Vital signal processing is sustained in a subset of neurons in the nucleus tractus solitarius (NTS) at cold temperatures in the Syrian hamster, a hibernating species, but not in the rat, a nonhibernating species

Crucial for survival, cardio‐respiratory reflexes must continue to reliably process sensory information to ensure that changes in energy demand are matched by supply over hibernation bouts. Here we tested the hypothesis that hamster NTS neurons, unlike those of rats, have adaptations to sustain NTS signal processing at low brain temperatures. Using patch clamp techniques, we classified 2nd‐order NTS neurons in euthermic Syrian hamsters and rats as rapid‐onset (RS) or delayed‐onset (DS) spiking phenotypes based on their spiking‐onset to a depolarizing pulse following a −80 mV pre‐pulse. Tractus solitarius stimulation evoked EPSCs in phenotypes at 15, 25 and 33 °C. At all 3 temperatures, hamster RS neurons had a higher spiking response ( p <0 .05) to step depolarization from a resting potential of −50 mV than did hamster DS, rat DS, and rat RS neurons. Although action potential width increased in all 4 phenotypes as temperature declined, hamster RS neurons also had a significantly shorter duration ( p < 0.05) than did the other 3 phenotypes. In contrast, hamster DS neurons had more negative resting potentials ( p < 0.05) than the other 3 phenotypes. These data support our hypothesis. They also suggest that during hibernation, hamster RS neurons continue to process signals in contrast to the minimally active DS neurons and the latter contribute more to energy conservation than do the RS neurons.