Generally I find the subject of paralysis and the interactions of spinal cord and brain extremely interesting. I had a personal experience of paralysis that was drug induced.

In order to have joint replacement surgeries I opted for an epidural. This procedure stops sensory feeling and motor functions from about the waist down by inserting a catheter directly into the spinal fluid by which passes such drugs of the opiate variety. Somehow, because the interaction occurs in the spinal cord, only (or mostly) my legs were involved. One of the side effects that I noticed was that for months (years) afterward I did not have complete feeling in my toes. Instead I would have a zinging or tingly sensation which was not painful but yet worse because it was "half" of a sensation. To this day I do not have complete restoration of feeling in my toes.

Since then, I wondered how the medications worked on the nerve cells and whether some sort of leftover sensation was the cause of strange sensory information felt months after the numbing effects of the epidural wore off. Also, what kind of imbalance was caused inside the entire spinal column because of the foreign chemicals?

In talking with my doctors I never got the feeling that they had complete understanding of why epidurals work. In fact, after being on an epidural for seven days I experienced an overdose (due to miscalculations) and as a result had two epileptic seizures. The fact that I had never had seizures before and that the doctors realized their error, pretty much indicated that the drugs in my spinal fluid interacted with my brain, as well, to cause an electrical imbalance. This means that the drugs were not only effecting my legs but were effecting my brain and probably circulating throughout my blood as well. But why, then, did not my whole body experience numbness?

There are so many more questions about how the spinal cord and brain and body interact. I am at a loss as to try to explain all that I experienced, such as a seven day memory loss after my seizures, but I might suggest that signals are possibly saved someplace in the body and resurface in a translated form. And could it be the case that spinal fluid carries its own form of communication to the brain, without the involvement of neurons, that is chemical in nature and could have caused my seizures? This is something I continue to think about.

Very much worth continuing to think about. Many thanks for the personal observations. Obviously, the intent of the epidural is to locally inactivate sensory pathways (taking advantage of the fact that they come into the nervous system at different locations, as we talked about in class). Equally obviously, as you say from your experiences, there was unintended broadening of the effects, both in space and in time. And, as you say, it was probably not general drug circulation, since you didn't have whole body numbness. Lots to think about (and yet to be understood), but yes, spinal fluid is continous with fluids bathing brain and can be a communication pathway independent of neurons (would bet though that there is neural communication involvement in symptoms you describe). PG