These dental patients had just had an impacted wisdom tooth extracted, a procedure which predictably causes postoperative pain for some time. After their local anesthetics had worn off and the period of postoperative pain had started, the patients were given two injections, some hours apart. After this dose of naloxone, the placebo-responders again felt their pain. Yet naloxone does not affect some other kinds of experimental pain. I n pathways that convey sensation from transducers to the brain.
Light touch feels like burning or an electric shock.
This excessive amplification seems to occur when pathways for sensation from the body are damaged in the brain. Less sensation seems to reach the cortex, which may in turn ask the reticular activating system to turn up the amplifier full-blast. This is one possibility for what is wrong with the following patient. It took about three months after her stroke for Edith to regain full function in her paralyzed left hand. Even when it moved well, the hand felt numb, as did the rest of her left side.