Stability of recent and remote contextual fear memory

Following initial encoding, memories undergo a prolonged period of reorganization. While such reorganization may occur in many different memory systems, its purpose is not clear. Previously, we have shown that recall of recent contextual fear memories engages the dorsal hippocampus (dHPC). In contrast, recall of remote contextual fear memories engages a number of different cortical regions, including the anterior cingulate cortex (ACC). To examine whether this reorganization leads to greater memory stability, we examined reconsolidation of 1 d-old (recent) and 36 d-old (remote) contextual fear memory in mice. We infused the protein synthesis inhibitor, anisomycin (ANI), into either the dHPC or ACC immediately following retrieval of either a recent or remote contextual fear memory. In the dHPC, ANI infusions disrupted subsequent expression of recent, but not remote, contextual fear memory. Similar infusions into the ACC had no effect on either recent or remote contextual fear memories, whereas systemically applied ANI blocked subsequent remote memory expression when long re-exposure durations were used. Together, these data suggest that as memories mature they become increasingly stable. Furthermore, the dissociation between the effects of systemically and centrally administered ANI on remote memory suggests that stability is due, in part, to the distributed nature of remote contextual fear memories.     

Inducing a Rule in Wason's 2-4-6 Task: A Test of the Information-Quantity and Goal-Complementarity Hypotheses

In the standard 2-4-6 induction task, subjects are instructed to discover the rule generating sequences of three numbers by inventing number triples for which they receive immediate feedback. The rule is “ascending numbers”. Performance is greatly aided with Dual Goal (DG) instructions that ask subjects to discover two rules, one that generates “Dax” triples (equivalent to “yes” instances with Single Goal [SG] instructions) and another that generates “Med” triples (equivalent to “no” instances). The present study eliminates two explanations for this effect suggested by Wharton, Cheng, and Wickens (1993). Experiment 1 tested their Information-Quantity hypothesis that the effect results simply from the DG subjects testing more triples prior to proposing a rule. Our DG subjects were more likely to solve the problem and produced more “negative” triples than SG subjects when both groups generated exactly 15 triples. Two further groups received feedback only after generating all 15 triples, and again DG subjects were more likely to solve the problem and to generate more “negative” triples. Experiment 2 tested Wharton et al.'s Goal-Complementarity hypothesis that success under DG instructions hinges on preserving the complementary representation of the two rules. We compared SG instructions with three types of DG instructions that suggested different types of triples (Dax, Med, both Dax and Med, neither Dax nor Med). DG instructions were more effective in promoting successful rule discovery regardless of differences in rule complementarity. Our analysis of the heterogeneity of the examplars generated with DG instructions in both experiments suggest that success on the 2-4-6 task is as much a consequence of the breadth of hypotheses that subjects entertain as it is a consequence of the testing strategy.     

Presymptomatic Testing for Neurogenetic Diseases in Brazil: Assessing Who Seeks and Who Follows through with Testing

Diagnostic tests are available to detect several mutations related to adult-onset, autosomal dominant, neurodegenerative diseases. We aimed to describe our experience in a presymptomatic testing program run by the Brazilian Public Health System from 1999 to 2009. A total of 184 individuals were eligible for presymptomatic testing due to a risk for spinocerebellar ataxia (SCA) - SCA3 (80%), Huntington’s disease (11.9%), familial amyloidotic neuropathy (4.3%), SCA1, SCA2, SCA6, or SCA7. Most were women (70%), married (54%), and had children prior to presymptomatic testing (67%). Their mean age at entrance was 34 (SD = 11 years). Educational level was above the average Brazilian standard. After receipt of genetic counseling, 100 individuals (54%) decided to undergo testing; of these, 51 were carriers. Since no individual returned for post-test psychological evaluation, we conducted a subsequent survey, unrelated to test disclosures. We contacted 57 individuals of whom 31 agreed to participate (24 had been tested, 7 had not). Several ascertainment concerns relating to these numerous losses prevented us from generalizing our results from this second survey. We concluded that: decision-making regarding presymptomatic testing seems to be genuinely autonomous, since after genetic counseling half the individuals who asked for presymptomatic testing decided in favor and half decided against it; general characteristics of Brazilians who sought presymptomatic testing were similar to many European samples studied previously; and individuals at risk for SCA3 may be at greater risk of depression. Although no clear-cut reason emerged for rejection of follow-up psychological sessions after presymptomatic testing, this finding suggests adjustments to our presymptomatic testing program are necessary.     

Validating Regulatory Sensory Processing Disorders Using the Sensory Profile and Child Behavior Checklist (CBCL 1?–5)

The objective was to validate Regulatory Sensory Processing Disorders’ criteria (DC:0-3R, 2005) using empirical data on the presence and severity of sensory modulation deficits and specific psychiatric symptoms in clinical samples. Sixty toddlers who attended a child mental health unit were diagnosed by a clinical team. The following two groups were created: toddlers with RSPD (N?=?14) and those with “other diagnoses in Axis I/II of the DC:0-3R″(OD3R) (N?=?46). Independently of the clinical process, parents completed the Infant Toddler Sensory Profile (as a checklist for sensory symptoms) and the Achenbach Behavior Checklist for ages 1?–5 (CBCL 1?–5). The scores from the two groups were compared. The results showed the following for the RSPD group: a higher number of affected sensory areas and patterns than in the OD3R group; a higher percentage of sensory deficits in specific sensory categories; and a higher severity of behavioral symptoms such as withdrawal, inattention, other externalizing problems and pervasive developmental problems in CBCL 1?–5. The results confirmed our hypotheses by indicating a higher severity of sensory symptoms and identifying specific behavioral problems in children with RSPD. The results revealed convergent validity between the instruments and the diagnostic criteria for RSPD and supported the validity of RSPD as a unique diagnosis. The findings also suggested the importance of identifying sensory modulation deficits in order to develop an early intervention to enhance the sensory capacities of children who do not fully satisfy the criteria for some DSM-IV-TR disorders.     

Auditory contagious yawning in domestic dogs (Canis familiaris): first evidence for social modulation

Dogs' capacity to 'catch' human yawns has recently attracted the attention of researchers in the field of animal cognition. Following recent studies suggesting that contagion yawning in humans, and some other primates, is empathy-related, some authors have considered the possibility that the same mechanism may underlie contagious yawning in dogs. To date, however, no positive evidence has been found, and more parsimonious hypotheses have been put forward. The present study explored the 'contagion-only' hypothesis by testing whether the mere sound of a human yawn can be sufficient to elicit yawning in dogs, in a way that is unaffected by social-emotional factors. Unexpectedly, results showed an interesting interplay between contagion and social effects. Not only were dogs found to catch human yawns, but they were also found to yawn more at familiar than unfamiliar yawns. Although not allowing for conclusive inferences about the mechanisms underlying contagious yawning in dogs, this study provides first data that renders plausible empathy-based, emotionally connected, contagious yawning in these animals.     

Symmetry axiom of Haken–Kelso–Bunz coordination dynamics revisited in the context of cognitive activity

We present an axiomatic derivation of a model proposed by Haken, Kelso, and Bunz (1985) that describes dynamical aspects of the rhythmic coordination between two limbs. Elaboration of this model has included a symmetry parameter that captures the coordination consequences of an inherent or imposed frequency difference between the limbs. We modified one of the axioms involved in the model derivation, a symmetry axiom, in order to incorporate a new symmetry parameter. This new parameter defines a shift between (a) the laboratory coordinate system, in which the behavior is observed, and (b) a second, postulated coordinate system. It is this second coordinate system, in which the relevant state dynamics is assumed to take place and in which the state dynamics evolves under the impact of an attractor. The state dynamics as described in the attractor coordinate system is then mapped by means of the new symmetry parameter to the laboratory coordinate system. We discuss analytically the bifurcation diagram of the model and determine main effects and interaction effects of manipulations related to the symmetry parameters and related to the mode of coordination (in-phase and anti-phase). The theoretical results are brought to bear on the challenging experimental observation that concurrent cognitive activity (counting, encoding, retrieving, sentence analysis) changes the location of the bimanual coordination attractor but not its strength. The theoretical results suggest that cognitive activity may have the effect it has because it shifts the attractor coordinate system relative to the laboratory coordinate system.     

Indiscriminate behavior observed in the strange situation among institutionalized toddlers: Relations to caregiver report and to early family risk

Socially disinhibited or indiscriminate behavior (IB) has traditionally been investigated using caregiver reports. More recently, an observational measure based on the Strange Situation Procedure (M. Ainsworth, M. Blehar, E. Waters, & S. Wall, 1978), the Rating of Infant and Stranger Engagement (RISE; C. Riley, A. Atlas‐Corbett, & K. Lyons‐Ruth, 2005), was validated in home‐reared at‐risk children. The present study aimed to validate the RISE in an institutionally reared sample using the caregiver report, to assess whether IB assessed with the RISE was elevated among the institutionalized children, and to explore potential risk factors associated with IB. The study was conducted among 74 institutionalized toddlers aged 11 to 30 months. Sociodemographic questionnaires were used to assess pre‐admission experiences, and aspects of institutional placement were coded from the children's files in the institution and staff's report. Institutionalized children displayed high frequencies of IB as assessed on the RISE, and this instrument was validated against caregiver report. Pre‐admission experiences of the institutionalized children in their biological families—namely, prenatal risk and maternal emotional neglect risk—predicted IB. Results suggest that the RISE is adequate to use among institutionally reared toddlers and point to aspects of the early familial environment that may be implicated in IB.     

A Tutorial and Case Study in Propensity Score Analysis: An Application to Estimating the Effect of In-Hospital Smoking Cessation Counseling on Mortality

Propensity score methods allow investigators to estimate causal treatment effects using observational or nonrandomized data. In this article we provide a practical illustration of the appropriate steps in conducting propensity score analyses. For illustrative purposes, we use a sample of current smokers who were discharged alive after being hospitalized with a diagnosis of acute myocardial infarction. The exposure of interest was receipt of smoking cessation counseling prior to hospital discharge and the outcome was mortality with 3 years of hospital discharge. We illustrate the following concepts: first, how to specify the propensity score model; second, how to match treated and untreated participants on the propensity score; third, how to compare the similarity of baseline characteristics between treated and untreated participants after stratifying on the propensity score, in a sample matched on the propensity score, or in a sample weighted by the inverse probability of treatment; fourth, how to estimate the effect of treatment on outcomes when using propensity score matching, stratification on the propensity score, inverse probability of treatment weighting using the propensity score, or covariate adjustment using the propensity score. Finally, we compare the results of the propensity score analyses with those obtained using conventional regression adjustment.     

Parental Marital Discord and Treatment Response in Depressed Adolescents

Evidence suggests that parental marital discord contributes to the development of internalizing and externalizing symptoms in children and adolescents. Few studies, however, have examined the association between parental marital discord and youth’s response to treatment. The present study examined the impact of interparental discord on treatment response in a randomized control trial of adolescents with major depression enrolled in the Treatment for Adolescents with Depression Study (TADS). Participants were 260 adolescents from two-parent households randomly assigned to one of four treatment groups: fluoxetine (FLX), cognitive behavior therapy (CBT), their combination (COMB), or placebo (PBO). Logistic regressions revealed that parental marital discord interacted with youth gender and co-morbid oppositionality symptoms to predict group differences in treatment response.