Reconsolidation and memory infidelity in Lymnaea

Lymnaea stagnalis were operantly conditioned to not perform aerial respiratory behaviour in a specific context (i.e. context-1). The memory for this learned response was reactivated 3 days later in context-1. During the 1 h reconsolidation period following memory reactivation, randomly picked snails were either maintained in context-1 or exposed to a new context (i.e. context-2). One hour later in the post-reconsolidation period, snails in context-1 were placed for 1 h in context-2 and vice-versa. In neither the hypoxic reconsolidation nor the post reconsolidation periods did snails receive a reinforcing stimulus when they opened their pneumostome. All snails were blindly tested for memory 24 h later period in context-2. Only those snails that had been exposed to context-2 during the reconsolidation period exhibited 'memory' for context-2. That is, memory infidelity was observed. Snails exposed to context-2 in only the post-reconsolidation period did not show memory for context-2. The immediate cooling of snails after their exposure to the new context in the reconsolidation period blocked the formation the implanted memory. Snails trained in context-1 and exposed to context-2 in the consolidation period only, also did not have memory for context-2. However, the memory for context-1 could still be recalled following successful implantation of the 'new' memory. All data presented here are consistent with the notion that during the reconsolidation process memory can be updated.     

Both exposure to a novel context and associative learning induce an upregulation of AKAP150 protein in mouse hippocampus

A-kinase anchoring protein 150 (AKAP150) is a multi-enzyme signaling complex that coordinates the action of PKA, PKC, and PP2B at neuronal membranes and synapses. We measured levels of AKAP150 protein in the hippocampus 6h after training mice in a contextual fear conditioning paradigm. In contextual fear conditioning mice learn to associate a context with a footshock presentation. Mice were divided in four experimental groups with different training protocols: naive, no footshock exposure, immediate footshock exposure, and footshock 3min after exposure to the context. We found that AKAP150 protein levels were increased upon exposing mice to the novel context independent of the training protocol. However, when the animals were habituated to the experimental context, only mice that learned to associate the context with the footshock showed an upregulation of AKAP150. We suggest that upregulated levels of AKAP150 contribute to processing the exposure to a novel context and associative learning.     

Occasional reinforced responses during extinction can slow the rate of reacquisition of an operant response

Three experiments with rats examined reacquisition of an operant response after either extinction or a response-elimination procedure that included occasional reinforced responses during extinction. In each experiment, reacquisition was slower when response elimination had included occasional reinforced responses, although the effect was especially evident when responding was examined immediately following each response-reinforcer pairing during reacquisition (Experiments 2 and 3). An extinction procedure with added noncontingent reinforcers also slowed reacquisition (Experiment 3). The results are consistent with research in classical conditioning (Bouton, M. E., Woods, A. M., & Pineño, O. (2004). Occasional reinforced trials during extinction can slow the rate of rapid reacquisition. Learning & Motivation, 35, 371-390) and suggest that rapid reacquisition after extinction is analogous to a renewal effect that occurs when reinforced responses signal a return to the conditioning context. Clinical implications are also discussed.     

Transformation of the discriminative and eliciting functions of generalized relational stimuli

In three experiments, match-to-sample procedures were used with undergraduates to establish arbitrary relational functions for three abstract visual stimuli. In the presence of samples A, B, and C, participants were trained to select the smallest, middle, and largest member, respectively, of a series of three-comparison arrays. In Experiment 1, the B (choose middle) stimulus was then used to train a steady rate of keyboard pressing before the A (choose smallest) and the C (choose largest) stimuli were presented. Participants pressed slower to A and faster to C than to B. Then B was paired with mild shock in a Pavlovian procedure with skin conductance change as the dependent variable. When presented with A and C, 6 of 8 experimental participants showed smaller skin conductance changes to A and larger skin conductance changes to C than to B. In Experiment 2, A was then used as a sample in a match-to-sample procedure to establish an arbitrary size ranking among four same-sized colored circle comparisons. One of the middle circles was then used to establish a steady rate of pressing before the other circles were presented. Five of 6 participants responded slower to the "smaller" circle and faster to the "larger" circle than they did to the "middle" circle. In Experiment 3, A, B, and C were then presented on a series of test trials requiring participants to pick the comparison that was less than, greater than, or equal to the sample. Novel stimuli were included on some trials. Results indicated that the relational training procedures produced derived relations among the stimuli used in training and that these allowed correct inferences of relative size ranking among novel stimuli.     

Comparing neurocognitive impairment in schizophrenia and bipolar I disorder using the Screen for Cognitive Impairment in Psychiatry Scale

The purpose of this study was to compare the psychometric properties of the Screen for Cognitive Impairment in Psychiatry (SCIP) when applied to patients diagnosed with schizophrenia (n = 126) or bipolar I disorder (n = 76), and also to compare the cognitive impairment in both samples of patients and a control group (n = 83) using the SCIP and a complete neuropsychological battery. The SCIP is a scale intended to quickly and easily assess cognitive impairment in patients with severe psychiatric disorders. The results showed firstly that, in terms of internal consistency, temporal stability, dimensional structure, and criterion-referenced validity, the SCIP provides reliable and valid scores at an equivalent level in both schizophrenia and bipolar I disorder samples. Secondly, it showed that differential cognitive impairment between the two patient groups occurs only in verbal memory, although the effect size of the difference is small. Finally, compared with the control group, cognitive impairment was present at all levels in both groups of patients using both the SCIP and the neuropsychological battery, which indicates that the SCIP is a good screening tool for cognitive deficits in schizophrenia and bipolar and useful in clinical practice for healthcare professionals.     

Generalisation of fear and avoidance along a semantic continuum

Directly conditioned fear and avoidance readily generalises to dissimilar but conceptually related stimuli. Here, for the first time, we examined the conceptual/semantic generalisation of both fear and avoidance using real words (synonyms). Participants were first exposed to a differential fear conditioning procedure in which one word (e.g., “broth”; CS+) was followed with brief electric shock [unconditioned stimulus (US)] and another was not (e.g., “assist”; CS–). Next, an instrumental conditioning phase taught avoidance in the presence the CS+ but not the CS–. During generalisation testing, synonyms of the CS+ (e.g., “soup”; GCS+) and CS– (e.g., “help”; GCS–) were presented in the absence of shock. Conditioned fear and avoidance, measured via skin conductance responses, behavioural avoidance and US expectancy ratings, generalised to the semantically related, but not to the semantically unrelated, synonyms. Findings have implications for how natural language categories and concepts mediate the expansion of fear and avoidance repertoires in clinical contexts.     

Emotional Valence Precedes Semantic Maturation of Words: A Longitudinal Computational Study of Early Verbal Emotional Anchoring

We present a longitudinal computational study on the connection between emotional and amodal word representations from a developmental perspective. In this study, children's and adult word representations were generated using the latent semantic analysis (LSA) vector space model and Word Maturity methodology. Some children's word representations were used to set a mapping function between amodal and emotional word representations with a neural network model using ratings from 9-year-old children. The neural network was trained and validated in the child semantic space. Then, the resulting neural network was tested with adult word representations using ratings from an adult data set. Samples of 1210 and 5315 words were used in the child and the adult semantic spaces, respectively. Results suggested that the emotional valence of words can be predicted from amodal vector representations even at the child stage, and accurate emotional propagation was found in the adult word vector representations. In this way, different propagative processes were observed in the adult semantic space. These findings highlight a potential mechanism for early verbal emotional anchoring. Moreover, different multiple linear regression and mixed-effect models revealed moderation effects for the performance of the longitudinal computational model. First, words with early maturation and subsequent semantic definition promoted emotional propagation. Second, an interaction effect between age of acquisition and abstractness was found to explain model performance. The theoretical and methodological implications are discussed.     

Psychometric properties of Spanish version of the Mini-Mental Adjustment to Cancer Scale

Background/ObjectiveThe aim of the study was to examine the factor structure and psychometric properties of the Spanish version of the Mini-Mental Adjustment to Cancer Scale (Mini-MAC) in a large sample of patients with non-metastatic, resected cancer.MethodsProspective, observational, multicenter study for which 914 patients were recruited from 15 Spanish hospitals. Exploratory and confirmatory factor analyses, validity and reliability analyses were conducted.ResultsFactor-analytic results indicated a 4-factor structure of the Spanish version of the Mini-MAC. Three subscales have psychometric properties similar to those of Helplessness, Anxious preoccupation, and Cognitive avoidance of the original the Mini-MAC. The Fighting spirit and the Fatalism subscales were combined on the Positive attitude scale. The four factor-derived scale scores exhibited acceptable accuracy for individual measurement purposes, as well as stability over time in test-retest assessments at 6 months. Validity assessments found meaningful relations between the derived scale scores, and Brief Symptom Inventory depression and anxiety scores and Functional Assessment of Chronic Illness Therapy spiritual well-being scores.ConclusionsThe Spanish version of the Mini-MAC provides reliable and valid measures for patients with non-metastatic, resected cancer, and results corroborate the instrument’s cross-cultural validity.