Drug effects on signaling

Bar graph: two bars, warm-hand condition 195 ms and cold-hand condition 248 ms, y-axis labeled "Reflex latency (ms)," x-axis labeled "Hand temperature."\n\nClaim: Cooling the skin and nerves of the hand would lengthen the withdrawal-reflex latency compared to a warm hand.\n\nEvidence: In our data, the average time from touch to finger pull-back rose from 195 ms with a warm hand to 248 ms with a cold hand, a slowdown of about 53 ms.\n\nReasoning: A reflex signal has to travel along sensory and motor neurons and cross synapses, and anything that slows that pathway lengthens the measured latency. Cooling does this physically, because lower temperature slows the ion movement and membrane processes that drive each action potential, so the impulse travels more slowly down the axon. That is why cooling by a few degrees added about 53 ms to the reflex, the same direction that any change slowing conduction would push. Warming the pathway would do the opposite, speeding conduction and shortening the latency back toward or below the warm baseline.