Effects of rewarding, aversive, and neutral intracranial stimulation administered during flooding (response prevention) in rats

Abstract

Flooding or response prevention consisted of blocking the learned avoidance response while forcing the animal to stay in the presence of the feared object. The present study investigated the effects of rewarding (in the anterior lateral hypothalamus), aversive (in the dorsomedial tegmentum), and neutral forced intracranial stimulation (ICS) of anterior brain structures during flooding in rats. No effect on avoidance extinction was produced by any type of ICS, while a significant increase of freezing behavior was found during flooding in Ss receiving aversive ICS. These results were discussed in relation to our previous study, which showed that rewarding (in the posterior lateral hypothalamus) and aversive (in the reticularis pontis caudalis) ICS of posterior areas during flooding produced a significant decrease and a tendency to increase avoidance behavior, respectively. It was suggested that the stimulation of posterior areas was more reinforcing (positively and negatively) than the stimulation of anterior structures.

Extinction of avoidance responding in rats: The noise-intensity parameter in noise-facilitation of flooding.

“…Flooding (response prevention) generally facilitates avoidance extinction (see Baum, 1970, Baum, 1976 for reviews). However, under conditions where shock is intense during acquisition (e.g., 1.3 mA for the rat) and the duration of flooding is relatively short (e.g., 3 or 5 minutes total exposure time to the evocative stimulus), the efficacy of unassisted flooding in hastening subsequent avoidance extinction is limited and the procedure has little effect (Baum, 1969; Baum, Leclerc, & St. Laurent, 1973; Baum, Roy, & Leclerc, 1985; Leclerc, St. Laurent, & Baum, 1973). Under such circumstances, flooding efficacy can be enhanced by the continuous sounding of a loud buzzer during the flooding period (Baum & Gordon, 1970).…”