Acoustically driven thermal-identified neurons in the preoptic area of unanesthetized rabbits.

The convergence of acoustically stimulated neural activity onto central and peripheral thermal-stimulated neurons in the preoptic/anterior hypothalamus (POAH) was studied in the unanesthetized rabbit. POAH single units were either directly thermally stimulated with a water-perfused thermode, or indirectly stimulated by warming the ears with an infrared lamp. There was no statistical distinction in the way central thermal-stimulated neurons responded to an 89 dB, 510 Hz sound pulse. There was a significant interaction in the response of neurons inhibited by skin heating (cold-responsive) to acoustic stimulation with 52% facilitated, 33% inhibited and 15% unaffected. It is possible that some neurons in the POAH are part of a common pathway leading to an activation of thermal- and acoustically-induced changes in motor activity.