The conditioning of dyspneic suffocation fear. Effects of carbon dioxide concentration on behavioral freezing and analgesia. Behav Modif

Previous studies in our laboratory have shown that a single exposure to 100 % carbon dioxide (CO2) can serve as an effective unconditioned stimulus (US) in a Pavlovian aversive-context conditioning paradigm in rats. Although the US exposure parameters employed in the initial studies were sufficient for producing a context-specific enhancement of behavioral freezing and analgesia, it had yet to be determined whether variations of these CO2 conditioning procedures would produce other conditioning effects. Thus, the purpose of the following experiment was to investigate the intensity of the US on the conditioned response (CR). The findings confirm that variations inCO2 concentrations produce changes in theCR that are consistentwith principles of Pavlovian conditioning. The findings lend additional support to the tenability of a dyspneic suf-focation fear theory of panic disorder, a theory that postulates that at least one type of panic attack could be a consequence of Pavlovian conditioning