Disruption in Pavlovian-Instrumental Transfer as a Function of Depression and Anxiety

The Pavlovian-Instrumental Transfer (PIT) paradigm examines probabilistic and reinforcement learning. Disruptions in mechanisms that mediate PIT (i.e., cues not triggering adaptive behaviors) are thought to be contributors to psychopathology, making the study of probabilistic and reinforcement learning clinically relevant. The current study evaluated an appetitive PIT effect and its relationship with symptom dimensions spanning depression and anxiety, with a particular focus on anhedonia. Forty young adults ranging in scores across dimensions of depression and anxiety symptoms completed the PIT paradigm and self-report symptom measures. The PIT paradigm consisted of three phases. The instrumental phase consisted of a contingent association in which participants squeezed a handgrip for monetary reward. The Pavlovian phase established a purely predictive association between three visual stimuli (CS?+?, CS-, baseline) and presence or absence of monetary reward. In the transfer phase, participants’ responses allowed for examination of whether motivational characteristics of Pavlovian predictors influenced the vigor of their handgrip squeezes (instrumental action), which were formerly independent of Pavlovian associations. Analyses revealed a baseline-reward PIT effect, whereby a reward-associated Pavlovian cue enhanced instrumental responding in the transfer phase. However, there were no significant differences between CS?+?and CS- or CS- and baseline cues, suggesting a disrupted interaction of Pavlovian and instrumental learning. Further, the appetitive PIT effect captured in this paradigm was not associated with anhedonia, fears, or general distress. Future work should investigate the influence of mood states using more specific appetitive PIT paradigms to further understanding of the implications of disrupted reflexive and instrumental responding.

     

Outcome-specific transfer between predictive and instrumental learning is unaffected by extinction but reversed by counterconditioning in human participants

Three experiments were conducted to explore the effects of different interference treatments upon outcome-specific transfer from predictive learning to instrumental responding. A computer game was designed in which participants had to defend Andalusia from navy and air-force attacks. Participants learned the relationship between two instrumental responses (two keys in a standard keyboard) and two different outcomes (destruction of the ships or destruction of the planes). Then, they learned to predict which of two different cues predicted either outcome. Finally, participants were allowed to give either of the two instrumental responses in the presence of each cue. Outcome-specific transfer was shown as a preference for the response that shared the outcome with the current cue. Extinction of the cue before the transfer test had no effect upon transfer, regardless of the level of extinction (Experiments 1-3). However, pairing the cue with the alternative outcome (counterconditioning) reversed the outcome-based transfer effect (Experiment 3). The implications of these results for the contents of extinction in human predictive learning are discussed.     

Trait Anxiety and Fear Responses to Safety Cues: Stimulus Generalization or Sensitization?

Abnormal fear responding to threat cues may contribute to the aetiology and maintenance of persistent fears and pathological anxiety. Chronic anxiety may also involve abnormal fear responding to ??safety?? cues, which do not signal danger. Yet investigations of fear responding to acquired safety cues are scarce and the basis of such responding remains unclear. Moreover, previous studies do not distinguish between stimulus generalization (an associative mechanism based on perceptual similarity between threat and safety cues) and sensitization (a non-associative mechanism whereby fear responses to any novel, intense, or fear-related stimulus are temporarily elevated). This study investigated responses to acquired safety cues in volunteers with varying trait anxiety, using a novel fear conditioning paradigm designed to distinguish between effects of trait anxiety on generalization and sensitization. The paradigm used three conditioned stimuli: a threat cue (CS+) and two safety cues (CS?), one perceptually similar to the CS+ and one perceptually dissimilar. Conditioned fear to these cues was indexed by fear potentiation of the startle blink reflex, skin conductance responses, and self-report. To examine how trait anxiety moderated responses to safety cues, participants were divided into high and low trait anxiety subgroups. Startle, skin conductance, and self-reported fear measures indicated that generalization of fear occurred for the safety cue which resembled the threat cue, but not for the perceptually dissimilar safety cue, consistent with the stimulus generalization hypothesis. There was some evidence that stimulus generalization was exaggerated in anxious individuals. The current study sheds light on the mechanism by which fear responses to safety cues arise in healthy individuals, and offers some insight into the influence of this mechanism in chronic anxiety.     

Pavlovian to instrumental transfer of control in a human learning task

Pavlovian learning tasks have been widely used as tools to understand basic cognitive and emotional processes in humans. The present studies investigated one particular task, Pavlovian-to-instrumental transfer (PIT), with human participants in an effort to examine potential cognitive and emotional effects of Pavlovian cues upon instrumentally trained performance. In two experiments, subjects first learned two separate instrumental response-outcome relationships (i.e., R1-O1 and R2-O2) and then were exposed to various stimulus-outcome relationships (i.e., S1-O1, S2-O2, S3-O3, and S4-) before the effects of the Pavlovian stimuli on instrumental responding were assessed during a non-reinforced test. In Experiment 1, instrumental responding was established using a positive-reinforcement procedure, whereas in Experiment 2, a quasi-avoidance learning task was used. In both cases, the Pavlovian stimuli exerted selective control over instrumental responding, whereby S1 and S2 selectively elevated the instrumental response with which it shared an outcome. In addition, in Experiment 2, S3 exerted a nonselective transfer of control effect, whereby both responses were elevated over baseline levels. These data identify two ways, one specific and one general, in which Pavlovian processes can exert control over instrumental responding in human learning paradigms, suggesting that this method may serve as a useful tool in the study of basic cognitive and emotional processes in human learning.     

Backward blocking: The role of within-compound associations and interference between cues trained apart

Most theoretical accounts of backward blocking place heavy stress on the necessity of the target cue having been trained in compound with the competing cue to produce a decrement in responding. Yet, other evidence suggests that a similar reduction in responding to the target cue can be observed when the outcome is later paired with a novel cue never trained in compound with the target cue (interference between cues trained apart). The present experiment shows that pairing another nonassociated cue with the same outcome may be sufficient to produce a decremental effect on the target cue, but the presence of a within-compound association between the target and the competing cue adds to this effect. Thus, both interference between cues trained apart and within-compound associations independently contribute to backward blocking.     

Backward blocking: the role of within-compound associations and interference between cues trained apart

Most theoretical accounts of backward blocking place heavy stress on the necessity of the target cue having been trained in compound with the competing cue to produce a decrement in responding. Yet, other evidence suggests that a similar reduction in responding to the target cue can be observed when the outcome is later paired with a novel cue never trained in compound with the target cue (interference between cues trained apart). The present experiment shows that pairing another nonassociated cue with the same outcome may be sufficient to produce a decremental effect on the target cue, but the presence of a within-compound association between the target and the competing cue adds to this effect. Thus, both interference between cues trained apart and within-compound associations independently contribute to backward blocking.     

The Influence of Cue Reliability and Cue Representation on Spatial Reorientation in Young Children

Previous studies of children's reorientation have focused on cue representation (e.g., whether cues are geometric) as a predictor of performance but have not addressed cue reliability (the regularity of the relation between a given cue and an outcome) as a predictor of performance. Here we address both factors within the same series of experiments. We show that for 18- to 30-month-olds, high cue reliability is a dominant factor positively affecting reorientation behavior. Under conditions of high cue reliability, children use both scalar and nonscalar cues for successful reorientation. By contrast, under conditions of low cue reliability, children successfully use scalar cues but not nonscalar cues, suggesting that mapping of left–right visual features onto a viewer-centric sense of left and right is facilitated when features themselves are ordered. More generally, we suggest that cue-driven spatial reorientation is best understood as part of a broader system capable of flexibly linking stimuli and responses.     

Reward prospect interacts with trial-by-trial preparation for potential distraction

When attending for impending visual stimuli, cognitive systems prepare to identify relevant information while ignoring irrelevant, potentially distracting input. Recent work showed that a supramodal distracter-filtering mechanism is invoked in blocked designs involving expectation of possible distracter stimuli, although this entails a cost (distraction-filtering cost) on speeded performance when distracters are expected but not presented. Here we used an arrow-flanker task to study whether an analogous cost, potentially reflecting the recruitment of a specific distraction-filtering mechanism, occurs dynamically when potential distraction is cued trial-to-trial (cued distracter-expectation cost). In order to promote the maximal utilization of cue information by participants, in some experimental conditions the cue also signalled the possibility of earning a monetary reward for fast and accurate performance. This design also allowed us to investigate the interplay between anticipation for distracters and anticipation of reward, which is known to engender attentional preparation. Only in reward contexts did participants show a cued distracter-expectation cost, which was larger with higher reward prospect and when anticipation for both distracters and reward were manipulated trial-to-trial. Thus, these results indicate that reward prospect interacts with the distracter expectation during trial-by-trial preparatory processes for potential distraction. These findings highlight how reward guides cue-driven attentional preparation.     

Roles of nucleus accumbens and basolateral amygdala in autoshaped lever pressing

Initially-neutral cues paired with rewards are thought to acquire motivational significance, as if the incentive motivational value of the reward is transferred to the cue. Such cues may serve as secondary reinforcers to establish new learning, modulate the performance of instrumental action (Pavlovian-instrumental transfer, PIT), and be the targets of approach and other cue-directed behaviors. Here we examined the effects of lesions of the ventral striatal nucleus accumbens (ACb) and the basolateral amygdala (BLA) on the acquisition of discriminative autoshaped lever-pressing in rats. Insertion of one lever into the experimental chamber was reinforced by sucrose delivery, but insertion of another lever was not reinforced. Although sucrose was delivered independently of the rats' behavior, sham-lesioned rats rapidly came to press the reinforced but not the nonreinforced lever. Bilateral ACb lesions impaired the initial acquisition of sign-tracking but not its terminal levels. In contrast, BLA lesions produced substantial deficits in terminal levels of sign-tracking. Furthermore, whereas ACb lesions primarily affected the probability of lever press responses, BLA lesions mostly affected the rate of responding once it occurred. Finally, disconnection lesions that disrupted communication between ACb and BLA produced both sets of deficits. We suggest that ACb is important for initial acquisition of consummatory-like responses that incorporate hedonic aspects of the reward, while BLA serves to enhance such incentive salience once it is acquired.     

阈下奖励调节认知控制的权衡

本研究采用奖励版的AX-CPT任务, 通过控制奖励线索和反馈的呈现方式, 设置出基线、阈上奖励、阈下奖励三种条件, 考察习得的奖励联结和奖励动机能否以潜意识的方式影响认知任务的表现和认知控制的权衡。结果显示：奖励线索只在阈上呈现时提高AX序列的任务表现; 与基线条件相比, 阈上和阈下奖励条件下认知控制的权衡均偏向主动性控制, 且这种偏向在两者间无显著差异。这表明习得的阈下奖励线索可以调节认知控制的权衡, 使被试像阈上奖励时那样偏向主动性控制。     

Toxicosis affects instrumental behaviour in rats

Three experiments examined the effect of toxicosis on instrumental responding. These studies were prompted by Morrison and Collyer's (1974, Experiment 1) finding that the induction of toxicosis after an instrumental conditioning session produces greater response suppression if the response is reinforced by a novel saccharin solution rather than familiar water during conditioning. Experiments 1 and 2 investigated whether this suppression was mediated by the Pavlovian contingency between the contextual cues and the saccharin solution or the instrumental relationship between the response and the reward. A role for the instrumental contingency was indicated by the greater suppression of the response producing novel saccharin rather than water when the context of both responses was equally associated with the saccharin and illness. Experiment 3 found that extinction of the aversion to a novel reinforcer following aversive conditioning would re-establish an action previously associated with that reinforcer, in contrast to an action whose reinforcer remained aversive. This result was a further indication that the instrumental contingency between the response and reward contributes to response suppression.     

Memories and anticipations control responding by rats (<Emphasis Type="Italic">Rattus norvegicus</Emphasis>) in a Pavlovian procedure

In Experiment 1 each rat received two different fixed series of three trials each. The unconditioned stimulus occurred on Trial 1 of one series and on Trial 3 of the other series, all other trials being nonreinforced. Previous Pavlovian investigations have shown that rats can remember the immediately prior reward outcome and anticipate the immediately subsequent reward outcome. Experiment 1 demonstrated that rats could remember and anticipate even more remote reward outcomes. In Experiment 2 two groups received a series of two nonrewarded trials followed by a rewarded trial. It was demonstrated that a change in the conditioned stimulus (CS) from Trial 2 to Trial 3, which occurred in one group, produced weaker responding than in the other group that did not experience such CS change. On the basis of these findings it was suggested that the rats organized the trials of a series into a unit or chunk. This was concluded for two reasons. First, remembering and anticipating remote reward outcomes strongly suggests that responding is being controlled by events extending beyond the current trial. Secondly, the experimental manipulations employed in the Pavlovian situation here are similar to those used in prior human learning and animal instrumental learning investigations concerned with chunking. Thus, it would appear that chunking is a ubiquitous phenomenon appearing in human serial learning (e.g., Bower and Winzenz 1969; Crowder 1976), in animal instrumental learning (e.g., Capaldi 1992; Hulse and Dorsky 1977; Terrace 1987), and now in Pavlovian learning.     

Cues produced by reward and nonreward and temporal cues influence responding in the intertrial interval and to the conditioned stimulus

Rats in a Pavlovian situation were trained under three different reward schedules, at either a 30 s or a 90 s intertrial interval (ITI): Consistent reward (C), 50% irregular reward (I), and single alternation of reward and nonrewarded trials (SA). Activity was recorded to the conditioned stimulus (CS) and in all 10 s bins in each ITI except the first 10 s bin. Responding increased progressively over the bins of the 90 s ITI indicating a role for temporal cues in the ITI. Single alternation patterning (SAP), more vigorous responding on rewarded than on nonrewarded trials, occurred in the ITI as well as to the CS and differed little at the 30 s and 90 s ITI. The occurrence of SAP to the CS and, as shown here for the first time, in the ITI along with the findings for the C and I schedules, indicate three matters of importance. First, along with other cues such as temporal cues, behavior is influenced by cues associated with reward and nonreward both in the ITI and when the CS is presented. Second, as the percentage of reward associated with these cues increases so too does vigor of responding. Finally, if the cues produced by reward events are memories the retrieval cues for such memories are present in the ITI as well as when the CS is presented. Considerations are advanced indicating that reward produced cues may influence responding in the Pavlovian situation not only under regular schedules such as the SA schedule, but under all schedules. Indeed, such cues may more validly signal reward and nonreward than the CS itself.     

The effect of informational stimuli on instrumental response rate: Signalling reward versus signalling the availability of reward

Rats were trained to press a lever for food on an interval schedule and were given a brief cue (0.5 sec) between the operative response and the reward (C condition). Some control subjects in Experiments 1, 2 and 4 were given their cue either following the end of the temporal interval during which reward had been unavailable (SD condition), or randomly with respect to food (R condition). Other control subjects in Experiments 2 and 4 received both the food-correlated cue and the temporal-interval stimulus (B condition). In all experiments, rate of responding was lowest for the C subjects and for B animals when the two cues were from different modalities. Food-correlated and temporal-interval cues did not interact, suggesting that a reward-correlated signal does not affect response rate simply by enhancing the salience of the temporal interval offset.     

Personality modulation of (un)conscious processing: Novelty Seeking and performance following supraliminal and subliminal reward cues

This study provides evidence that personality traits associated with responsiveness to conscious reward cues also influence responsiveness to unconscious reward cues. Participants with low and high levels of Novelty Seeking (NS) performed updating tasks in which they could either gain 1 euro or 5 cents. Gains were presented either supraliminally or subliminally at the beginning of each trial. Results showed that low NS participants performed better in the high-reward than in the low-reward condition, whereas high NS participants' performance did not differ between reward conditions. Interestingly, we found that low NS participants performed significantly better when rewards were presented unconsciously, whereas high NS participants' performance did not differ whether reward cues were presented subliminally or supraliminally. Our findings highlight the necessity of taking personality into account in unconscious cognition research. They also suggest that individual differences might determine whether implicit and explicit motives have similar or complementary influences.     

Autobiographical memory style in seasonal affective disorder and its relationship to future symptom remission

Autobiographical memory was examined in participants with seasonal affective disorder (SAD). In Experiment 1, participants with SAD performed an autobiographical memory task (AMT) in the winter, when depressed. The AMT required participants to generate autobiographical memories to positive and negative cue words. Symptom levels were reassessed in the summer, when participants were remitted. The number of overly general memories to positive cues generated when the SAD participants were depressed predicted symptom levels when remitted, over and above initial symptom levels, with greater winter overgenerality being associated with high levels of summer symptoms. However, this was dependent on the exact measure of depressive symptoms used. The degree of overgenerality of memories in SAD participants was further investigated in Experiment 2. Results revealed that SAD participants did not show elevated recall of overgeneral memories relative to controls. The results as a whole indicate that, even when levels of general memories are no greater in a given target group than in controls, the absolute level of general memories to positive cue words is still independently related to symptom outcome.     

Differential effects of safety in extinction of anxious responding to a CO2 challenge in patients with panic disorder

Safety-relevant parameters are hypothesized to be important to the maintenance of pathological anxiety. The authors examined the effects of safety information and safety cues on anxious responding to a repeated 35% CO2 challenge in 31 patients with panic disorder. Patients were randomly assigned to one of three conditions: (a) safety information, (b) safety information plus a safety cue, or (c) no safety information. In the safety information group, patients received accurate information regarding the benign effects of the CO2 challenge. In the combined group, patients also received a safety cue that is salient for many patients with panic disorder (i.e., access to an anxiolytic pill during the challenge). The experimental manipulations did not differentially affect anxious responding following an initial challenge. However, after access to the anxiolytic was removed and the challenge procedure was repeated, those in the safety information alone condition showed lower subjective anxiety compared to those in the combined safety information/safety cue group. Findings suggest that safety information facilitates extinction of anxiety but only in the absence of safety cues.     

Higher-order retrospective revaluation in human causal learning

Previous studies demonstrated that participants will retrospectively adjust their ratings about the relation between a target cue and an outcome on the basis of information about the causal status of a competing cue that was previously paired with the target cue. We demonstrate that such retrospective revaluation effects occur not only for target cues with which the competing cue was associated directly, but also for target cues that were associated indirectly with the competing cue. These second-order and third-order retrospective revaluation effects are compatible with certain implementations of the probabilistic contrast model and with a modified, extended comparator model, but cannot be explained on the basis of a revised Rescorla-Wagner model or a revised SOP model.     

Stronger renewal in human fear conditioning when tested with an acquisition retrieval cue than with an extinction retrieval cue

It was previously demonstrated in our laboratory that conditioned fear in humans can renew after extinction, when this procedure took place in a different context (ABA-renewal [Vansteenwegen et al. (2005). Return of fear in a human differential conditioning paradigm caused by a return to the original acquisition context. Behaviour Research and Therapy, 43(3), 323–336]). Using the same experimental design, we now tested the power of retrieval cues to interact with this contextual renewal phenomenon. Two groups went through acquisition and extinction (in a different context). They were then tested in the original acquisition context and in the presence of a retrieval cue. In the acquisition-cue group, this cue previously featured during the acquisition procedure; in the extinction-cue group, the cue previously featured during the extinction procedure. As expected, renewal of conditioned electro-dermal responding and retrospective expectancy ratings was strongest in the acquisition-cue group. Theoretical and clinical implications of this finding are discussed.     

Autobiographical memory specificity after manipulating retrieval cues in adults reporting childhood sexual abuse

Traumatized samples have relative difficulty in generating specific autobiographical memories on a cue word task, compared to nonexposed controls. Simultaneously, trauma is associated with highly specific intrusive trauma memories in day-to-day life. Possibly, day-to-day intrusions and memories generated to cue words rely on different retrieval processes, with the former dependent on close associations between retrieval cues and specific memory representations (direct retrieval), and the latter on iterative retrieval cycles through a hierarchical memory system (generative retrieval). This study investigated this distinction using two versions of the cue word task, designed to promote generative and direct retrieval, respectively, in participants with or without a history of child sexual abuse (CSA). The data demonstrated that CSA participants were less specific than nonabused controls to generative retrieval cues, but this difference disappeared with direct retrieval cues. This interaction was stronger in CSA participants with relatively greater posttraumatic stress and remained significant when participants with past or current major depressive disorder were excluded and also when only those participants with corroborated CSA were included.