We've been discussing alot of information about the spinal cord, the brain, and the connections between the two that can produce observable behavior. The interesting pieces of the "nervous system puzzle" are those that deal with the abnormalities and phenomenons associated with behavior. The intricate communication between caudal and rostral to the medulla through to the telencephelon may not be observable, but the output it generates is: a behavior, an action, a feeling, a movement, a response.

After reading Phantom Limbs (April, 1992), however, it seems that even without this communication which I thought was essential, an output of some sort may be observable! Parapalegics with complete breaks in the spinal cord have feeling and pain in their limbs despite the block of communication. Similarly, amputees have the sense that their limbs still exist. In fact, they experience pain in non-existent arms and legs, etc.! It is absolutely fascinating.

This raises the whole issue of whether the brain simply processes incoming information and analyzes it accordingly OR whether the brain isn't as pasive as we (or I) had thought. Maybe it generates its own output which is just comlemented, not necessarily dictated, by sensory input. The article propses a whole genetically determined "matrix" which is unique for each individual. It networks the parietal lobe, the limbic system, and the sensory pathway. These incorporate the sensory stimulation, a sense of self, and a generation of impulses to reassure the body is one whole. The output from the matrix carries information about the sensory input, but it also gives validity that the sensation is indeed occuring.

So without any true input from a limb, since the limb isn't even there, the rest of the body perceives pain, other sensation, and most importantly (and strangely!!), it feels like the limb is actually still attached. The idea that the brain generates this without any input makes me wonder. Maybe humans really aren't simply machines which react to input and act because of random nerve firings. This hypothesis reworks that idea in that the brain itself is "in control". Although genetically programmed, the matrix functions autonomously sometimes with, sometimes without, external or real stimulation.

To move into stream of consciousness, this certainly brings my thoughts back to the possibility of mind, soul, and a being. If our brains can make us believe we have body parts that really aren't there, they may be more complex than networks of nerves.

You're ahead of us, but that's fine. Yes, indeed, a sense of limb location may exist in absence of any input from the limb. Part of why we're not there yet is that we need some things first to understand how that could happen with no mystery, simply as a consequence of "networks of nerves". So we'll come back to the issue in a bit. Meanwhile, though, your more general point is entirely appropriate: the nervous system (as we'll see again and again) is NOT a passive receiver of and reactor to sensory information. PG