Thermosensitive neurons in slice preparations of rat medulla oblongata

With extracellular recording, we examined thermosensitive neurons in slices of a possible thermosensitive region in the dorsal medulla oblongata of rats. In addition to temperature insensitive neurons, warm- and cold-sensitive neurons were recorded in vitro. The firing rates of many warm- and cold-sensitive neurons responded transiently to temporal changes in slice temperature with "overshoots" and/or "reverse overshoots." In a steady state, warm-sensitive neurons were similar in thermoresponsiveness to those studied previously in the CNS in vivo. Cold-sensitive neurons were unique in that. Most of them were silent at the normal core temperature of 38 degrees C and fired only below their own threshold temperatures (2-6 degrees C below normal).