Differential effects of muscarinic receptor blockade in prelimbic cortex on acquisition and memory formation of an odor-reward task

The present experiments determined the consequences of blocking muscarinic cholinergic receptors of the prelimbic (PL) cortex in the acquisition and retention of an odor-reward associative task. Rats underwent a training test (five trials) and a 24-h retention test (two retention trials and two relearning trials). In the first experiment, rats were bilaterally infused with scopolamine (20 or 5 microg/site) prior to training. Although scopolamine rats showed acquisition equivalent to PBS-injected controls, they exhibited weakened performance in the 24-h retention test measured by number of errors. In the second experiment, rats were injected with scopolamine (20 microg/site) immediately or 1 h after training and tested 24 h later. Scopolamine rats injected immediately showed severe amnesia detected in two performance measures (errors and latencies), demonstrating deficits in retention and relearning, whereas those injected 1 h later showed good 24-h test performance, similar to controls. These results suggest that muscarinic transmission in the PL cortex is essential for early memory formation, but not for acquisition, of a rapidly learned odor discrimination task. Findings corroborate the role of acetylcholine in consolidation processes and the participation of muscarinic receptors in olfactory associative tasks.     

Word frequency and predictability effects in reading French: An evaluation of the E-Z Reader model

French readers' eye movements were monitored as they read a passage of text. Initial global analyses of word frequency, accounting for the majority of fixations in the text, revealed a good fit between the observed data and the simulated data from the E-Z Reader 7 model of eye movement control. However, the model did not perform as well on simulations of contextual predictability effects. A subset of 20 controlled words from the passage were used to examine the combined effects of frequency and predictability. Results from the observed data showed main effects of frequency and predictability but no interaction. With certain modifications, the E-Z Reader 7 model was able to adequately simulate the pattern of data. Although the E-Z Reader model successfully accounted for the present data, we believe that further modifications will be necessary in order to better account for data in the literature.     

Glucocorticoid administration into the dorsal striatum [corrected] facilitates memory consolidation of inhibitory avoidance training but not of the context or footshock components

It is well established that glucocorticoid administration into a variety of brain regions facilitates memory consolidation of fear-conditioning tasks, including inhibitory avoidance. The present findings indicate that the natural glucocorticoid corticosterone administered into the dorsal striatum (i.e., caudate nucleus) of male Wistar rats produced dose- and time-dependent enhancement of inhibitory avoidance memory consolidation. However, as assessed with a modified inhibitory avoidance procedure that took place on two sequential days to separate context training from footshock training, corticosterone administration into the dorsal striatum did not enhance memory of either the contextual or aversively motivational aspects of the task.     

Cultural pluralism and prejudice reduction

Predictions derived from models of cultural pluralism and cultural assimilation were tested. Previous research has shown that highlighting differences between ethnic groups, in conjunction with self-focus, can reduce prejudice. The presented research tested the following questions: (a) does highlighting differences function to reduce prejudice between groups that are dissimilar to each other as well as between those that are highly similar, (b) is prejudice reduction due to distinctiveness a function of the lessened ingroup positivity or lessened outgroup negativity, (c) does making distinctiveness salient reduce prejudice toward only the distinctive outgroups or to outgroups more generically, and (d) does the manipulation equally impact African American, Mexican American, Mexican National, and White American participants? Results demonstrated that highlighting differences while simultaneously focusing on the self reduces prejudice, although similarity mediates the relationship with those who are perceived as more different. Distinctiveness also reduced outgroup negativity and generalized to other outgroups. Finally, the manipulation reduced prejudice only for White Americans, Mexican Americans, and Mexican Nationals.     

A comparison of implicit memory tests in schizophrenic patients and normal controls

The objective of the current study was to compare the performance of schizophrenic patients and normal controls on implicit memory tests. Two neuropsychological tasks were administered to 29 patients and normal participant samples. The implicit tests were: Word fragment completion and Word production from semantic categories. The priming score was the variable of interest. Priming effects are obtained in normal subjects and schizophrenia patients, regardless of the implicit test used. However, a dissociation in priming between normal and patient groups was observed, depending on the test used. For word fragment test, priming was identical between the two groups. However, for word production, priming obtained in schizophrenics was lower than priming in normal controls. Results confirm a dissociation effect in implicit memory tests. These results could be explained in the context of the Roediger and Blaxton (1987) distinction between data-driven and conceptually-driven processing. This evidence suggests that a complete neuropsychological assessment of memory in schizophrenia should include different kinds of implicit memory tests (procedural, perceptual, and conceptual tasks).     

Emotional ambivalence in risk behaviors: the case of occasional excessive use of alcohol

The purpose of this paper is to study the differential and complementary role played by the theory of planned behavior (TPB) variables and by participants' emotions when recalling and describing previous experiences of such risk behavior in the prediction of the intention to repeat a risk behavior in the immediate future. We chose the behavior of occasional excessive drinking, a risk behavior characterized by evoking attitudinal ambivalence and eliciting mixed emotions, joy and sadness. The results show that emotional ambivalence is not equivalent to attitudinal ambivalence (whose indexes include that of the affective component), and that this emotional information is relevant for predicting the intention to repeat the risk behavior in the near future, enhancing the prediction of the TPB model.     

Prediction of longevity of volunteer service: a basic alternative proposal

A problem for many organizations is the low continuity of volunteers. Diverse theoretical models have been developed to explain sustained volunteerism, but most of these models have focused on the study of welfare volunteerism and not have verified whether their results could be generalized to other types of volunteerism. In this study, we propose a basic model to explain sustained volunteerism in any type of volunteerism. The aim of this study is to examine this basic model empirically in a sample of socio-assistential volunteers and in a sample of environmental volunteers. For this purpose, 290 volunteers completed a questionnaire and subsequently, two telephone follow-ups were carried out to determine whether the volunteers remained in the NGO one year later. The results show that the basic model offers an acceptable explanation of sustained volunteerism in the two types of volunteer samples studied, but it accounted for a low percentage of variance of the duration of service in both samples. Various relevant implications for the practical management of volunteerism in organizations are derived from theses findings.