Two kinds of intracranial stimulation as counterconditioners of persisting avoidance in rats

Abstract

Rats were fixed with chronically indwelling electrodes to provide intracranial stimulation (ICSl ICS for one group stimulated the medial forebrain bundle and was positively reinforcing. ICS for another group stimulated subcortical areas away from the forebrain bundle and yielded forced movement and no reinforcement. After tests for effects of ICS, rats were trained to avoid footshock by climbing from a grid to a shelf that retracted periodically. After avoidance was established, footshock was terminated and rats were prevented from further responding by removal of the shelf. During three different periods of response prevention, the two kinds of ICS and no ICS were imposed, yielding nine treatments conforming to a 3 by 3 factorial design. After treatment, the shelf again was available and rats' perseveration of avoidance tabulated. Rats receiving positively reinforcing ICS during longer response prevention times responded the least.

Methods of deconditioning persisting avoidance: Drugs as adjuncts to response prevention

“…The procedures of the other studies were very similar to those reported here except for the procedure to interfere with freezing at the beginning of testing. Small doses of amphetamine may lead to some increased movement, which in turn might aid the processes of RP (Hunsicker et al, 1973;Liederhandler & Baum, 1970), but evidently the beneficial effects of amphetamine are relatively dose specific and are limited to rather special testing circumstances. Because freezing is so typical of rats, it is presumed that any beneficial effects of low doses of amphetamine are species specific.…”

“…In our previous studies (e.g., Hunsicker, Nelson, & Reid, 1973), high levels of concordance were found between posttreatment measures, i.e., trials to criteria, "avoidance responses" to criteria (jumps to the ledge within 10 sec), "escapes" to criteria (jumps to the ledge after 10 sec), and latency of the first response. Consequently, we only measured trials to criteria and assumed that trials reflected other potential measures of persisting avoidance.…”

Counterconditioning of memory in rats

“…Consider a typical paradigm in which subjects are given a positive event (e.g., food or rewarding brain stimulation)during a forced exposure to a stimulus that had previously been conditioned to elicit fear. Some studies have found this counterconditioning procedure to be more effective than an extinction exposure (Hunsicker et al, 1973;E. H. Wilson & Dinsmoor, 1970), but others have not (Delprato & Jackson, 1973), and some have even concluded that there is no bona fide counterconditioning process (Capaldi et al, 1983).…”

“…Pairing the aversive CS with the appetitive US is expected to produce greater reductions in fear of the CS than that produced by mere exposures to the CS (i.e., extinction). For example, Hunsicker, Nelson, and Reid (1973) found that rats given rewarding intracranial stimulation during a forced exposure to a previously shocked location exhibited less avoidance of that location on a subsequent test than did subjects given the forced exposure only. As noted by Dearing and Dickinson (1979), most studies of counterconditioning have been of the type in which an aversive CS is presented in conjunction with an appetitive US, and the focus of this study is on issues related to that paradigm.…”

Methods of deconditioning persisting avoidance: Response prevention and counterconditioning after extensive training

“…Cha nging th e affec tive state of th e anim al through the intro duction of a positive affec tive stim ulus duri ng respons e prevention (c ou ntercond itioning) attenua tes per sistent avoida nce even more (Wilson & Davison, 1971 ; Reid , 197 3). Posit ive in tracran ial stimulation (ICS) of th e lat eral hypotha lam us has been used in some of th e studies dem onstrati ng the effective ness o f cou nte rcondit ioning (Buss & Reid , 1973 ; G ordon & Baum , 1971 ;Hunsicker, Nelson , & Reid , 1973 ; Prad o-Alcala, Bush , Steele , & Reid , 197 3).In nearly all lab oratory studies test ing vario us ways t o redu ce persisting avoidance, Ss are tested after o nly minim al training (in th is paradigm, usually after 25 or so tra ining tri als) . Baum (196 8) gave rats eit her 50 or 100 additional trials afte r the avoidance was acquired.…”