CORRELATIONS OF TEMPERATURE SENSITIVITY IN MAN AND MONKEY, A FIRST APPROXIMATION

Publisher Summary This chapter discusses correlations that appear reasonable between human thermal sensations and neural activity in the thermal primary afferents of rhesus monkeys. Thermal sensations, measured in humans, and the responses of primary warm and cold fibers, measured in monkeys, are compared to identify possible neural codes. The low levels of neural activity in warm and cold fibers at the static temperatures in the zone of physiological zero, identified in humans, need not necessarily lead to thermal sensations. An increase in the frequency of this activity in warm fibers may account for the persisting warm sensations at higher adapting temperatures. A combination of a temporal code (bursting) and the frequency code in cold fibers can account for the persisting cold sensation and thermoregulatory responses observed at low skin temperatures. A complete adaptation of sensation to a temperature change within the zone of physiological zero requires much more time than the establishment of a new steady-state response in primate warm and cold fibers following a similar change.