus · Accepted Answer

These ganglion cells are unique because they can directly respond to light, albeit their response is much slower compared to the traditional photoreceptor cells (rods and cones) in the retina. This capability allows them to play a crucial role in regulating the circadian rhythm by sensing overall light levels in the environment, rather than forming images.

The Circadian Rhythm Is Reset by Input from Special Ganglion