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Learning is a functional state of the brain that should be understood as a continuous process, rather than being restricted to the very moment of its acquisition, storage, or retrieval. The cerebellum operates by comparing predicted states with actual states, learning from errors, and updating its internal representation to minimize errors. In this regard, we studied cerebellar interpositus nucleus (IPn) functional capabilities by recording its unitary activity in behaving rabbits during an associative learning task: the classical conditioning of eyelid responses. We recorded IPn neurons in rabbits during classical eyeblink conditioning using a delay paradigm. We found that IPn neurons reduce error signals across conditioning sessions, simultaneously increasing and transmitting spikes before the onset of the unconditioned stimulus. Thus, IPn neurons generate predictions that optimize in time and shape the conditioned eyeblink response. Our results are consistent with the idea that the cerebellum works under Bayesian rules updating the weights using the previous history.

Before implementing the Competency-Based Approach (CBA) in 2003, the Algerian educational system was based on traditional teaching methods that focused mainly on acquiring the knowledge about language delivered by the teacher and the amount of information the learner could accumulate to pass the exams. Although CBA has shifted the teacher's role from a knowledge transmitter to a facilitator and the learner from a passive recipient to an active participant, the teacher-centered paradigm still prevails among secondary-school teachers. To shed light on that prevalence, the researcher attempts to explore the perceptions secondary-school teachers hold about Teacher-Centred Approach (TCA) and the reasons behind its widespread use. Therefore, the present study investigates the causes of TCA prevalence in English as a Foreign Language (EFL) classes using a mixed-methods approach. To reach that aim, the researcher put forward the following hypothesis. Although teachers know the various teaching approaches, they have to adopt the teacher-centered method because of several constraints. To collect the necessary data to identify those constraints, thirty English teachers from some secondary schools in the district of Mostaganem received a questionnaire. The research results confirmed the hypothesis stated above. They revealed that teachers are well-informed about the viability of various teaching approaches and methods; however, they keep adopting the teacher-centered approach. Such behavior is due to multiple constraints such as classrooms crowdedness, the traditional physical classroom environment, the baccalaureate (BAC) exam requirements, and the time restrictions due to the lengthy English programs.

Conditioned reinforcers are widely used in applied behavior analysis. Basic research evidence reveals that Pavlovian learning plays an important role in the acquisition and efficacy of new conditioned-reinforcer functions. Thus, a better understanding of Pavlovian principles holds the promise of improving the efficacy of conditioned reinforcement in applied research and practice. This paper surveys how (and if) Pavlovian principles are presented in behavior-analytic textbooks; imprecisions and knowledge gaps within contemporary Pavlovian empirical findings are highlighted. Thereafter, six practical principles of Pavlovian conditioning are presented along with empirical support and knowledge gaps that should be filled by applied and translational behavior-analytic researchers. Innovative applications of these principles are outlined for research in language acquisition, token reinforcement, and self-control.

Eyeblink conditioning is used in many species to study motor learning and make inferences about cerebellar function. However, the discrepancies in performance between humans and other species combined with evidence that volition and awareness can modulate learning suggest that eyeblink conditioning is not merely a passive form of learning that relies on only the cerebellum. Here we explored two ways to reduce the influence of volition and awareness on eyeblink conditioning: (1) using a short interstimulus interval, and (2) having participants do working memory tasks during the conditioning. Our results show that participants trained with short interstimulus intervals (150 ms and 250 ms) produce very few conditioned responses after 100 trials. Participants trained with a longer interstimulus interval (500 ms) who simultaneously did working memory tasks produced fewer conditioned responses than participants who watched a movie during the training. Our results suggest that having participants perform working memory tasks during eyeblink conditioning can be a viable strategy for studying cerebellar learning that is absent of influences from awareness and volition. This could enhance the comparability of the results obtained in human studies with those in animal models.

One of the major questions in psychology is whether associative and nonassociative learning are fundamentally different or whether they involve similar processes and mechanisms. We have addressed this question by comparing mechanisms of a nonassociative form of learning, sensitization, and an associative form of learning, classical conditioning of the siphon-withdrawal reflex of hermaphroditic Aplysia. In an analog of differential conditioning, action potentials in one siphon sensory neuron (SN) were paired with shock to the pedal nerves, producing activity-dependent presynaptic facilitation, and action potentials in another SN were unpaired with the shock as a control. The difference between paired and unpaired training is a measure of associative plasticity. Before and after this training, we voltage clamped each SN and measured the outward current during depolarizing pulses. There was a significantly greater decrease in the net outward current in the paired SN than in the unpaired SN. We obtained similar results when we substituted the depolarizing voltage clamp pulse for action potentials during training. We then bathed the ganglion in serotonin as a measure of nonassociative plasticity. The current that was modulated differentially (paired-unpaired) had time and voltage dependencies similar to the current that was modulated by serotonin (Is). These results suggest that an associative form of plasticity, activity-dependent presynaptic facilitation underlying conditioning, involves enhanced modulation of the same ionic current as a nonassociative form, normal presynaptic facilitation underlying sensitization.

The present study aims to understand children's behavior within classroom settings in terms of conditioning theories. It was designed based on grounded theory. Data were collected through participant observation and 98 children whose ages varied between 6 and 10 years were observed. Data were inductively analyzed. Findings indicated that kindergarteners and first graders tend toward classical conditioning and need more teacher control to adjust to classroom settings, whereas children aged from 9 to 10 years behave based on operant conditioning. It is proposed that differences in conditioning stem from teachers' classroom management strategies, and cognitive development.

Pavlovian aversive conditioning is a fundamental form of learning helping organisms survive in their environment. Previous research has suggested that organisms are prepared to preferentially learn to fear stimuli that have posed threats to survival across evolution. Here, we examined whether enhanced Pavlovian aversive conditioning can occur to stimuli that are relevant to the organism's concerns beyond biological and evolutionary considerations, and whether such preferential learning is modulated by inter-individual differences in affect and motivation. Seventy-two human participants performed a spatial cueing task where the goal-relevance of initially neutral stimuli was experimentally manipulated. They subsequently underwent a differential Pavlovian aversive conditioning paradigm, in which the goal-relevant and goal-irrelevant stimuli served as conditioned stimuli. Skin conductance response was recorded as an index of the conditioned response and participants' achievement motivation was measured to examine its impact thereon. Results show that achievement motivation modulated Pavlovian aversive learning to goal-relevant vs. goal-irrelevant stimuli. Participants with high achievement motivation more readily acquired a conditioned response to goal-relevant compared with goal-irrelevant stimuli than did participants with lower achievement motivation. However, no difference was found between goal-relevant and goal-irrelevant stimuli during extinction. These findings suggest that stimuli that are detected as relevant to the organism can induce facilitated Pavlovian aversive conditioning even though they hold no inherent threat value and no biological evolutionary significance, and that the occurrence of such learning bias is critically dependent on inter-individual differences in the organism's concerns, such as achievement motivation.

Two experiments tested whether a peak-shifted generalization gradient could be explained by the averaging of distinct gradients displayed in subgroups reporting different generalization rules. Across experiments using a causal judgment task (Experiment 1) and a fear conditioning paradigm (Experiment 2), we found a close concordance between self-reported rules and generalization gradients using a continuous stimulus dimension (hue). Both experiments also showed an overall peak-shifted gradient after differential conditioning, but not after single cue conditioning. Importantly, the peak shift could be decomposed into linear and peaked gradients when participants were divided into rule subgroups. Our results highlight the need to consider individual differences in the rules that participants derive in human generalization studies and suggest that in some situations, peak shift may be a consequence of averaging across diverse rule subgroups.

Long-term but not short-term memory and synaptic plasticity in many brain areas require neurotrophin signaling, transcription, and epigenetic mechanisms including DNA methylation. However, it has been difficult to relate these cellular mechanisms directly to behavior because of the immense complexity of the mammalian brain. To address that problem, we and others have examined numerically simpler systems such as the hermaphroditic marine mollusk "Aplysia californica". As a further simplification, we have used a semi-intact preparation of the "Aplysia" siphon withdrawal reflex in which it is possible to relate cellular plasticity directly to behavioral learning. We find that inhibitors of neurotrophin signaling, transcription, and DNA methylation block sensitization and classical conditioning beginning ~1h after the start of training, which is in the time range of an intermediate-term stage of plasticity that combines elements of short- and long-term plasticity and may form a bridge between them. Injection of decitabine (an inhibitor of DNA methylation that may have other actions in these experiments) into an LE sensory neuron blocks the neural correlates of conditioning in the same time range. In addition, we found that both DNA and RNA methylation in the abdominal ganglion are correlated with learning in the same preparations. These results begin to suggest the functions and integration of these different molecular mechanisms during behavioral learning.

Considerable research has examined the contrasting predictions of configural and elemental associative accounts of learning. One of the simplest methods to distinguish between these approaches is the summation test, in which the associative strength of a novel compound (AB) made of two separately-trained cues (A+ and B+) is examined. The configural view predicts that the strength of the compound will approximate the average strength of its components, whereas the elemental approach predicts that the strength of the compound will be greater than the strength of either component. The summation test has lead to contradictory evidence in experiments with animals as well as with human adults. The purpose of this research was to examine summation in predictive learning of 5-9 years old children. The results provided evidence of summation (i.e., AB greater than A and B) after training with a "simple summation" procedure (A+ B+ test with AB; Experiment 1, n = 26); but no summation following a "preserved conditioned inhibition" procedure (i.e., A+ B- AB- followed by B+; and test with AB; Experiment 2, n = 26). In Experiment 3, both effects were simultaneously observed (n = 14). These results are consistent with reported findings in both Pavlovian conditioning with animals and predictive learning with adult humans. Theoretical alternatives within the elemental and configural approaches are discussed. (Contains 1 table and 4 figures.)

Acquisition and maintenance of touch-screen responding was examined in naive cynomolgus monkeys ("Macaca fascicularis") under automaintenance and classical conditioning arrangements. In the first condition of Experiment 1, we compared acquisition of screen touching to a randomly positioned stimulus (a gray square) that was either stationary or moving under automaintenance (i.e., banana pellet delivery followed an 8-s stimulus presentation or immediately upon a stimulus touch). For all subjects stimulus touching occurred within the first session and increased to at least 50% of trials by the end of four sessions (320 trials). In the subsequent condition, stimulus touching further increased under a similar procedure in which pellets were only delivered if a stimulus touch occurred (fixed ratio 1 with 8-s limited hold). In Experiment 2, 6 naive subjects were initially exposed to a classical conditioning procedure (8-s stimulus preceded pellet delivery). Despite the absence of a programmed response contingency, all subjects touched the stimulus within the first session and responded on about 50% or more of trials by the second session. Responding was also sensitive to negative, neutral, and positive response contingencies introduced in subsequent conditions. Similar to other species, monkeys engaged in stimulus-directed behavior when stimulus presentations were paired with food delivery. However, stimulus-directed behavior quickly conformed to response contingencies upon subsequent introduction. Video recordings of sessions showed topographies of stimulus-directed behavior that resembled food acquisition and consumption. (Contains 1 table and 7 figures.)

Sign-tracking is a form of autoshaping where animals develop conditioned responding directed toward stimuli predictive of an outcome even though the outcome is not contingent on the animal's behavior. Sign-tracking behaviors are thought to arise out of the attribution of incentive salience (i.e., motivational value) to reward-predictive cues. It is not known how incentive salience would be attributed to serially occurring cues, despite cues often occurring in a sequence in the real world as reward approaches. The experiments presented here demonstrate that reward-proximal cue responding is not altered by the presence of a distal reward cue (Experiment 1), and similarly that reward-distal cue responding which animals favor, is not altered by the presence of a reward-proximal cue (Experiment 2). Extinction of reward-proximal cues after training of the serial sequence leads to a generalized reduction in lever responding (Experiment 3). Together, we show that both Pavlovian serial lever cues acquire motivational value. These experiments also provide support to the notion that sign-tracking responses are insensitive to changes in outcome value, and that responding to serial cues creates a distinct context for outcome value.

Fear-relevant stimuli such as snakes and spiders are thought to capture attention due to evolutionary significance. Classical conditioning experiments indicate that these stimuli accelerate learning, while instructed extinction experiments suggest they may be less responsive to instructions. We manipulated stimulus type during instructed aversive reversal learning and used quantitative modeling to simultaneously test both hypotheses. Skin conductance reversed immediately upon instruction in both groups. However, fear-relevant stimuli enhanced dynamic learning, as measured by higher learning rates in participants conditioned with images of snakes and spiders. Results are consistent with findings that dissociable neural pathways underlie feedback-driven and instructed aversive learning.

This study sought to further investigate the effects of an observational intervention for two participants on the reinforcing property of pieces of string. Pre-observational intervention data showed that the neutral stimuli (strings) did not function to reinforce two participants' responding to a performance task or learning three new skills that were not previously in their repertoires. The observational intervention involved the participants observing a peer confederate receive strings following responses that the participants could not see while they were deprived strings, regardless of whether their responses were correct or incorrect. Once the participants met criterion for terminating the intervention the same performance and learning tasks were again presented. The data showed that the strings now functioned to reinforce both performance and learning tasks. The results are discussed in terms of the utility of this procedure as an alternative to traditional stimulus-stimulus pairing procedures for conditioning neutral stimuli as reinforcers. (Contains 3 tables and 5 figures.)

We begin with the suggestion that the definition of Attention Deficit Hyperactive Disorder (ADHD) still faces some challenges. Conceptually, inhibition of the Pavlovian kind preexisted the "behavioral inhibition" popular in the USA; the difference between them has to be understood in order to understand ADHD. The present project examines the relationship between a teacher rating scale for student attention and the Cognitive Assessment System's measure of Attention in contrast to Planning. The participants were 82 Grade 3 and Grade 4 children from the First Nations community (Cree). Students were administered the Planning and Attention tests of the Cognitive Assessment System (CAS), while teachers rated their own students by using the Attention Checklist (ACL). Correlations between the ACL and the CAS Attention and Planning scores were positive and significant. However, based on the ACL, groups of low- and high-attention participants were contrasted on Attention and Planning scores; tests showed significant differences between the low- and hig-attention participants in the Attention score but not in Planning. (Contains 3 tables.)

Rodrigo, Chamizo, McLaren, & Mackintosh (1997) demonstrated the blocking effect in a navigational task using a swimming pool: rats initially trained to use three landmarks (ABC) to find an invisible platform learned less about a fourth landmark (X) added later than did rats trained from the outset with these four landmarks (ABCX). The aim of the experiment reported here was to demonstrate unblocking using a similar procedure as in the previous work. Three groups of rats were initially trained to find an invisible platform in the presence of three landmarks: ABC for the Blocking and Unblocking groups and LMN for the Control group. Then, all animals were trained to find the platform in the presence of four landmarks, ABCX. In this second training, unlike animals in the Blocking group to which only a new landmark (X) was added in comparison to the first training, the animals in the Unblocking group also had a change in the platform position. In the Control group, both the four landmarks and the platform position were totally new at the beginning of this second training. As in Rodrigo et al. (1997) a blocking effect was found: rats in the Blocking group learned less with respect to the added landmark (X) than did animals in the Control group. However, rats in the Unblocking group learned about the added landmark (X) as well as did animals in the Control group. The results are interpreted as an unblocking effect due to a change in the platform position between the two phases of training, similarly to what is normal in classical conditioning experiments, in which a change in the conditions of reinforcement between the two training phases of a blocking design produce an attenuation or elimination of this effect. These results are explained within an error-correcting connectionist account of spatial navigation (McLaren, 2002). (Contains 2 figures.)

The behavioral processes through which people react appropriately to verbal descriptions remain poorly understood. I argue here that these processes are Pavlovian. Common objections to a Pavlovian account of symbolic behavior evidence a lack of familiarity with the relevant data or misunderstandings of operant theory. Although much remains to be done to explore the relation between verbal understanding and simpler forms of Pavlovian conditioning, the similarity of these two sets of phenomena has received increasing support in recent years. The difficulties of operant principles in accounting for symbolic behavior have a more general implication: Operant models, which focus on the maintenance of responding, must incorporate principles of behavioral induction that explain the origins of novel environment-behavior relations. Pavlovian processes are likely to contribute.

In four conditioned taste aversion experiments with rats as subjects, the effects of extinguished or pre-exposed flavors on retardation and summation tests was compared. Experiment 1 showed that when steps were taken to ensure similar exposure to the target flavor in all conditions, acquisition after pre-exposure and reacquisition after extinction proceeded at a similar rate and was slower than acquisition in a new stimulus control condition. In Experiment 2, reacquisition occurring 2 days after extinction was again slower than acquisition to a new stimulus, but this retardation disappeared when extinction and reacquisition were separated by a 21 days interval. Experiment 3 showed that both an extinguished and a pre-exposed flavor produced a similar summation effect, attenuating the aversion to a previously conditioned flavor. Finally, Experiment 4 showed that this attenuation was also produced by a new flavor. These results suggest, first, that retarded acquisition after extinction of a conditioned taste aversion might be the result of latent inhibition produced by extended experience with the flavor during extinction and, second, that attenuation of aversion to a test excitor on a summation test might not reflect any specific learning process but be simply due to stimulus generalization decrement. (Contains 4 tables and 4 figures.)

The creation of auditory threat Pavlovian memory requires an initial learning stage in which a neutral conditioned stimulus (CS), such as a tone, is paired with an aversive one (US), such as a shock. In this phase, the CS acquires the capacity of predicting the occurrence of the US and therefore elicits conditioned defense responses. Norepinephrine (NE), through ß-adrenergic receptors in the amygdala, enhances threat memory by facilitating the acquisition of the CS-US association, but the nature of this effect has not been described. Here we show that NE release, induced by the footshock of the first conditioning trial, promotes the subsequent enhancement of learning. Consequently, blocking NE transmission disrupts multitrial but not one-trial conditioning. We further found that increasing the time between the conditioning trials eliminates the amplificatory effect of NE. Similarly, an unsignaled footshock delivered in a separate context immediately before conditioning can enhance learning. These results help define the conditions under which NE should and should not be expected to alter threat processing and fill an important gap in the understanding of the neural processes relevant to the pathophysiology of stress and anxiety disorders.

Traumatic experiences early in life can contribute to the development of mood and anxiety disorders that manifest during adolescence and young adulthood. In young rats exposed to acute fear or stress, alterations in neural development can lead to enduring behavioral abnormalities. Here, we used a modified extinction intervention (retrieval+extinction) during late adolescence (post-natal day 45 [p45]), in rats, to target auditory Pavlovian fear associations acquired as juveniles (p17 and p25). The effects of adolescent intervention were examined by assessing freezing as adults during both fear reacquisition and social transmission of fear from a cagemate. Rats underwent testing or training at three time points across development: juvenile (p17 or p25), adolescent (p45), and adult (p100). Retrieval+extinction during late adolescence prevented social reinstatement and recovery over time of fears initially acquired as juveniles (p17 and p25, respectively). Adolescence was the only time point tested here where retrieval+extinction prevented fear recall of associations acquired 20+ days earlier.

The transcription factor cAMP-response element-binding protein (CREB) is involved in neuronal plasticity. Phosphorylation activates CREB and an increased level of phosphorylated CREB is regarded as an indicator of CREB-dependent transcriptional activation. In honeybees ("Apis mellifera") we recently demonstrated a particular high abundance of the phosphorylated honeybee CREB homolog (pAmCREB) in the central brain and in a subpopulation of mushroom body neurons. We hypothesize that these high pAmCREB levels are related to learning and memory formation. Here, we tested this hypothesis by analyzing brain pAmCREB levels in classically conditioned bees and bees experiencing unpaired presentations of conditioned stimulus (CS) and unconditioned stimulus (US). We demonstrate that both behavioral protocols display differences in memory formation but do not alter the level of pAmCREB in bee brains directly after training. Nevertheless, we report that bees responding to the CS during unpaired stimulus presentations exhibit higher levels of pAmCREB than nonresponding bees. In addition, Trichostatin A, a histone deacetylase inhibitor that is thought to enhance histone acetylation by CREB-binding protein, increases the bees' CS responsiveness. We conclude that pAmCREB is involved in gating a bee's behavioral response driven by an external stimulus.

This study examines the role of stimulus duration in learning and memory formation of honeybees ("Apis mellifera"). In classical appetitive conditioning honeybees learn the association between an initially neutral, conditioned stimulus (CS) and the occurrence of a meaningful stimulus, the unconditioned stimulus (US). Thereby the CS becomes a predictor for the US eliciting a conditioned response (CR). Here we study the role of US duration in classical conditioning by examining honeybees conditioned with different US durations. We quantify the CR during acquisition, memory retention, and extinction of the early long-term memory (eLTM), and examine the molecular mechanisms of eLTM by interfering with protein synthesis. We find that the US duration affects neither the probability nor the strength of the CR during acquisition, eLTM retention, and extinction 24 h after conditioning. However, we find that the resistance to extinction 24 h after conditioning is susceptible to protein synthesis inhibition depending on the US duration. We conclude that the US duration does not affect the predictability of the US but modulates the protein synthesis underlying the eLTM's strength. Thus, the US duration differentially impacts learning, eLTM strength, and its underlying protein synthesis

We have previously shown that intracerebellar infusion of the neuropeptide secretin enhances the acquisition phase of eyeblink conditioning (EBC). Here, we sought to test whether endogenous secretin also regulates EBC and to test whether the effect of exogenous and endogenous secretin is specific to acquisition. In Experiment 1, rats received intracerebellar infusions of the secretin receptor antagonist 5-27 secretin or vehicle into the lobulus simplex of cerebellar cortex immediately prior to sessions 1-3 of acquisition. Antagonist-infused rats showed a reduction in the percentage of eyeblink CRs compared with vehicle-infused rats. In Experiment 2, rats received intracerebellar infusions of secretin or vehicle immediately prior to sessions 1-2 of extinction. Secretin did not significantly affect extinction performance. In Experiment 3, rats received intracerebellar infusions of 5-27 secretin or vehicle immediately prior to sessions 1-2 of extinction. The secretin antagonist did not significantly affect extinction performance. Together, our current and previous results indicate that both exogenous and endogenous cerebellar secretin modulate acquisition, but not extinction, of EBC. We have previously shown that (1) secretin reduces surface expression of the voltage-gated potassium channel a-subunit Kv1.2 in cerebellar cortex and (2) intracerebellar infusions of a Kv1.2 blocker enhance EBC acquisition, much like secretin. Kv1.2 is almost exclusively expressed in cerebellar cortex at basket cell-Purkinje cell pinceaus and Purkinje cell dendrites; we propose that EBC-induced secretin release from PCs modulates EBC acquisition by reducing surface expression of Kv1.2 at one or both of these sites.

The honeybee ("Apis mellifera") has long served as an invertebrate model organism for reward learning and memory research. Its capacity for learning and memory formation is rooted in the ecological need to efficiently collect nectar and pollen during summer to ensure survival of the hive during winter. Foraging bees learn to associate a flower's characteristic features with a reward in a way that resembles olfactory appetitive classical conditioning, a learning paradigm that is used to study mechanisms underlying learning and memory formation in the honeybee. Due to a plethora of studies on appetitive classical conditioning and phenomena related to it, the honeybee is one of the best characterized invertebrate model organisms from a learning psychological point of view. Moreover, classical conditioning and associated behavioral phenomena are surprisingly similar in honeybees and vertebrates, suggesting a convergence of underlying neuronal processes, including the molecular mechanisms that contribute to them. Here I review current thinking on the molecular mechanisms underlying long-term memory (LTM) formation in honeybees following classical conditioning and extinction, demonstrating that an in-depth analysis of the molecular mechanisms of classical conditioning in honeybees might add to our understanding of associative learning in honeybees and vertebrates.

Empirical studies have documented a variety of social abnormalities in infancy that indicate risk for later social and behavioral difficulties. There is very little research illustrating the presence of such behavioral vulnerabilities with frequent repeated measures, and the feasibility of designing interventions for improving social engagement in infants less than 1 year of age. In the context of a multiple baseline research design, three young infants, ages 4, 7, and 9 months, referred for concerns about social engagement were assessed for affect, social interest, eye contact avoidance, and response to name. In addition, the feasibility of implementing an intervention to target social behaviors was examined. Results demonstrated that (a) consistently low or erratic levels of social behavior were evident throughout the baseline assessment period, (b) these patterns could be improved with a brief intervention (a modified Pivotal Response Treatment) showing an immediate increase and stability of social engagement, and (c) social engagement remained at a stable and high level at follow-up. The results are discussed in terms of implications of early assessment and intervention for clinical populations, including infants with autism spectrum disorder.

Spontaneous recovery in extinction appears to be inversely related to the acquisition-to-extinction interval, but it remains unclear why this is the case. Rat subjects trained with one of three interference paradigms exhibited less spontaneous recovery of the original response after delayed than immediate interference, regardless of whether interference resulted in attenuated fear (extinction, CS-Shock followed by CS-noShock), acquisition of conditioned fear (latent inhibition, CS-noShock followed by CS-Shock), or acquisition of a response (counterconditioning, CS-Shock followed by CS-Sucrose). We suggest that delaying interference treatment increases the relative similarity of the interference and test contexts, facilitating retrieval of the interfering association and attenuating recovery of the original response.

Contextual specificity of Latent Inhibition (LI) has been demonstrated using an ample range of experimental procedures. Context dependence has not been consistently obtained, however, when LI has been induced using a Conditioned Taste Aversion (CTA) procedure. This paper presents two experiments designed to analyze whether the context plays the same role in LI with a CTA paradigm as compared to other Pavlovian techniques. Experiment 1 compared the effect on LI of a context change between the conditioning and test stages as a function of whether the testing context was new or the animals' home cage. The results of this experiment showed that using the animals' home cage as context at testing enhanced the expression of LI. Experiment 2 manipulated context novelty and familiarity beforehand to introduce different context changes. The results indicate that, as compared to the no context change condition, the strength of LI increased when the conditioning context was different from that of preexposure and testing (ABA). Conversely, a context change from preexposure to conditioning/test stages (ABB) disrupted LI, but only when the animals had been pre-familiarized with the new context introduced at conditioning. These results are similar to those obtained with other conditioning procedures different from CTA. (Contains 3 tables and 2 figures.)

Four experiments with rats examined Pavlovian incubation, in which responding increases when Pavlovian conditioning is followed by a testing delay. In a within-subjects design, Experiment 1 first showed that when a single food pellet unconditioned stimulus (US) signaled the delivery of three additional pellets, responding after the single US was significantly greater on a delayed, compared to an early, test. Pavlovian incubation was not importantly due to extinction testing (Experiment 2), increased motivation (Experiment 3), or differences in apparatus exposure, or handling cues, during the incubation period (Experiment 4). Implications for theories of conditioning are considered. (Contains 8 figures.)

We used Pavlovian counterconditioning in rats to identify the neural mechanisms for appetitive-aversive motivational interactions. In Stage I, rats were trained on conditioned stimulus (CS)-food (unconditioned stimulus [US]) pairings. In Stage II, this appetitive CS was transformed into a fear CS via pairings with footshock. The development of fear responses was retarded in rats that had received Stage I appetitive training. This counterconditioning was associated with increased levels of phosphorylated mitogen activated protein kinase immunoreactivity (pMAPK-IR) in several brain regions, including midline thalamus, rostral agranular insular cortex (RAIC), lateral amygdala, and nucleus accumbens core and shell, but decreased expression in the ventrolateral quadrant of the midbrain periaqueductal gray. These brain regions showing differential pMAPK-IR have previously been identified as part of the fear prediction error circuit. We then examined the causal role of RAIC MAPK in fear learning and showed that Stage II fear learning was prevented by RAIC infusions of the MEK inhibitor PD098059 (0.5 microgram/hemisphere). Taken together, these results show that there are opponent interactions between the appetitive and aversive motivational systems during fear learning and that the transformation of a reward CS into a fear CS is linked to heightened activity in the fear prediction error circuit.

Conventional wisdom dictates we must face our fears to conquer them. This idea is embodied in exposure-based treatments for anxiety disorders, where the intent of exposure is to reverse a history of avoidant behavior that is thought to fuel a patient's irrational fears. We tested in humans the relationship between fear and avoidance by combining Pavlovian differential fear conditioning with a novel task for quantifying spontaneous passive avoidant behavior. During self-guided navigation in virtual reality following de novo fear conditioning, we observed participants keeping their distance from the feared object. At the individual level, passive avoidant behavior was highly associated with maladaptive fear expression (fear-potentiated startle) during late extinction training, indicating that extinction learning was impaired following a brief episode of avoidance. Avoidant behavior, however, was not related to initial acquired fear, raising doubt about a straightforward link between physiological fear and behavioral avoidance. We conclude that a deeper understanding of what motivates avoidance may offer a target for early intervention, before fears transition from the rational to the irrational.

Modifications in chromatin structure have been widely implicated in memory and cognition, most notably using hippocampal-dependent memory paradigms including object recognition, spatial memory, and contextual fear memory. Relatively little is known, however, about the role of chromatin-modifying enzymes in amygdala-dependent memory formation. Here, we use a combination of biochemical, behavioral, and neurophysiological methods to systematically examine the role of p300/CBP histone acetyltransferase (HAT) activity in the consolidation and reconsolidation of auditory Pavlovian fear memories. We show that local infusions of c646, a selective pharmacological inhibitor of p300/CBP activity, shortly following either fear conditioning or fear memory retrieval impair training and retrieval-related regulation of histone acetylation in the lateral nucleus of the amygdala (LA). Furthermore, we show that intra-LA infusion of c646 significantly impairs fear memory consolidation, reconsolidation, and associated neural plasticity in the LA. Our findings collectively suggest that p300/CBP HAT activity is critical for the consolidation and reconsolidation of amygdala-dependent Pavlovian fear memories.

Rabbits were classically conditioned using compounds of tone and light conditioned stimuli (CSs) presented with either simultaneous onsets (Experiment 1) or serial onsets (Experiment 2) in a delay conditioning paradigm. Training with the simultaneous compound reduced the likelihood of a conditioned response (CR) to the individual CSs ("mutual overshadowing") but left CR timing unaltered. CR peaks were consistently clustered around the time of unconditioned stimulus (US) delivery. Training with the serial compound (CSA [right arrow] CSB [right arrow] US) reduced responding to CSB ("temporal primacy/information effect") but this effect was prevented by prior CSB [right arrow] US pairings. In both cases, serial compound training altered CR timing. On CSA [right arrow] CSB test trials, the CRs were accelerated; the CR peaks occurred after CSB onset but well before the time of US delivery. Conversely, CRs on CSB- trials were decelerated; the distribution of CR peaks was variable but centered well after the US. Timing on CSB-trials was at most only slightly accelerated. The results are discussed with respect to processes of generalization and spectral timing applicable to the cerebellar and forebrain pathways in eyeblink preparations.

Empirical research has shown that the amygdala, hippocampus, and ventromedial prefrontal cortex (vmPFC) are involved in fear conditioning. However, the functional contribution of each brain area and the nature of their interactions are not clearly understood. Here, we extend existing neural network models of the functional roles of the hippocampus in classical conditioning to include interactions with the amygdala and prefrontal cortex. We apply the model to fear conditioning, in which animals learn physiological (e.g. heart rate) and behavioral (e.g. freezing) responses to stimuli that have been paired with a highly aversive event (e.g. electrical shock). The key feature of our model is that learning of these conditioned responses in the central nucleus of the amygdala is modulated by two separate processes, one from basolateral amygdala and signaling a positive prediction error, and one from the vmPFC, via the intercalated cells of the amygdala, and signaling a negative prediction error. In addition, we propose that hippocampal input to both vmPFC and basolateral amygdala is essential for contextual modulation of fear acquisition and extinction. The model is sufficient to account for a body of data from various animal fear conditioning paradigms, including acquisition, extinction, reacquisition, and context specificity effects. Consistent with studies on lesioned animals, our model shows that damage to the vmPFC impairs extinction, while damage to the hippocampus impairs extinction in a different context (e.g., a different conditioning chamber from that used in initial training in animal experiments). We also discuss model limitations and predictions, including the effects of number of training trials on fear conditioning. (Contains 1 table and 11 figures.)

Despite extensive evidence that appetitive memories undergo reconsolidation, two notable failures to observe reconsolidation have been reported: instrumental responding and goal-tracking. However, these studies do not provide conclusive evidence for a lack of memory reconsolidation due to the numerous boundary conditions that dictate whether a memory will undergo reconsolidation. In this study we sought to reexamine reconsolidation in an appetitive, Pavlovian conditioned approach procedure and the behavioral boundary conditions within which memories are destabilized and reconsolidated. This study demonstrated that a Pavlovian goal-tracking memory, previously thought to be resistant to destabilization, will undergo memory reconsolidation under discrete conditions that favor reconsolidation as opposed to extinction, and that this is dependent on the amount of training rats received. With restricted training, systemic administration of MK-801 impaired memory extinction. In contrast, with more extended training, MK-801 administration impaired memory reconsolidation. We also demonstrate that behavioral boundary conditions that exist for appetitive memory reconsolidation are much more complex than simple parametric calculations. Moreover, extinction per se is not a boundary on reconsolidation, in that MK-801 also has no behavioral effect under some conditions.

Protein degradation is known to affect memory formation after extinction learning. We demonstrate here that an inhibitor of protein degradation, MG132, interferes with memory formation after extinction learning in a classical appetitive conditioning paradigm. In addition, we find an enhancement of memory formation when the same inhibitor is applied after initial learning. This result supports the idea that MG132 targets an ongoing consolidation process. Furthermore, we demonstrate that the sensitivity of memory formation after initial learning and extinction learning to MG132 depends in the same way on the number of CS-US trials and the intertrial interval applied during initial learning. This supports the idea that the learning parameters during acquisition are critical for memory formation after extinction and that protein degradation in both learning processes might be functionally linked.

Reinforcing an alternative response in the same context as a target response reduces the rate of occurrence but increases the persistence of that target response. Applied researchers who use such techniques to decrease the rate of a target problem behavior risk inadvertently increasing the persistence of the same problem behavior. Behavioral momentum theory asserts that the increased persistence is a function of the alternative reinforcement enhancing the Pavlovian relation between the target stimulus context and reinforcement. A method showing promise for reducing the persistence-enhancing effects of alternative reinforcement is to train the alternative response in a separate stimulus context before combining with the target stimulus in extinction. The present study replicated previous findings using pigeons by showing that combining an "alternative" richer VI schedule (96 reinforcers/hr) with a "target" leaner VI schedule (24 reinforcers/hr) reduced resistance to extinction of target responding compared with concurrent training of the alternative and target responses (totaling 120 reinforcers/hr). We also found less relapse with a reinstatement procedure following extinction with separate-context training, supporting previous findings that training conditions similarly influence both resistance to extinction and relapse. Finally, combining the alternative stimulus context was less disruptive to target responding previously trained in the concurrent schedule, relative to combining with the target response trained alone. Overall, the present findings suggest the technique of combining stimulus contexts associated with alternative responses with those associated with target responses disrupts target responding. Furthermore, the effectiveness of this disruption is a function of training context of reinforcement for target responding, consistent with assertions of behavioral momentum theory. (Contains 8 figures.)

Evaluative conditioning (EC) refers to changes in people's evaluative responses toward initially neutral stimuli (CSs) by mere spatial and temporal contiguity with other positive or negative stimuli (USs). We investigate whether changing CS features from conditioning to evaluation also changes people's evaluative response toward these CSs. We used computer-generated male faces as CSs and paired them with other positively or negatively evaluated faces. When participants evaluated the CS faces, they either appeared unchanged, with glasses, with beards, or glasses and beards. Unchanged faces showed a clear conditioning effect, while all other face versions showed no significant conditioning effects. The conditioning effect also depended on participants' awareness of a CS's respective US. These results mirror configural explanations of stimulus generalization in classical conditioning, with implications for EC as explanation for attitude acquisition and learning of likes and dislikes in everyday life. (Contains 2 figures and 2 tables.)

Background: Behavioural interventions conceptualise self-injurious behaviour (SIB) as developing from early repetitive behaviours through acquisition of homeostatic functions in regulating stimulation and subsequent shaping into SIB through socially mediated or automatic operant reinforcement. Despite high success rates, such interventions rarely completely eliminate SIB, and overall effectiveness has not increased since the 1960s. Methods: Research (excluding studies of single genetic syndromes) on the early development, functional properties and phenomenology of SIB in persons with intellectual disabilities (IDs) published from 1999 to 2010 inclusive is reviewed. Results: Despite evidence to support the operant shaping hypothesis, in some cases tissue-damaging SIB, especially head-banging, emerges at a similar or younger age than stereotyped behaviours or "proto-SIB", often associated with tantrums following frustrative non-reward and/or abrupt situational transitions. Many young children show undifferentiated patterns of responding in functional analyses of SIB, and SIB is associated with aggression and impulsivity as well as with repetitive behaviour. Conclusions: One dynamic in the development of SIB may be Pavlovian conditioning of aggression, originally elicited by aversive events or frustrative non-reward, to stimuli associated with such situations. Integration into operant technology of interventions based on Pavlovian principles such as graduated exposure (with or without counterconditioning) to aversive stimuli may enhance the effectiveness of behavioural interventions.

The performance of developing zebrafish in both classical and operant conditioning assays was tested with a particular focus on the emergence of these learning behaviors during development. Strategically positioned visual cues paired with electroshocks were used in two fully automated assays to investigate both learning paradigms. These allow the evaluation of the behavioral performance of zebrafish continuously throughout development, from larva to adult. We found that learning improves throughout development, starts reliably around week 3, and reaches adult performance levels at week 6. Adult fish quickly learned to perform perfectly, and the expression of the learned behavior is manifestly controlled by vision. The memory is behaviorally expressed in adults for at least 6 h and retrievable for at least 12 h.

Previous research has found that swim stress during a classical conditioning trial attenuates conditioned taste aversion (CTA). In the current study, rats were used to examine the effects of inescapable swim stress on the habituation of neophobia to a flavored solution and reacquisition of an extinguished conditioned taste aversion. In Experiment 1, subjects were initially exposed to a taste, with some subjects receiving a swim experience to assess the level of neophobia on a subsequent taste-exposure test. Rats in Experiment 2 were given a taste-LiCl trial followed by extensive CS-alone extinction trials. Subjects then received the taste-LiCl pairing again, followed for some by a swim experience to examine its effect on subsequent reconditioning. Swim stress influenced CS processing on the final extinction trial. Thus, reacquisition was attenuated by swim, but there was no effect of swim stress on the attenuation of neophobia. These results are discussed in terms of the effects of stress on CS processing. (Contains 2 tables and 3 figures.)

In conditioned taste aversion (CTA), a taste, the conditioned stimulus (CS), is paired with an illness-inducing stimulus, the unconditioned stimulus (US), to produce CS-US associations at very long (hours) intervals, a result that appears to violate the law of contiguity. The specific length of the maximum effective trace interval that has been reported differs from laboratory to laboratory. Metabolic rate may be a factor that influences the effective CS-US interval. Given that prior handling has been demonstrated to decrease stress and presumably lower metabolism, we examined the effect of handling on the effective CS-US intervals of 0, 90, and 180 min. Results indicated that handling rats for 1 min daily, for 21 days, may have extended the effective CS-US interval to 90 min in contrast to rats that were not handled. This finding indicates that subtle procedural differences may help explain the variability reported for the effective CS-US interval in various CTA studies. (Contains 1 figure.)

The nematode "Caenorhabditis elegans" ("C. elegans") adult hermaphrodite has 302 invariant neurons and is suited for cellular and molecular studies on complex behaviors including learning and memory. Here, we have developed protocols for classical conditioning of worms with 1-propanol, as a conditioned stimulus (CS), and hydrochloride (HCl) (pH 4.0), as an unconditioned stimulus (US). Before the conditioning, worms were attracted to 1-propanol and avoided HCl in chemotaxis assay. In contrast, after massed or spaced training, worms were either not attracted at all to or repelled from 1-propanol on the assay plate. The memory after the spaced training was retained for 24 h, while the memory after the massed training was no longer observable within 3 h. Worms pretreated with transcription and translation inhibitors failed to form the memory by the spaced training, whereas the memory after the massed training was not significantly affected by the inhibitors and was sensitive to cold-shock anesthesia. Therefore, the memories after the spaced and massed trainings can be classified as long-term memory (LTM) and short-term/middle-term memory (STM/MTM), respectively. Consistently, like other organisms including "Aplysia", "Drosophila", and mice, "C. elegans" mutants defective in "nmr-1" encoding an NMDA receptor subunit failed to form both LTM and STM/MTM, while mutations in "crh-1" encoding the CREB transcription factor affected only the LTM.

Pavlovian eyeblink conditioning has been used extensively as a model system for examining the neural mechanisms underlying associative learning. Delay eyeblink conditioning depends on the intermediate cerebellum ipsilateral to the conditioned eye. Evidence favors a two-site plasticity model within the cerebellum with long-term depression of parallel fiber synapses on Purkinje cells and long-term potentiation of mossy fiber synapses on neurons in the anterior interpositus nucleus. Conditioned stimulus and unconditioned stimulus inputs arise from the pontine nuclei and inferior olive, respectively, converging in the cerebellar cortex and deep nuclei. Projections from subcortical sensory nuclei to the pontine nuclei that are necessary for eyeblink conditioning are beginning to be identified, and recent studies indicate that there are dynamic interactions between sensory thalamic nuclei and the cerebellum during eyeblink conditioning. Cerebellar output is projected to the magnocellular red nucleus and then to the motor nuclei that generate the blink response(s). Tremendous progress has been made toward determining the neural mechanisms of delay eyeblink conditioning but there are still significant gaps in our understanding of the necessary neural circuitry and plasticity mechanisms underlying cerebellar learning.

Three conditioned suppression experiments examined the Hall-Pearce (1979) negative transfer effect in rats. Experiment 1 replicated the effect: CS-US[subscript weak] pairings retarded subsequent fear conditioning to the CS as a result of CS-US[subscript strong] pairings. The size of this retardation was less than that produced by non-reinforced CS presentations (latent inhibition). When the magnitude of the US[subscript weak] was reduced in Experiment 2, the Hall-Pearce effect was greater than latent inhibition. Experiment 3 confirmed the findings of the two previous experiments, and demonstrated that magnitude of the Hall-Pearce negative transfer effect is inversely related to the magnitude of the US[subscript weak]. From these findings it is suggested that the Hall-Pearce effect consists of a balance between a positive transfer of associative strength, and negative transfer based on CS- and US-preexposure effects.

Three experiments with rat subjects examined resurgence of an extinguished instrumental response using the procedure introduced by Epstein (1983) with pigeons. There were three phases: (1) initial acquisition of pressing on a lever (L1) for pellet reward, (2) extinction of L1, and (3) a test session in which a second lever (L2) was inserted, briefly reinforced, and then extinguished. Experiment 1 confirmed that if pressing L2 delivered 20 pellets followed by extinction, rats would resume L1 responding in the final test. Experiment 2 compared the effects of response-contingent and non-contingent rewards delivered upon insertion of L2. Although insertion of L2 alone did not increase L1 responding, response-contingent and non-contingent rewards led to comparable increases in L1 responding. Experiment 3 found that the delivery of non-contingent pellets during extinction of L1, which would be expected to reduce the ability of pellets to set the occasion for the L1 response, also reduced the effects of both response-contingent and non-contingent rewards during the final test. The results indicate that in this method, the resurgence treatment leads to an increase in L1 pressing due to simple presentation of the pellet; delivering the reinforcer after extinction of L1 reinstates L1 responding by setting the occasion for the L1 response.

Attentional capture and behavioral control by conditioned stimuli have been dissociated in animals. The current study assessed this dissociation in humans. Participants were trained on a Pavlovian schedule in which 3 visual stimuli, A, B, and C, predicted the occurrence of an aversive noise with 90%, 50%, or 10% probability, respectively. Participants then went on to separate instrumental training in which a key-press response canceled the aversive noise with a 0.5 probability on a variable interval schedule. Finally, in the transfer phase, the 3 Pavlovian stimuli were presented in this instrumental schedule and were no longer differentially predictive of the outcome. Observing times and gaze dwell time indexed attention to these stimuli in both training and transfer. Aware participants acquired veridical outcome expectancies in training--that is, A greater than B greater than C, and these expectancies persisted into transfer. Most important, the transfer effect accorded with these expectancies, A greater than B greater than C. By contrast, observing times accorded with uncertainty--that is, they showed B greater than A = C during training, and B less than A = C in the transfer phase. Dwell time bias supported this association between attention and uncertainty, although these data showed a slightly more complicated pattern. Overall, the study suggests that transfer is linked to outcome prediction and is dissociated from attention to conditioned stimuli, which is linked to outcome uncertainty. (Contains 6 figures, 1 table and 3 footnotes.)