Temperature Sensitivity in the Prothoracic Ganglion of the Cockroach, Periplaneta Americana, and Its Relationship to Thermoregulation

1. Activity of neurones in the prothoracic ganglion of the cockroach, Periplaneta americana, recorded extracellularly, showed a wide range of temperature sensitivity. These responses were categorized by linear regression. 2. The regression lines with the greatest slopes are proposed to characterize central temperature receptors; warm units with lower slopes may be the result of nonspecific Q10 responses of ordinary neurones. 3. An overlap of regression lines from cells with high slopes occurs near the acclimation temperature of the animals; the regression lines of most of the warm-sensitive units reach zero firing rate near the mean chill-coma temperature (10*5 C) for this species. 4. The temperature selection by the whole animal in a temperature gradient shuttlebox was found to require central temperature receptors as well as the peripheral temperature receptors on either the antennae or tarsi. 5. Both neural and behavioural data indicate a greater sensitivity to heat than cold in cockroach thermoregulatory behaviour.