Retinal Circuitry - Is There a Fundamental Mystery?

We know an awful lot about the computations that occur on the front end. But i don't think there are deep mysteries left about how the retina converts o visual signals, you light, into inteneral signals. The further toward the centre of the brain you get, the more the more mysterious it becomes. And same is true at the coclia of transducing sound, and in general, at the periphery. You now nerves driving muscles. We know a lot about how that works as well. It's the stuff in between, the interesting stuff that neare.