kaim at pi.net wrote:
: I mean with my friend there is still an optical nerve. It's his eye
: that doen't work anymore.
: Is this a stupid idea, or is it simply too dificult to do ?
A lot depends on why his eye (retina) doesn't work. The fibers of the
optic nerve are axons of ganglion cells in the retina. If these cells
are non-functional or dead, it is likely that the ooptic nerve fibers are
as well. If so, there is no access to the brain via this route.
: What I'd like to know is how do the optic nerve cells pick up signals, and
: how do "bio sensors" in genaral work.
The cells which you are speaking of are stimulated by electrochemical
events and not by light, directly. The impact of light is on specialized
photoreceptor cells which communicate with the ganglion cells through an
intervening network. The dynamic response properties of the ganglion
cells and the optic nerve fibers is not just a simple indication of light
intensity at a locus but contains already deciphered parameters relating
to position, direction, hue, etc.
Kal
