Thermosensitive neurons in the brain.

Since the discovery of thermosensitive neurons in the POAH, numerous papers have been published suggesting the primary importance of these neurons in thermoregulation. The basic properties of the neurons per se were well studied in cultured explants and slice preparations, outside of the influences of anesthesia and extrahypothalamic inputs. Attempts have been made to classify thermosensitive neurons according to firing rate and response pattern and to correlate each neuron group with thermoregulatory responses. In complex thermoregulatory networks, thermosensitive neurons are always under the influences of extrahypothalamic and non-thermal inputs. Most studies on POAH neurons have shown a variety of responses, some contrary to others; for instance, three-fourths of POAH warm-sensitive neurons may be facilitated by scrotal warming whereas the rest are inhibited or uninfluenced. These inconsistencies in responses among thermosensitive neurons, observed also in the effects of chemicals, may reflect different roles of POAH thermosensitive neurons in a variety of thermoregulatory responses. Unit recordings from conscious animals over long periods, together with observation on whole body responses, are expected to throw more light on the physiological significance of POAH thermosensitive neurons.