Simple Rod Photoreceptor Circuit

One NeuroBytes rod photoreceptor is connected from the dark output through an excitatory neurotransmitter cable to a short interneuron dendrite. In the dark, the interneuron fires regular action potentials. As the flashlight beam sweeps across the rod photoreceptor light detector, the action potentials slow and then stop. This happens because the dark output is inactive in the light. Real rod photoreceptors work in a similar way, releasing neurotransmitters in the dark, and reducing their release in the light.