Temporal coding in conditioned inhibition: analysis of associative structure of inhibition

Two experiments with rats as subjects were conducted to investigate the associative structure of temporal control of conditioned inhibition through posttraining manipulation of the training excitor-unconditioned stimulus (US) temporal relationship. Experiment 1 found that following simultaneous Pavlovian inhibition training (i.e., A --> US/XA-no US) in which a conditioned stimulus (CS A) was established as a delay excitor, maximal inhibition was observed on a summation test when CS X was compounded with a delay transfer CS. Furthermore, posttraining shifts in the A-US temporal relationship from delay to trace resulted in maximal inhibition of a trace transfer CS. Experiment 2 found complementary results to Experiment 1 with an A-US posttraining shift from serial to simultaneous. These results suggest that temporal control of inhibition is mediated by the training excitor-US temporal relationship.     

Unilateral forced nostril breathing affects dichotic listening for emotional tones

Unilateral forced nostril breathing (UFNB) through the left nostril is associated with enhanced spatial abilities, whereas UFNB through the right nostril is associated with enhanced verbal abilities. However, the effects of UFNB on standard tasks of laterality (e.g., dichotic listening) are unknown. This study employed dichotic listening for word targets, which typically exhibits a right ear advantage (REA), and dichotic listening for emotional targets, which typically exhibits a left ear advantage (LEA). Participants were asked to breathe either through their dominant nostril (congruent UFNB) or to breathe through their non-dominant nostril (incongruent UFNB) for the entire testing session. There was a significant three-way interaction between the type of dichotic listening task, nostril dominance, and nostril assignment, with the expected REA for word targets and the expected LEA for emotional targets-with one exception. Right nostril dominant participants assigned to the congruent condition exhibited an LEA for emotional targets (p < .05). The other three groups exhibited the expected LEA/right hemisphere advantage for the detection of emotional targets and all groups exhibited the expected REA/left hemisphere advantage for detection of word targets. As such, possible bias induced by tactile stimulation of the contralateral face cannot account for these results. Thus, our data are consistent with a selective enhancement of right hemispheric lateralized functions by right nostril UFNB.     

Testing different interpretations for the mistaken belief that rays exit the eyes during vision

Research has shown that children and adults believe that emissions from the eye occur during the act of vision. Such beliefs are similar to ancient extramission theories of perception. In Study 1, the authors tested the idea that extramission beliefs might stem from people's thinking about what might occur during vision as opposed to what is necessary for seeing. Training participants to think about what is necessary for vision, however, had no effect on extramission responses. The results of Study 2 indicated that emphasizing the idea of visual input led to a decline in extramission responses and supported the hypothesis that extramission notions stem from the outer-oriented phenomenology of vision.     

Enhanced retention in the passive-avoidance task by 5-HT(1A) receptor blockade is not associated with increased activity of the central nucleus of the amygdala

The effect of blockade of 5-HT1A receptors was investigated on (1). retention in a mildly aversive passive-avoidance task, and (2). spontaneous single-unit activity of central nucleus of the amygdala (CeA) neurons, a brain site implicated in modulation of retention. Systemic administration of the selective 5-HT1A antagonist NAN-190 immediately after training markedly-and dose-dependently-facilitated retention in the passive-avoidance task; enhanced retention was time-dependent and was not attributable to variations in wattages of shock received by animals. Systemic administration of NAN-190 had mixed effects on spontaneous single-unit activity of CeA neurons recorded extracellularly in vivo; microiontophoretic application of 5-HT, in contrast, consistently and potently suppressed CeA activity. The present findings-that 5-HT1A receptor blockade by NAN-190 (1). enhances retention in the passive-avoidance task, and (2). does not consistently increase spontaneous neuronal activity of the CeA-provide evidence that a serotonergic system tonically inhibits modulation of retention in the passive-avoidance task through activation of the 5-HT1A receptor subtype at brain sites located outside the CeA.     

An interpersonal analysis of pathological personality traits in DSM-5

The proposed changes to the personality disorder section of the Diagnostic and statistical manual of mental disorders (5th ed.) places an increased focus on interpersonal impairment as one of the defining features of personality psychopathology. In addition, a proposed trait model has been offered to provide a means of capturing phenotypic variation on the expression of personality disorder. In this study, the authors subject the proposed DSM-5 traits to interpersonal analysis using the inventory of interpersonal problems-circumplex scales via the structural summary method for circumplex data. DSM-5 traits were consistently associated with generalized interpersonal dysfunction suggesting that they are maladaptive in nature, the majority of traits demonstrated discriminant validity with prototypical and differentiated interpersonal problem profiles, and conformed well to a priori hypothesized associations. These results are discussed in the context of the DSM-5 proposal and contemporary interpersonal theory, with a particular focus on potential areas for expansion of the DSM-5 trait model.     

Rats distinguish between absence of events and lack of evidence in contingency learning

The goal of three experiments was to study whether rats are aware of the difference between absence of events and lack of evidence. We used a Pavlovian extinction paradigm in which lights consistently signaling sucrose were suddenly paired with the absence of sucrose. The crucial manipulation involved the absent outcomes in the extinction phase. Whereas in the Cover conditions, access to the drinking receptacle was blocked by a metal plate, in the No Cover conditions, the drinking receptacle was accessible. The Test phase showed that in the Cover conditions, the measured expectancies of sucrose were clearly at a higher level than in the No Cover conditions. We compare two competing theories potentially explaining the findings. A cognitive theory interprets the observed effect as evidence that the rats were able to understand that the cover blocked informational access to the outcome information, and therefore the changed learning input did not necessarily signify a change of the underlying contingency in the world. An alternative associationist account, renewal theory, might instead explain the relative sparing of extinction in the Cover condition as a consequence of context change. We discuss the merits of both theories as accounts of our data and conclude that the cognitive explanation is in this case preferred.     

An empirical examination of distributional assumptions underlying the relationship between personality disorder symptoms and personality traits

This article examines the relationship between personality disorder (PD) symptoms and personality traits using a variety of distributional assumptions. Prior work in this area relies almost exclusively on linear models that treat PD symptoms as normally distributed and continuous. However, these assumptions rarely hold, and thus the results of prior studies are potentially biased. Here we explore the effect of varying the distributions underlying regression models relating PD symptomatology to personality traits using the initial wave of the Longitudinal Study of Personality Disorders (N = 250; Lenzenweger, 1999), a university-based sample selected to include PD rates resembling epidemiological samples. PD symptoms were regressed on personality traits. The distributions underlying the dependent variable (i.e., PD symptoms) were variously modeled as normally distributed, as counts (Poisson, Negative-Binomial), and with two-part mixture distributions (zero-inflated, hurdle). We found that treating symptoms as normally distributed resulted in violations of model assumptions, that the negative-binomial and hurdle models were empirically equivalent, but that the coefficients achieving significance often differ depending on which part of the mixture distributions are being predicted (i.e., presence vs. severity of PD). Results have implications for how the relationship between normal and abnormal personality is understood. (PsycINFO Database Record (c) 2012 APA, all rights reserved).