Effect of pentobarbital, chloralose, and urethane on inhibitory postsynaptic potentials of cortical neurons

Convergence of skin and hypothalamic temperature signals on the sulcal prefrontal cortex in the rat

Single unit activities in the sulcal prefrontal cortex (S-PEC) were recorded during thermal stimulation of scrotal skin and the hypothalamus in urethane-anesthetized rats. (1) Of all the 146 S-PFC units tested, 126 (86%) units changed the firing rate in response to changes in scrotal skin temperature (Tsc), and 98 (67%) units to alterations in hypothalamic temperature (Thyp). Sixty-five percent of the S-PFC units responded to both Tsc and Thyp changes. (2) Response characteristics of Tsc-responding S-PFC units were modified when the hypothalamus was warmed or cooled. (3) Microinjection of procaine into the dorsomedial nucleus of the thalamus reversibly blocked the response of S-PFC units to changes in Tsc and/or Thyp. (4) The high degree of convergence of thermal signals from scrotal skin and the hypothalamus on the S-PFC suggests that the S-PFC neurons play a role in processing and integrating thermal signals arising from different parts of the body, probably in connection with the emotional and/or motivational aspect of neural sensation and thermoregulatory behavior.