Neuronal activities related to thermoregulation.

The hypothalamic thermoregulatory center was regarded as a black box some 20 years ago. Subsequent microelectrode exploration revealed the existence of two kinds of thermosensitive neurons in this area. Discharges of these neurons are now recorded not only from anesthetized animals but also from tissue explants, tissue slices, and unanesthetized animals as well. Neuronal responses produced by some stimuli have been compared to whole-body thermoregulatory responses. Parallelism between the two was found in the actions of chemicals, in integration of peripheral and central temperatures, in cortical influence, and in temperature effects on other hypothalamic functions, implicating specific key roles to thermosensitive neurons in thermoregulation.