Effects of extended context discrimination training and context extinction on transfer of context dependency of conditioned flavor aversion

We trained rats in a context discrimination paradigm by pairing a sucrose solution with lithium chloride in one context (conditioning context) and simple exposure to the same fluid in a second (neutral) context to establish a context-dependent aversion to the conditioned fluid. We then investigated whether transfer of the context dependency to a test fluid (a sodium chloride solution) was affected by two post-discrimination training treatments, an extended context discrimination training, and non-reinforced exposure to the conditioning context (context extinction). We found that the context-dependent flavor aversion that had been specific to sucrose transferred to the test fluid after the extensive training (Experiment 1). Context extinction eliminated the transfer effect that had been observed immediately after the context discrimination training (Experiment 2). In addition, an aversion acquired by sucrose through a simple conditioning of sucrose-LiCl pairings did not generalize to the test fluid (Experiment 3). These results emphasize the importance of a Pavlovian excitatory association between the conditioning context and nausea as a primary source of transfer of the context dependency, rather than a generalization of aversion acquired by the conditioned fluid to the test fluid. © 2014 Elsevier B.V

Intraday Activity Levels May Better Reflect the Differences Between Major Depressive Disorder and Bipolar Disorder Than Average Daily Activity Levels

It is important to establish an objective index to differentiate mood disorders (i.e., bipolar disorder; BD and major depressive disorder; MDD). The present study focused on the pattern of changes of physical activity in the amount of activity intraday, and examined the relationship between activity patterns and mood disorders. One hundred and eighteen inpatients with MDD or BD in a depressive state provided the activity data by using wearable activity trackers for 3 weeks. In order to illuminate the characteristic patterns of intraday activities, Principal Component Analysis (PCA) was adopted to extract the main components of intraday activity changes. We found that some of the PCs reflected the differences between the types of mood disorder. BD participants showed high activity pattern in the morning and low activity pattern in evenings. However, MDD showed the opposite. Our results suggest that activity tracking focused on daytime activity patterns may provide objective auxiliary diagnostic information

ABA, ABC, and AAB renewal in fear conditioning using social stimuli and its quantitative description

A relapse in clinical anxiety following exposure therapy for social anxiety disorder is prevalent and causes serious problems. According to the fear conditioning theory of social anxiety disorder, a part of this relapse can be caused by the renewal effect. This study aimed to investigate whether three renewal effects occur in a fear conditioning procedure that uses social stimuli as both unconditioned and conditioned stimuli, which is an analog preparation of acquisition of social anxiety and reduction by exposure therapy. Sixty-four participants were randomly allocated to four groups (AAA, ABA, ABC, and AAB). They received 9 pairings with a natural face and a negative comment during the acquisition phase and then received 18 pairings with the same face and a neutral comment from the person in the extinction phase. Following extinction, the testing phase was conducted. Context, defined as background colors, used in each phase was different between groups. We conducted two analyses, the ANOVA and Bayesian modeling, to investigate whether three types of renewal effects occur, whether the individual data can be described by an associative model and whether individual differences in learning are related to social anxiety. The ANOVA showed the occurrence of three renewals in the procedure, although the size of their effects was the same. The Bayesian modeling indicated that individual data were generally consistent with the model, and there were some relationships among the estimated parameters and between their parameters and social anxiety. These findings suggest that the relapse following exposure therapy is related to renewal effects, the effect of each exposure session can be represented by mathematical associative models, and some features of learning in the procedure are related to other features and social anxiety

Learning About Absent Outcome in the Presence of Conditioned Excitor and Inhibitor: A Study Using Conditioned Flavor Preference

We examined whether aversive conditioning of a previously established conditioned inhibitor (A) for sucrose solution (X) affects subsequent consumption and aversive conditioning of X. Experiment 1 established an appetitive conditioned inhibition procedure in which odor A became a conditioned inhibitor for X. In Phase 1 of Experiments 2 and 3, subjects received either inhibitory (Group INH: AB/BX/C) or excitatory conditioning of A (Group EXC: ABX/B/C), or a control treatment (GroupCONT: AB/B/CX). In Phase 2, A was paired with an injection of lithium chloride (LiCl) and consumption of X was measured. X was paired with LiCl in Phase 3, and tested in extinction. After a moderate amount of Phase 1 treatment in Experiment 2, animals in Group EXC showed a reduction in consumption of X after A-LiCl pairings, while those in both Groups EXC and INH rapidly acquired an aversion to X during X-LiCl conditioning. However, when extended Phase 1 treatment was given in Experiment 3, animals in Group INH tended to acquire the aversion to X at a slower rate than those in Group CONT. Animals in Group EXC did not show any superiority in acquisition of theX aversion. The results are discussed in terms of mediation processes by event representations

Learning About Absent Outcome in the Presence of Conditioned Excitor and Inhibitor: A Study Using Conditioned Flavor Preference

We examined whether aversive conditioning of a previously established conditioned inhibitor (A) for sucrose solution (X) affects subsequent consumption and aversive conditioning of X. Experiment 1 established an appetitive conditioned inhibition procedure in which odor A became a conditioned inhibitor for X. In Phase 1 of Experiments 2 and 3, subjects received either inhibitory (Group INH: AB/BX/C) or excitatory conditioning of A (Group EXC: ABX/B/C), or a control treatment (GroupCONT: AB/B/CX). In Phase 2, A was paired with an injection of lithium chloride (LiCl) and consumption of X was measured. X was paired with LiCl in Phase 3, and tested in extinction. After a moderate amount of Phase 1 treatment in Experiment 2, animals in Group EXC showed a reduction in consumption of X after A-LiCl pairings, while those in both Groups EXC and INH rapidly acquired an aversion to X during X-LiCl conditioning. However, when extended Phase 1 treatment was given in Experiment 3, animals in Group INH tended to acquire the aversion to X at a slower rate than those in Group CONT. Animals in Group EXC did not show any superiority in acquisition of theX aversion. The results are discussed in terms of mediation processes by event representations