5-HT1a receptor antagonists block perforant path-dentate LTP induced in novel, but not familiar, environments

Numerous studies suggest roles for monoamines in modulating long-term potentiation (LTP). Previously, we reported that both induction and maintenance of perforant path-dentate gyrus LTP is enhanced when induced while animals explore novel environments. Here we investigate the contribution of serotonin and 5-HT1a receptors to the novelty-mediated enhancement of LTP. In freely moving animals, systemic administration of the selective 5-HT1a antagonist WAY-100635 (WAY) attenuated LTP in a dose-dependent manner when LTP was induced while animals explored novel cages. In contrast, LTP was completely unaffected by WAY when induced in familiar environments. LTP was also blocked in anesthetized animals by direct application of WAY to the dentate gyrus, but not to the median raphe nucleus (MRN), suggesting the effect of systemic WAY is mediated by a block of dentate 5-HT1a receptors. Paradoxically, systemic administration of the 5-HT1a agonist 8-OH-DPAT also attenuated LTP. This attenuation was mimicked in anesthetized animals following application of 8-OH-DPAT to the MRN, but not the dentate gyrus. In addition, application of a 5-HT1a agonist to the dentate gyrus reduced somatic GABAergic inhibition. Because serotonergic projections from the MRN terminate on dentate inhibitory interneurons, these data suggest 5-HT1a receptors contribute to LTP induction via inhibition of GABAergic interneurons. Moreover, activation of raphe 5-HT1a autoreceptors, which inhibits serotonin release, attenuated LTP induction even in familiar environments. This suggests that serotonin normally contributes to dentate LTP induction in a variety of behavioral states. Together, these data suggest that serotonin and dentate 5-HT1a receptors play a permissive role in dentate LTP induction, particularly in novel conditions, and presumably, during the encoding of novel, hippocampus-relevant information.     

Input control processes in rapid serial visual presentations: target selection and distractor inhibition

The attentional blink refers to the finding that the 2nd of 2 targets embedded in a stream of rapidly presented distractors is often missed. Whereas most theories of the attentional blink focus on limited-capacity processes that occur after target selection, the present work investigates the selection process itself. Identifying a target letter caused an attentional blink for the enumeration of subsequent dot patterns, but this blink was reduced when the dots shared their color with the target letter. In contrast, performance worsened when the color of the dots matched that of the remaining distractors in the stream. Similarity between the targets also affected competition between different sets of dots presented simultaneously within a single display. The authors conclude that the selection of targets from a rapid serial visual presentation stream is mediated by both excitatory and inhibitory attentional control mechanisms.     

Aging and enumeration: a selective deficit for the subitization of targets among distractors

The term subitization has been used to refer to the fast and accurate enumeration of up to about 4 items. Beyond 4 items, enumeration becomes more serial and less accurate, with each additional item adding to the total enumeration time. The effects of aging on visual enumeration of targets (Os) were assessed with and without the presence of distractors (Xs). Young participants (n = 30; 18-27 years) showed the usual subitization-counting enumeration function, both with and without the presence of distractors. In contrast, for older participants (n = 35; 65-79 years), evidence for subitization was found only when distractors were absent. This occurred even though they could detect an individual target among distractors in parallel across the field. The results are discussed in relation to recent theories of visual selection and enumeration.     

The effects of affirmative action on male-female relationships among African Americans

This article focuses on the little-discussed issue of the impact of affirmative action on black male-female dynamics and interpersonal relationships. Three decades of civil rights campaigns, including often-controversial affirmative action policies, have produced several unanticipated consequences, one of the most crucial being the great disparity between African American males and females in social and economic advancement. While black women have achieved, black men have fallen behind, in part due to the subtle racism of affirmative action implementation. Using fantasy to search for new truths and better directions, the article presents a fictionalized account of the devastating effect of this disparity on African American women. Black women's reactions to the allegorical symbolism of the Twenty-Seventh Year Syndrome are dealt with in the article, and become the basis for reconsidering the message of the Chronicle and enlarging upon its meaning for black male-female relationships, and for the future of affirmative action and other programs of racial uplift.     

Beyond the articulatory loop: A semantic contribution to serial order recall of subspan lists

In two experiments, serial order recall of short lists of content and function words under quiet and articulatory suppression conditions was examined in order to assess the hypotheses that (1) semantic attributes of words contribute to short-term-memory performance, and (2) do soindependently of effects attributable to the articulatory loop component. In Experiment 1, content words were better recalled than function words; both word types were equally impaired by suppression. This provides support for the notion that semantic coding makes an independent contribution to span performance. This word-class effect disappeared in Experiment 2, when content and function words were matched for imageability. These data suggest that at least some aspects of meaning contribute to serial order recall performance for short lists, independently of the articulatory loop.     

When do nonwords activate semantics? Implications for models of visual word recognition

Three lexical decision experiments examined the conditions in which nonwords activate semantics. Lexical decisions to targets (e.g., CAT) were faster when preceded by semantically related nonword primes (e.g., DEG derived from DOG) when the prime was brief and masked; this nonword priming effect was eliminated when the prime was presented for a longer duration. These results are discussed in the context of both parallel distributed processing models and the idea that the occurrence of nonword priming depends upon subjects being unable to verify the identity of the prime.     

Balancing connectedness and self-protection goals in close relationships: a levels-of-processing perspective on risk regulation

A model of risk regulation is proposed to explain how low and high self-esteem people balance the tension between self-protection and connectedness goals in romantic relationships. This model assumes that interpersonal risk automatically activates connectedness and self-protection goals. The activation of these competing goals then triggers an executive control system that resolves this goal conflict. One correlational study and 8 experiments manipulating risk, goal strength, and executive strength and then measuring implicit and explicit goal activation and execution strongly supported the model. For people high in self-esteem, risk triggers a control system that directs them toward the situations of dependence within their relationship that can fulfill connectedness goals. For people low in self-esteem, however, the activation of connectedness goals triggers a control system that prioritizes self-protection goals and directs them away from situations where they need to trust or depend on their partner.     

Proximal Norms,Selected Sociodemographics,and Drinking Behavior Among University Student Athletes

Few studies have examined social norm theory with subpopulations of college students. In this study, the authors examined the relationships between social norms and student‐athlete drinking. Results suggest drinking is a function of proximal norms, particularly related to teammates. Implications for counselor interventions are discussed.     

Word-learning performance in beginning readers.

This investigation examined word-learning performance in beginning readers. The children learned to read words with regular spelling-sound mappings (e.g., snake) more easily than words with irregular spelling-sound mappings (e.g., sword). In addition, there was an effect of semantics: Children learned to read concrete words (e.g., elbow) more successfully than abstract words (e.g., temper). Trial-by-trial learning indicated that children made greater use of the regularity and semantic properties at later trials as compared with early trials. The influence of cognitive skills (paired associate learning and phonological awareness) on word-learning performance was also examined. Regression analyses revealed that whereas paired associate learning skills accounted for unique variance in the children's learning of both regular and irregular words, phonological awareness accounted for unique variance only in the acquisition of regular words.     

Top-down effects of semantic knowledge in visual search are modulated by cognitive but not perceptual load

Moores, Laiti, and Chelazzi (2003) found semantic interference from associate competitors during visual object search, demonstrating the existence of top-down semantic influences on the deployment of attention to objects. We examined whether effects of semantically related competitors (same-category members or associates) interacted with the effects of perceptual or cognitive load. We failed to find any interaction between competitor effects and perceptual load. However, the competitor effects increased significantly when participants were asked to retain one or five digits in memory throughout the search task. Analyses of eye movements and viewing times showed that a cognitive load did not affect the initial allocation of attention but rather the time it took participants to accept or reject an object as the target. We discuss the implications of our findings for theories of conceptual short-term memory and visual attention.