Effects of hippocampal lesions in overshadowing and blocking procedures.

The effects of ibotenic acid lesions of the hippocampus on overshadowing and blocking were examined in a Pavlovian appetitive conditioning experiment with rats. In a standard test of performance to the overshadowed or blocked target stimulus, sham-lesioned rats displayed both of these stimulus-selection phenomena. Rats with hippocampal lesions showed normal blocking, but no overshadowing. Subsequent inhibitory learning about the target stimulus was slower after overshadowing or blocking procedures than after a control procedure in sham-lesioned rats, but not in lesioned rats. These results suggest that exposure to these procedures can induce hippocampally mediated losses in conditioned stimulus associability (learning rate parameter), even when those losses are not a major determinant of the stimulus-selection effects themselves. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Social-emotional characteristics of preschool-aged children referred for Child Find screening and assessment: a comparative study

In order to determine changes in breathing patterns brought about by resistive loading, ventilation was recorded in 11 healthy subjects with four linear resistances (3.57, 5.75, 8.76 and 13.13 cmH2O L(-1) sec) added in a random order throughout the entire breath. At steady state, a breath-by-breath analysis of airflow was used to quantify the pattern of breathing in terms of respiratory variables: TI, TE, Tt, VT, VT/TI, TI/Tt, and by taking TI, TE, VT all together (TRIAD) and also the shape of the entire airflow profile quantified by harmonic analysis (ASTER). Group analysis using ANOVA showed significant changes in all variables. There were increasing changes with increasing loads in all variables, the smallest changes being in TI/Tt. Within to between-individual comparisons between two loads showed that only TI/Tt and the ASTER were more similar within than between-individuals for all comparisons. It was concluded that at steady state mechanisms of load compensation come into play inducing changes in the pattern of breathing proportional to the loads while maintaining some of the individual characteristics.     

The influence of CS-US interval on several different indices of learning in appetitive conditioning.

Four experiments examined the effects of varying the conditioned stimulus-unconditioned stimulus (CS-US) interval (and US density) on learning in an appetitive magazine approach task with rats. Learning was assessed with conditioned response (CR) measures, as well as measures of sensory-specific stimulus-outcome associations (Pavlovian-instrumental transfer, potentiated feeding, and US devaluation). The results from these studies indicate that there exists an inverse relation between CS-US interval and magazine approach CRs, but that sensory-specific stimulus-outcome associations are established over a wide range of relatively long, but not short, CS-US intervals. These data suggest that simple CR measures provide different information about what is learned than measures of the specific stimulus-outcome association, and that time is a more critical variable for the former than latter component of learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Specification and Verification using Message Sequence Charts

Message sequence charts is a notation used in practice by protocol designers and system engineers. In this survey, some of the recent results related to this notation, in the context of specification and automatic verification of communication protocols, are presented.     

A longitudinal test of the influence of congruence: Job satisfaction, competency utilization, and counterproductive behavior.

The assumption that congruence between workers and jobs results in job satisfaction is fundamental to vocational theory. Evidence that person–job congruence goes with satisfaction is mixed; correlations are often too small to be of practical value. A hypothesis that interest congruence is more closely linked with job satisfaction for workers with clearly defined interests as opposed to workers with poorly defined interests is tested. Hypotheses about other consequences of person–job incongruence—counterproductive behavior, low job involvement, and turnover—also are tested in a predictive study. The hypothesis that differentiation moderates the relation between congruence and satisfaction and other hypotheses about the consequences of incongruence did not receive support, but the results do imply that congruence is a moderately efficient predictor of satisfaction when between-occupation sources of variance are excluded by the research design. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Amygdala Central Nucleus Function Is Necessary for Learning, but Not Expression, of Conditioned Auditory Orienting.

In Pavlovian appetitive conditioning, rats often acquire 2 classes of conditioned responses: those whose form is determined by the reinforcer, and those whose form is determined by characteristics of the conditioned stimulus (CS). Consistent with the results of previous lesion studies, reversible inactivation of amygdala central nucleus function during pairings of an auditory CS with food prevented the acquisition of conditioned orienting responses specific to auditory CSs, whereas food-related conditioned behaviors were acquired normally. Neither inactivation nor posttraining neurotoxic lesions of the central nucleus affected the expression of previously acquired conditioned orienting. Thus, although the central nucleus is critical to the acquisition of information required for conditioned orienting to auditory cues, it is not needed for maintaining this information for later use. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

In Vitro Selection of a Single-Stranded DNA Molecular Recognition Element against Atrazine

Widespread use of the chlorotriazine herbicide, atrazine, has led to serious environmental and human health consequences. Current methods of detecting atrazine contamination are neither rapid nor cost-effective. In this work, atrazine-specific single-stranded DNA (ssDNA) molecular recognition elements (MRE) were isolated. We utilized a stringent Systematic Evolution of Ligands by Exponential Enrichment (SELEX) methodology that placed the greatest emphasis on what the MRE should not bind to. After twelve rounds of SELEX, an atrazine-specific MRE with high affinity was obtained. The equilibrium dissociation constant (K_d) of the ssDNA sequence is 0.62 ± 0.21 nM. It also has significant selectivity for atrazine over atrazine metabolites and other pesticides found in environmentally similar locations and concentrations. Furthermore, we have detected environmentally relevant atrazine concentrations in river water using this MRE. The strong affinity and selectivity of the selected atrazine-specific ssDNA validated the stringent SELEX methodology and identified a MRE that will be useful for rapid atrazine detection in environmental samples.