Reconsolidation of declarative memory in humans

The reconsolidation hypothesis states that a consolidated memory could again become unstable and susceptible to facilitation or impairment for a discrete period of time after a reminder presentation. The phenomenon has been demonstrated in very diverse species and types of memory, including the human procedural memory of a motor skill task but not the human declarative one. Here we provide evidence for both consolidation and reconsolidation in a paired-associate learning (i.e., learning an association between a cue syllable and the respective response syllable). Subjects were given two training sessions with a 24-h interval on distinct verbal material, and afterward, they received at testing two successive retrievals corresponding to the first and second learning, respectively. Two main results are noted. First, the first acquired memory was impaired when a reminder was presented 5 min before the second training (reconsolidation), and also when the second training was given 5 min instead of 24 h after the first one (consolidation). Second, the first retrieval proved to influence negatively on the later one (the retrieval-induced forgetting [RIF] effect), and we used the absence of this RIF effect as a very indicator of the target memory impairment. We consider the demonstration of reconsolidation in human declarative memory as backing the universality of this phenomenon and having potential clinical relevance. On the other hand, we discuss the possibility of using the human declarative memory as a model to address several key topics of the reconsolidation hypothesis.     

Cholinergic activity in the insular cortex is necessary for acquisition and consolidation of contextual memory

Experiences with a high emotional content (aversive) tend to be stored as long-term memories; however, there are also contextual recollections, which form a significant part of our memories. Different research has shown that the insular cortex (IC) plays an important role during aversive memory formation, yet its role during incidental/non-aversive learning like pre-exposure contextual memory formation has received little attention. The objective of this research was to establish the role of cholinergic activity in the IC through its muscarinic receptors during the formation of inhibitory avoidance (IA) memory, as well as during pre-exposure contextual memory, using a paradigm such as latent inhibition (LI). Rats with bilateral cannulae directed into the IC were trained in the LI paradigm of IA or IA task alone. The muscarinic antagonist receptor scopolamine was infused bilaterally into the IC 5 min before the pre-exposure into the dark chamber of the IA cage, one day before the conventional IA training or during the IA training day. During the IA test, the entrance latency into the dark chamber of the IA cage was measured as an index of contextual memory. The results showed that scopolamine infused before and after IA training disrupts inhibitory avoidance memory. Also, it showed that the pre-exposed saline-infused animals (LI) had a lower entrance latency compared to the group not pre-exposed (IA). However, the group that received scopolamine into the IC before, but not after, the pre-exposure to the dark chamber, presented a similar latency to the IA group, showing a blockade of the latent inhibition of the IA. These results suggest that cholinergic activity in the insular cortex is necessary during the acquisition and consolidation of avoidance memory, but appears necessary only during the acquisition of pre-exposure non-aversive contextual memory.     

Electrical stimulation of the pedunculopontine tegmental nucleus in freely moving awake rats: time- and site-specific effects on two-way active avoidance conditioning

The pedunculopontine tegmental nucleus (PPTg) is involved in the regulation of thalamocortical transmission and of several functions related to ventral and dorsal striatal circuits. Stimulation of the PPTg in anesthetized animals increases cortical arousal, cortical acetylcholine release, bursting activity of mesopontine dopaminergic cells, and striatal dopamine release. It was hypothetized that PPTg stimulation could improve learning by enhancing cortical arousal and optimizing the activity of striatal circuits. We tested whether electrical stimulation (ES) of the PPTg, applied to freely-moving awake rats previously implanted with a chronic electrode, would improve the acquisition and/or the retention of two-way active avoidance conditioning, and whether this effect would depend on the specific PPTg region stimulated (anterior vs posterior) and on the time of ES: just before (pre-training) or after (post-training) each of three training sessions. The treatment consisted of 20 min of ES (0.2 ms pulses at 100 Hz; current intensity: 40-80 microA). The results showed that (1) this stimulation did not induce either any signs of distress nor abnormal behaviors, apart from some motor stereotyped behaviors that disappeared when current intensity was lowered; (2) pre-training ES applied to the anterior PPTg improved the acquisition of two-way active avoidance, (3) no learning improvement was found after either post-training ES of the anterior PPTg, or pre- and post-training ES of the posterior PPTg. The results give support to a role of PPTg in learning-related processes, and point to the existence of functional PPTg regions.     

mTOR signaling in the hippocampus is necessary for memory formation

It is widely accepted that the formation of long-term memory (LTM) requires mRNA translation, but little is known about the cellular mechanisms in the brain that regulate this process. Mammalian target of rapamycin (mTOR) is a key regulator of translational efficacy and capacity. Here, we show that LTM formation of one-trial inhibitory avoidance (IA) in rats, a hippocampus-dependent fear-motivated learning task, requires mTOR activation. IA training is specifically associated with a rapid increase in the phosphorylation state of mTOR and its substrate ribosomal S6 kinase (p70S6K). Bilateral intra-CA1 infusion of rapamycin, a selective mTOR inhibitor, 15 min before, but not immediately after training completely hinders IA LTM without affecting short-term memory (STM) retention. Therefore, our findings indicate that the regulation of hippocampal mRNA translation is a major control step in memory consolidation.     

Temperamental dimension and anxiety problems in a clinical sample of three- to six-year old children: a study of variables

In the last few years, many researchers have studied the presence of common dimensions of temperament in subjects with symptoms of anxiety. The aim of this study is to examine the association between temperamental dimensions (high negative affect and activity level) and anxiety problems in clinical preschool children. A total of 38 children, ages 3 to 6 years, from the Infant and Adolescent Mental Health Center of Girona and the Center of Diagnosis and Early Attention of Sabadell and Olot were evaluated by parents and psychologists. Their parents completed several screening scales and, subsequently, clinical child psychopathology professionals carried out diagnostic interviews with children from the sample who presented signs of anxiety. Findings showed that children with high levels of negative affect and low activity level have pronounced symptoms of anxiety. However, children with anxiety disorders do not present different temperament styles from their peers without these pathologies.     

Assessing workplace bullying: Spanish validation of a reduced version of the Negative Acts Questionnaire

The aim of the present study was to validate a reduced Spanish version of the Negative Acts Questionnaire (NAQ; Einarsen & Raknes, 1997). This instrument, which has been widely used in various studies, was developed to measure workplace bullying. Two samples, the first comprising 352 employees from 11 organizations, and the second comprising victims of bullying who were recruited from 15 Spanish associations against bullying, participated in the study. Exploratory factor analysis conducted with the data from the first sample revealed a two-factor solution that accounted for 63.3% of the total variance. The data from the second sample were used for confirmatory factor analyses to compare three structure models of the NAQ (one factor, two independent factors, and two correlated factors). The results indicate that the correlated two-factor model provided the best fit to the data (chi2/df = 2.1, CFI = .93, GFI = .95, RMR = .04, RMSEA = .06, AIC = 215.4). Reliability analysis showed that this 14-item Spanish version had high internal consistency. Significant correlations between the NAQ and its dimensions and diverse health and perceived stress scales were found, which provided evidence of construct validity. Taken conjointly, the results of this study support the use of the Spanish version of the reduced NAQ in future research.     

Impact of parenting styles on adolescents' self-esteem and internalization of values in Spain

The relationship of parenting styles with adolescents' outcomes was analyzed within a sample of Spanish adolescents. A sample of 1456 teenagers from 13 to 16 years of age, of whom 54.3% were females, reported on their parents' child-rearing practices. The teenagers' parents were classified into one of four groups (authoritative, authoritarian, indulgent, or neglectful). The adolescents were then contrasted on two different outcomes: (1) priority given to Schwartz's self-transcendence (universalism and benevolence) and conservation (security, conformity, and tradition) values and (2) level of self-esteem (appraised in five domains: academic, social, emotional, family and physical). The results show that Spanish adolescents from indulgent households have the same or better outcomes than adolescents from authoritative homes. Parenting is related with two self-esteem dimensions--academic and family--and with all the self-transcendence and conservation values. Adolescents of indulgent parents show highest scores in self-esteem whereas adolescents from authoritarian parents obtain the worst results. In contrast, there were no differences between the priority given by adolescents of authoritative and indulgent parents to any of the self-transcendence and conservation values, whereas adolescents of authoritarian and neglectful parents, in general, assign the lowest priority to all of these values.     

Computer speech-based remediation for reading disabilities: the size of spelling-to-sound unit in a transparent orthography

This study was designed to assess the effects of four reading-training procedures for children with reading disabilities (RD) in a transparent orthography, with the aim of examining the effects of different spelling-to-sound units in computer speech-based reading. We selected a sample of 83 Spanish children aged between 7 years 1 month and 10 years 6 months (M = 105.2, SD = 7.8) whose pseudoword reading performance was below the 25th percentile and IQ > 90. The participants were randomly assigned to five groups: (a) the whole-word training group (WW) (n = 17), (b) the syllable training group (S)(n = 16), (c) the onset-rime training group (OR) (n = 17), (d) the phoneme training group (P) (n = 15), and (e) the untrained control group (n = 18). Children were pre- and post-tested in word recognition, reading comprehension, phonological awareness, and orthographic and phonological tasks. The results indicate that experimental groups who participated in the phoneme and syllable conditions improved their word recognition in comparison with the control group. In addition, dyslexics who participated in the phoneme, syllable, and onset-rime conditions made a greater number of requests during computer-based word reading under conditions that required extensive phonological computation (low frequency words and long words). Reading time, however, was greater for long words in the phoneme group during computer-based reading. These results suggest the importance of training phonological processes in improving word decoding in children with dyslexia who learn in a consistent orthography.