Divergence of conditioned eyeblink and conditioned fear in backward Pavlovian training

Abstract

Two experiments of Pavlovian conditioning with rabbits evaluated the effects of initiating or continuing a conditioned stimulus (CS) after a paraorbital unconditioned stimulus (US). In Experiment 1, backward pairings, in which a CS carne on after the US, produced a CS that appeared inhibitory on a measure of eyeblink conditioning but excitatory on a potentiated-startle measure of conditioned fear. In Experiment 2, extending the duration of a CS that carne on prior to the US,so that it continued after the US, decreased eyeblink conditioned responses, whereas it increased conditioned fear. The data from the two experiments confirm and extend those of Tait and Saladin (1986), supporting the suppositions of AESOP (Wagner & Brandon, 1989) that conditioned eyeblink and conditioned fear can be dissociated under various temporal relationships between the CS and US. Tait and Saladin (1986) reported that "backward" training, where an aversive unconditioned stimulus (US) was followed, rather than preceded, by a conditioned stimulus (CS), produced a CS that appeared concurrently excitatory and inhibitory, depending on the measure of associative learning employed. After 65 conditioning trials, where a 1,000-msec tone CS was administered 500 msec after a 1OO-msec paraorbital shock US, the tone appeared excitatory as indicated by its acquired ability to suppress drinking behavior, whereas it appeared inhibitory as evidenced by its retardation in subsequent acquisition ofeyeblink conditioned responses (CRs). Wagner and Brandon (1989) pointed to these data as providing especially clear evidence that CS-US pairings can produce an association between the CS and the emotive qualities of the US (as presumably reflected in common measures of conditioned fear) that is separable from the association between the CS and the remaining sensory-perceptual attributes ofthe US (as presumably seen in discrete CRs, such as the eyeblink). The separability is such that, under the conditioning parameters employed by Tait and Saladin, one association may be excitatory while the other is inhibitory.The data reported by Tait and Saladin (1986) might have been anticipated on the basis of the separate literatures on fear conditioning and on eyeblink conditioning concerned with the effects of backward US-CS pairings. Studies offear conditioning that have employed relatively short US-CS intervals have repeatedly reported an excitatory associative consequence

Integration of cardiac responses to serial stimuli after Pavlovian conditioning in rats

“…AlthoughAESOP suggests different neural substrates for NMRs (sensory nodes) and longer, fear-related responses (emotional), such as cardiac CR (Lennartz & Weinberger, 1992;McNish, Betts, Brandon, & Wagner, 1997;Vandercar & Schneiderman, 1967), the present results suggest that real-time summation may be observed in both types of responses and on a longer time scale than with the NMR.…”

Backward conditioning: Mediation by the context.

“…LoLordo and Fairless (1985) and Williams, Dyck, and Tait (1988) proposed a cue-competition account, according to which the shift from excitation to inhibition presumably reflects the effectiveness of the context with increasing numbers of trials to compete with the backward-trained CS for controlling excitatory conditioned responding. The present experiments explored the role of context in excitatory and inhibitory 1 Notably, the point of transition from excitation to inhibition with increasing numbers of trials appears to differ as a function of the response being monitored, presumably because different responses reflect associations to somewhat different US attributes (McNish, Betts, Brandon, & Wagner, 1997;Tait & Saladin, 1986). stimulus control produced by backward conditioning. In three conditioned lick-suppression experiments, we explored the mediating role of the training context with respect to the excitatory and inhibitory potentials of a backward-trained CS.…”

Outcome-specific conditioned inhibition in Pavlovian backward conditioning

“…Instead, such research has been concerned with a different aspect of the model-namely, its prediction that with some US-CS intervals, the CS may simultaneously develop excitatory and inhibitory associations with the US. Although it seems reasonably clear from prior research that a backward CS can simultaneously acquire both excitatory and inhibitory properties (e.g., Cole & Miller, 1999;McNish et al, 1997;Tait & Saladin, 1986), the sensory specificity of such learning is less clear.…”

“…However, recently, a considerable amount of interest has been directed to the study of backward Pavlovian conditioning, where the US precedes the CS (e.g., Cole & Miller, 1999;McNish, Betts, Brandon, & Wagner, 1997;Romaniuk & Williams, 2000;Silva & Timberlake, 2000;Silva, Timberlake, & Cevik, 1998;Williams & Hurlburt, 2000). Learning, in this situation, has been described from very different theoretical orientations as being excitatory, inhibitory, or both excitatory and inhibitory.…”