One of the first things that most designers forget about CSS descendant selectors is that they are flexible. When CSS defines a descendant, it doesn't care whether the tag in question is the direct child, the grandchild, or some great-great-great-descendant of the initial element.
From the retina, visual information passes onto the bipolar cells and then to the optic nerve's ganglion cells. The optic nerve, which begins at the retina, is the sole visual pathway to the brain. Light information is conveyed as an electrical action potential through the neurons.
What isn't controversial is that the function of a neuron is to receive INPUT information from other neurons, to process that information, then to send information as OUTPUT to other neurons. (Synapses are connections between neurons through which information flows from one neuron to another.) Hence, neurons process all of the information that flows within, to, or out of the CNS. All of it!