Carbon dioxide escape and avoidance behavior in the brown rat.

Abstract

Rats were restrained in a small chamber through which various gas mixtures could be pumped. Three rats were exposed to concentrations of CO2 of 8%, 10% and 15%. They successfully learned to escape regularly for 30 second periods by touching a metal tube. They were subsequently trained to avoid the onset of air containing similar CO2 concentrations by pressing a panel. The functions relating response measures to concentrations were monotonic but curvilinear. The threshold for escape behavior appeared to be slightly below 8%.