I have questions regarding the signal between the retina and other parts of the brain. There are two types bipolar cells which are excited by light or darkness to the retina.
Question: Do these form different signal frequencies over the nerve channels?
This is my understanding from resources.
Retinal ganglion cells spontaneously fire action potentials at a base rate while at rest. Excitation of retinal ganglion cells results in an increased firing rate while inhibition results in a depressed rate of firing.
It’s my understanding the photoreceptors in the eye have an opsin pigment molecule which experiences a change in geometry when an electromagnetic wave passes through, pushing on the photoreceptor’s body. A potential difference in voltage occurs which causes the photoreceptor to release glutamate, an exciting neurotransmitter, or GABA an inhibitory one to the electric synapses of the bipolar cells via synapses.
One type of bipolar cell gets excited by light while the other inhibited. Either one releases a neurotransmitter to the synapses of an ion channel. The ion channel creates potential difference, sending a signal or action potential through from the soma, to the axon, to dendrites and to its receptor destination. The above quote suggests that the action potential is “frequency shit key” modulated, with a baseline frequency, then a higher or lower frequency depending on presence of a particular light wavelength. The photoreceptor outputs an exciting neurotransmitter with no light, inhibitory with light.