It is known that all sensory information is input to the brain
as neural spike sequences. Now, to distinguish between the spike
sequences generated by retinal red/blue/green cone cells from
each other, and these from the cochlear (inner ear) hair cells,
and so on, some sort of encoding scheme must be used. To further
clarify, in the case of retinal cone cells, the rate of incident
light quanta in a given energy range, is the primary information
that is coded. But, if all 3 types of cone cells generated
identical responses for a given rate-of-incidence, like the CCD
pixels in our digital cameras do, then there would be no way for
upstream neurons to tell what type of cone cell a spike sequence
came from. Instead, my guess is that, each type of cone cell
encodes the rate-of-incidence in its own characteristic way,
similar to how different types of musical instruments sound
differently, even when playing the same pitch at the same
intensity, via timbre. Is there evidence that each sensory
neuron type has a chara