Even after rereading the analgesia chapter in Kandel, I'm having trouble
understanding the mechanism in which the sensation of pain can be
experienced in areas where there's no other sensory activity. For instance,
if a peripheral nerve is severed and a limb or digit then becomes numb to
all forms of sensory activity, how then can pain still be detected in these
areas?
More specifically, about 2 weeks ago I was in an accident where I sustained
a rather deep laceration in the upper wrist / lower hand resulting in the
ulnar nerve becoming severed, as well as part of the median nerve (and a
tendon and artery, which were also repaired). The nerves were reattached,
but theres no feeling (proprioreceptive or cutaneous) in 3 fingers and parts
of the upper palm. However, there's the sensation of "shooting pain" at the
fingertips and elsewhere in these areas. How is that possible? Could it be
a result of feedback with adjacent nerves in the relay sites and cns? What
about distal portions of the nerve beginning to regain function but not yet
being "remapped" after reattachment? As you can see, I have no ideas.
Kandel's book touches on this sort of phenomenon, but nothing specific
enough to answer this type of question.
Any insights are appreciated.
- Mark Zarella
