The cascade of a visual signal from the photon to the perceived color. The pathway is often described as the chain of cells that the signal travels through on its way to the brain:
- Photoreceptor Cell – Rods and Cones
- Horizontal Cell – Sometimes
- Bipolar Cell
- Amacrine Cell – Sometimes
- Retinal Ganglion Cell – comprising the optic nerve
However, it can also be described more finely as the molecular chain of events within the Photoreceptor:
- Chromophore – catches the photon
- Opsin – tunes the Chromophore Peak Wavelength and interfaces with Transducin
- Transducin – a type of G-protein
- Phosphodiesterase – converts cGMP to GMP
- Sodium Channels – on the Photoreceptor close, leading to hyperpolarization (a potential across the cell membrane).
- Synapse – the photoreceptor releases Glutamate to trigger the Bipolar Cell.