A temporally distinct role for group I and group II metabotropic glutamate receptors in object recognition memory

Recognition memory, involving the ability to discriminate between a novel and familiar object, depends on the integrity of the perirhinal cortex (PRH). Glutamate, the main excitatory neurotransmitter in the cortex, is essential for many types of memory processes. Of the subtypes of glutamate receptor, metabotropic receptors (mGluRs) have received less study than NMDA receptors; thus, the reported experiments examined the role of mGluRs in familiarity discrimination in the rat PRH. Experiments 1 and 2 assessed the effects of systemic administration of MPEP, a group I mGluR (specifically mGluR5) antagonist, and/or LY341495, a group II mGluR antagonist, on a spontaneous object novelty preference task. Simultaneous antagonism of both group I and II mGluRs impaired familiarity discrimination following a 24-h but not a 15-min delay, while antagonism of either mGluR subtype alone had no effect at either delay. The impairment was in acquisition, as in Experiment 3 coadministration of MPEP and LY341495 did not affect recognition memory performance when administered either after the sample phase or prior to test. The impairment in long-term recognition memory was mediated by mGluRs in the PRH, as localized intracortical antagonism of group I and II mGluRs also produced a deficit (Experiment 4). No evidence was found for an involvement of group III mGluRs in the acquisition of long-term familiarity discrimination (Experiment 5). These findings establish that glutamatergic neurotransmission in the PRH via group I and II mGluRs is crucial for the acquisition, but not for the consolidation or retrieval of long-term object recognition memory.     

Current status of newborn screening: decision-making about the conditions to include in screening programs

Newborn screening is considered a highly successful public health program that has resulted in the reduction of mortality, mental retardation, and other serious disabilities in thousands of children since the introduction of screening for phenylketonuria (PKU) in the 1960s. Programs are based in state public health departments such that each state independently reaches decisions as to which conditions should be mandated for inclusion in programs, leading to considerable variability among the states as to what is being screened. New technologies and knowledge of the genetics of many conditions have greatly expanded the number of conditions with potential for inclusion in newborn screening.     

Is it impossible to inhibit isoluminant items, or does it simply take longer? Evidence from preview search

Visual search can be facilitated when participants receive a preview of half the distractors (the preview benefit in search; Watson & Humphreys, 1997). Donk and Theeuwes (2001) have argued that preview-based benefits are abolished if the display items are isoluminant to a background. This is consistent with the preview benefit being due to onset capture by the new stimuli. In contrast, the present experiments challenge this suggestion and show that preview benefits can occur under isoluminant conditions, providing that they are given enough time to occur. In Experiment 1, we showed that a preview benefit can occur even with isoluminant stimuli, provided that the old items are previewed for a sufficient time. In Experiment 2, we tested and rejected the idea that this advantage is due to low-level sensory fatigue for the preview stimuli. These findings indicate that the preview effect is not caused solely by onset capture.     

The relationship of neuronal activity within the sensori-motor region of the subthalamic nucleus to speech

Microelectrode recordings of human sensori-motor subthalamic neuronal activity during spoken sentence and syllable-repetition tasks provided an opportunity to evaluate the relationship between changes in neuronal activities and specific aspects of these vocal behaviors. Observed patterns of neuronal activity included a build up of activity in anticipation of the start of the utterance, a marked reduction in activity associated with the start of the utterance, and a burst of activity during the course of the sentence between the noun phrase and the verb phrase. Overall, changes of neuronal activity were more robust for the sentence repetition task. These data suggest that the basal ganglia play a role in generating meaningful speech utterances, which may parallel its role in complex sequential limb movements. It is possible that the basal ganglia play a role in generating the syntactical structure of language.     

Testing the semantic differential as a model of task processes with the implicit association test

In this study, we examined the hypothesis that semantic judgment tasks share overlapping processes if they require processing on common dimensions but not if they require processing on orthogonal dimensions in semantic space (Osgood, Suci, & Tannenbaum, 1957). We tested the hypothesis with the implicit association test (IATl Greenwald, McGhee, & Schwartz, 1998) in three experiments. Consistent with the hypothesis, IAT effects (costs in reaction time because of incompatible response mapping between associated judgment tasks) occurred consistently when judgment tasks tapped into common semantic dimensions, whereas no IAT effect appeared when judgment tasks entailed processing on orthogonal semantic dimensions.     

Comparative analysis of integrative self-knowledge, mindfulness, and private self-consciousness in predicting responses to stress in Iran

Previous research has established that awareness of self-experience is a stress resistance resource. The present study conducted an analysis of measures that record different aspects of self-awareness (private self-consciousness, mindfulness, and integrative self-knowledge) to explain this stress-resistance effect in a sample of Iranian university students (N = 186). These students responded to Mindfulness Attention Awareness, Private Self-Consciousness, Integrative Self-Knowledge, and Perceived Stress Scales just before the stress of a 20-day final examination period, and they then responded to Symptom Checklist and Vitality measures at four-day intervals during the final examinations. Prior to final examinations, the three self-awareness variables correlated positively with each other and negatively with perceived stress. Regression analyses of the data obtained during final examinations identified mindfulness to be a better operationalization of this stress-resistance resource than private self-consciousness. Specifically, mindfulness but not private self-consciousness was a positive predictor of vitality and a negative predictor of symptoms. Hierarchical regression analyses also demonstrated that mindfulness and integrative self-knowledge both explained resistance to physical symptoms, while integrative self-knowledge functioned as a protective factor toward one's vitality. These data confirm the positive impact that self-awareness has during stress and highlight the importance of considering both mindfulness and integrative self-knowledge in understanding stress-resistance processes.     

Elements Influencing Peer Evaluation: An Examination of Individual Characteristics,Academic Performance,and Collaborative Processes

Collaborative learning has existed for some time, and instructional methods have been developed, such as cooperative learning, team learning, and problem‐based learning. The purpose of this study is to observe students in learning teams and how their observations of their team and team members are reflected in peer evaluations. We examine pre‐ and post‐team history elements, such as basic demographics, personality factors, exam scores, and observations of team process and team goal attainment. Pre‐ and post‐team history factors correlate with peer evaluations and are discussed. In our analyses, we take into account intraclass correlations and individual and group effects. Suggestions are given for future research.