Mario A. Laborda

Extinction context as a conditioned inhibitor

Two lick suppression experiments using rats were conducted to determine whether extinction of a punctate excitor in a particular context would result in that context becoming a conditioned inhibitor, as defined by passing both summation and retardation tests. The role of extinction trial spacing was investigated as a possible determinant of whether the extinction context would become inhibitory. Experiment 1 demonstrated that, although inhibition was evident using either massed or spaced extinction trials, spaced trials reduced measurable inhibition as assessed by the summation test, but trial spacing had no influence on retardation test performance. Experiment 2 confirmed Experiment 1’s conclusions while controlling for the influence of latent inhibition on the retardation test. In Experiment 2, the context proved inhibitory only following massed extinction trials. These data suggest that, at least with select parameters, an extinction context can become inhibitory.

Contrasting AAC and ABC renewal: the role of context associations

Rats were used in a lick suppression preparation to assess the contribution of conditioned-stimulus (CS)–context and context–unconditioned-stimulus (US) associations to experimental extinction. Experiment 1 investigated whether strengthening the CS–acquisition context association enhances extinction by determining whether stronger extinction is observed when CS-alone trials (i.e., extinction treatment) are administered in the acquisition context (AAC renewal), relative to a context that is neutral with respect to the US (ABC renewal). Less recovery of responding to the CS was observed in the former than in the latter case, extending the finding that AAC renewal is weaker than ABC renewal to our lick suppression preparation. Experiment 2 assessed the contribution of the acquisition context–US association to extinction of a CS by examining the effect of postextinction exposure to the acquisition context on responding to the extinguished CS. This manipulation enhanced responding to the extinguished CS in AAC, but not ABC, renewal. Experiment 3 addressed the contribution of the CS–acquisition context association by examining the potential of a neutral stimulus, presented in compound with the target CS during extinction treatment, to overshadow the CS–acquisition context association. This manipulation enhanced responding to the extinguished CS in AAC, but not ABC, renewal. The results stress the important role of contextual association in extinction and renewal.

Preventing Recovery From Extinction and Relapse A Product of Current Retrieval Cues and Memory Strengths

When a cue (X) and an outcome are paired, X comes to elicit responding similar to that elicited by the outcome. This potential is lessened if X is later presented by itself (i.e., experimental extinction). Extinction is interesting both for theoretical reasons and because it is a model for exposure therapy, which is used to treat numerous psychological disorders. Conventionally, extinction has been viewed as an isolated phenomenon unrelated to other response-attenuating treatments, whereas it is actually but one of several instances of associative interference that reduce conditioned responding. Although much has been learned about extinction from direct study, the larger associative-interference literature provides additional insight. Here we view extinction as new learning that is inconsistent with previously acquired knowledge (i.e., retroactive outcome interference). We provide an account of whether the acquisition or extinction memory will be expressed depending on the relative strengths of these two memories and the relative efficacies of their respective retrieval cues.

Preventing Return of Fear in an Animal Model of Anxiety: Additive Effects of Massive Extinction and Extinction in Multiple Contexts

Fear conditioning and experimental extinction have been presented as models of anxiety disorders and exposure therapy, respectively. Moreover, the return of fear serves as a model of relapse after exposure therapy. Here we present two experiments, with rats as subjects in a lick suppression preparation, in which we assessed the additive effects of two different treatments to attenuate the return of fear. First, we evaluated whether two phenomena known to generate return of fear (i.e., spontaneous recovery and renewal) summate to produce a stronger reappearance of extinguished fear. At test, rats evaluated outside the extinction context following a long delay after extinction (i.e., a delayed context shift) exhibited greater return of extinguished fear than rats evaluated outside the extinction context alone, but return of extinguished fear following a delayed context shift did not significantly differ from the return of fear elicited in rats tested following a long delay after extinction alone. Additionally, extinction in multiple contexts and a massive extinction treatment each attenuated the strong return of fear produced by a delayed context shift. Moreover, the conjoint action of these treatments was significantly more successful in preventing the reappearance of extinguished fear, suggesting that extensive cue exposure administered in several different therapeutic settings has the potential to reduce relapse after therapy for anxiety disorders, more than either manipulation alone.

Classical conditioning and pain: Conditioned analgesia and hyperalgesia

This article reviews situations in which stimuli produce an increase or a decrease in nociceptive responses through basic associative processes and provides an associative account of such changes. Specifically, the literature suggests that cues associated with stress can produce conditioned analgesia or conditioned hyperalgesia, depending on the properties of the conditioned stimulus (e.g., contextual cues and audiovisual cues vs. gustatory and olfactory cues, respectively) and the proprieties of the unconditioned stimulus (e.g., appetitive, aversive, or analgesic, respectively). When such cues are associated with reducers of exogenous pain (e.g., opiates), they typically increase sensitivity to pain. Overall, the evidence concerning conditioned stress-induced analgesia, conditioned hyperalagesia, conditioned tolerance to morphine, and conditioned reduction of morphine analgesia suggests that selective associations between stimuli underlie changes in pain sensitivity.

Reactivated memories compete for expression after Pavlovian extinction

We view the response decrement resulting from extinction treatment as an interference effect, in which the reactivated memory from acquisition competes with the reactivated memory from extinction for behavioral expression. For each of these memories, reactivation is proportional to both the strength of the stimulus-outcome association and the quality of the facilitatory cues for that association which are present at test. Here we review basic extinction and recovery-from-extinction phenomena, showing how these effects are explicable in this associative interference framework. Moreover, this orientation has and continues to dictate efficient manipulations for minimizing recovery from extinction. This in turn suggests procedures that might reduce relapse from exposure therapy for a number of psychological disorders. Some of these manipulations enhance the facilitatory cues from extinction that are present at test, others strengthen the extinction association (i.e., CS-no outcome), and yet others seem to work by a combination of these two processes.

On the differences in degree of renewal produced by the different renewal designs.

This paper addresses sources contributing to the differences in the degree of recovery from extinction observed with different renewal paradigms. In two lick suppression experiments with rats, we assessed the role of the associative status of the acquisition context in both the weakness of AAC renewal and the sometimes observed weaker renewal resulting from an ABC design relative to an ABA design. In Experiment 1, we observed that AAC renewal relative to an AAA control group was small unless Context A had undergone associative deflation (i.e., extinction of Context A). Deflation of Context A not only decreased behavioral control by the CS in the AAA condition, but increased it in the AAC condition, thereby implicating a comparator process in addition to associative summation between the CS and test context. In Experiment 2, an excitatory acquisition context was found to enhance the difference between ABC and ABA renewal. Associative deflation of the acquisition context decreased ABA renewal more than ABC renewal. Thus, the associative value of the acquisition context (A) was more positively related to the level of renewal when the target CS (X) was tested in this context than when it was tested in a neutral but equally familiar context (C), consistent with the frequently observed greater renewal in an ABA condition than an ABC condition arising from associative summation of the CS and test context. These findings demonstrate that the excitatory status of the acquisition context influences the observed degree of renewal.

S-R Associations, Their Extinction, and Recovery in an Animal Model of Anxiety: A New Associative Account of Phobias Without Recall of Original Trauma☆

Associative accounts of the etiology of phobias have been criticized because of numerous cases of phobias in which the client does not remember a relevant traumatic event (i.e., Pavlovian conditioning trial), instructions, or vicarious experience with the phobic object. In three lick suppression experiments with rats as subjects, we modeled an associative account of such fears. Experiment 1 assessed stimulus-response (S-R) associations in first-order fear conditioning. After behaviorally complete devaluation of the unconditioned stimulus, the target stimulus still produced strong conditioned responses, suggesting that an S-R association had been formed and that this association was not significantly affected when the outcome was devalued through unsignaled presentations of the unconditioned stimulus. Experiments 2 and 3 examined extinction and recovery of S-R associations. Experiment 2 showed that extinguished S-R associations returned when testing occurred outside of the extinction context (i.e., renewal) and Experiment 3 found that a long delay between extinction and testing also produced a return of the extinguished S-R associations (i.e., spontaneous recovery). These experiments suggest that fears for which people cannot recall a cause are explicable in an associative framework, and indicate that those fears are susceptible to relapse after extinction treatment just like stimulus-outcome (S-O) associations.

Trial spacing during extinction: the role of context-US associations.

Studies of extinction in Pavlovian preparations can identify conditions that make extinction more enduring and increase the benefits of exposure-based behavior therapy. One such potential condition is the use of spaced extinction trials. Nevertheless, contradictory results of spacing extinction trials are found in the existing literature. Here we examine the strength of the association between the extinction context and the unconditioned stimulus as a variable that reconciles the seemingly contradictory prior reports. To assess the role of this variable, we evaluated the effects of extinction trial spacing as a function of the associative status of the extinction context in three lick suppression experiments with rats. In Experiment 1, the associative status of the extinction context was manipulated by giving extinction treatment in either the same context as acquisition or a different context. In Experiment 2, the associative status of the extinction context was initially high as a result of the acquisition context being used for extinction and then it was manipulated through postacquisition context exposure. In Experiment 3, extinction was administered in a context different from that of acquisition and the associative status of the extinction context was manipulated by delivering unsignaled footshock (i.e., the unconditioned stimuli) in the extinction context between acquisition and extinction. In all three experiments, consistently less conditioned suppression was observed with spaced extinction trials relative to massed extinction trials when the associative value of the extinction context was relatively low. In contrast, massed extinction trials produced less conditioned suppression when the associative status of the extinction context was high. Thus, stimulus control after extinction is influenced by an interaction between the intertrial interval during extinction and the associative status of the extinction context.

Animal models of psychopathology: Historical models and the pavlovian contribution

La investigacion con animales no humanos como sujetos experimentales, para entender el comportamiento humano, se basa en la nocion darwiniana de la continuidad de las especies. En este marco encontramos modelos analogos para entender la biologia y el comportamiento humanos en especies no humanas. En psicologia, los modelos animales han probado ser una herramienta efectiva para el entendimiento del comportamiento humano, tanto normal como anormal. En la presente revision discutimos como los modelos animales han sido usados al investigar la psicopatologia. Luego de revisar tres modelos animales historicos de psicopatologias especificas, discutimos como los fenomenos descubiertos al estudiar el condicionamiento pavloviano han contribuido a nuestra comprension de la etiologia y mantencion de la psicopatologia humana, como la tradicion pavloviana ha contribuido al desarrollo de mejores formas de tratamiento para desordenes del comportamiento, y de forma mas general, como los fenomenos pavlovianos se encuentran implicados en casi todas las interacciones entre un organismo y su ambiente.