Bilateral lesion of the cerebellar-dentate nucleus impairs egocentric sequential learning but not egocentric navigation in the rat

The involvement of the cerebellum in procedural learning is demonstrated in visuomotor-sequence tasks, as lesion of this area impedes the acquisition of new sequences. Likewise, the lateral cerebellum appears to be involved in the acquisition of new sequences, but not in the execution of learned sequences. In contrast, the dentate nucleus participates only in the execution of learned visuomotor sequences. In previous studies, disruption of the procedural elements of spatial navigation following cerebellar or dentate lesions has been reported. However, as praxic strategies (egocentric learning) are included in the procedural elements of the navigation, the participation of the cerebellar-dentate nucleus in egocentric procedural learning processes has not been evaluated. Therefore, using colchicine, bilateral lesions were made in the cerebellar-dentate nucleus of Sprague-Dawley rats, and these rats were given two tasks: egocentric-based motor sequence learning in the radial maze and egocentric navigation in the Morris water maze. The lesioned rats were unable to use the sequential information in the short term and showed delayed long-term acquisition, which was probably due to the inability to detect the sequence. No effects on the egocentric navigation task were observed. Our results indicate that the cerebellar-dentate nucleus is involved in the detection of egocentric sequential information but not in the use of this information in the navigation process. Further, they show differential involvement of the cerebellar-dentate nucleus in the execution of learned visuomotor sequences, as the dentate lesion disrupted the acquisition of new egocentric-motor-based sequences.     

Multistable syllables as enacted percepts: a source of an asymmetric bias in the verbal transformation effect

Perceptual changes are experienced during rapid and continuous repetition of a speech form, leading to an auditory illusion known as the verbal transformation effect. Although verbal transformations are considered to reflect mainly the perceptual organization and interpretation of speech, the present study was designed to test whether or not speech production constraints may participate in the emergence of verbal representations. With this goal in mind, we examined whether variations in the articulatory cohesion of repeated nonsense words--specifically, temporal relationships between articulatory events--could lead to perceptual asymmetries in verbal transformations. The first experiment displayed variations in timing relations between two consonantal gestures embedded in various nonsense syllables in a repetitive speech production task. In the second experiment, French participants repeatedly uttered these syllables while searching for verbal transformation. Syllable transformation frequencies followed the temporal clustering between consonantal gestures: The more synchronized the gestures, the more stable and attractive the syllable. In the third experiment, which involved a covert repetition mode, the pattern was maintained without external speech movements. However, when a purely perceptual condition was used in a fourth experiment, the previously observed perceptual asymmetries of verbal transformations disappeared. These experiments demonstrate the existence of an asymmetric bias in the verbal transformation effect linked to articulatory control constraints. The persistence of this effect from an overt to a covert repetition procedure provides evidence that articulatory stability constraints originating from the action system may be involved in auditory imagery. The absence of the asymmetric bias during a purely auditory procedure rules out perceptual mechanisms as a possible explanation of the observed asymmetries.     

Recruitment of first-generation Latinos in a rural community: the essential nature of personal contact

The purpose of this article is to report on the success of various recruitment activities for a behavioral observation study with Spanish-speaking Latino families in a rural community in the western United States. Recruitment activities are pivotal to research to research because the enormous impact to the quality of the sample and, thus, the quality of the answers to the questions posed by the research. Recruitment can be especially challenging for researchers working with ethnic minorities due to a historical legacy of mistreatment by researchers that has led to healthy reticence to participate in research investigations. The present research presented unique challenges in that the data collection (1) took place in a rural community, (2) sought participation of a recent immigrant population, and (3) required videotaping. Data were collected from 50 families in a western rural community. After multiple recruitment strategies were used, the research team learned that word of mouth and use of existing community resources were the most powerful recruitment strategies. However, participant reports suggest that the other recruitment strategies helped familiarize participants with the study and potentially strengthened the influence of word of mouth referrals. Important differences were found between the easy-to-recruit and the hard-to-recruit samples within this study that support engagement in multiple recruitment strategies.     

Reading strategies and prior knowledge in learning from hypertext

In two experiments, we identified two main strategies followed by hypertext readers in selecting their reading orders. The first consisted in selecting the text semantically related to the previously read section (coherence strategy), and the second in choosing the most interesting text, delaying reading of less interesting sections (interest strategy). Comprehension data revealed that these strategies affected learning differently as a function of the reader's prior knowledge. For low-knowledge readers, the coherence strategy supported better learning of the content. This effect seems to rely on the improvement of reading order coherence induced by this strategy. By contrast, for intermediate-knowledge readers the coherence and the interest strategies benefited comprehension equally. In both cases, learning was supported through the active processing induced by these strategies. Discussion focuses on resolving inconsistencies in the literature concerning whether or not hypertext supports better comprehension than does traditional linear texts.     

Importance-Performance Analysis for services management

Importance-Performance Analysis (IPA) constitutes an indirect approximation to user's satisfaction measurement that allows to represent, in an easy and functional way, the main points and improvement areas of a specific product or service. Beginning from the importance and judgements concerning the performance that users grant to each prominent attributes of a service, it is possible to obtain a graphic divided into four quadrants in which recommendations for the organization economic resources management are included. Nevertheless, this tool has raised controversies since its origins, referred fundamentally to the placement of the axes that define the quadrants and the conception and measurement of the importance of attributes that compose the service. The primary goal of this article is to propose an alternative to the IPA representation that allows to overcome the limitations and contradictions derived from the original technique, without rejecting the classical graph. The analysis applies to data obtained in a survey about satisfaction with primary health care services of Galicia. Results will permit to advise to primary health care managers with a view toward the planning of future strategic actions.     

Quality service in supermarkets: a proposal of measurement

This assignment has the aim of going deeply into the study of service quality perception in supermarkets. The research tries to find the criterion used when rating the services received in a supermarket and also to elaborate an instrument to measure the service quality in this context. From the review of the existing bibliography, four theoretical factors and a thirteen items scale have been composed. These four factors are: price, product, service and image and fresh product. In order to check the psychometrical properties of the questionnaire we carried out a computer assisted telephone interviewing (CATI) with a sample of 300 interviews. The results obtained allow us to show a scale with a factorial structure of 4 dimensions that throws up optimal indexes of reliability and validity. At the same time we conclude that the variable called establishment global rate is an important variable in the perceptive structure of the consumers.     

What works for serious juvenile offenders? A systematic review

This study examines the outcomes of best available empirical research regarding the effectiveness of treatment programs implemented in secure corrections to prevent the recidivism of serious (violent and chronic) juvenile offenders (from 12 to 21 years old). In this review 30 experimental and quasi-experimental studies are analyzed, comparing 2831 juveniles in the treatment groups and 3002 youths for the control groups. The global effect size of these 30 studies in terms of standardized mean difference was d = 0.14 in favour of the treatment groups. This size effect, in terms of "r" coefficient reached the value of 0.07, of low magnitude. The cognitive-behavioral methods of treatment were the most effective in decreasing recidivism. These results report that the rehabilitation programs for serious offenders achieve to reduce the general recidivism in comparison with the control juveniles in approximately seven percent.     

A training program to improve the memory of children with Down's syndrome

This study starts out from the general agreement about the explicit memory deficits in children with Down's syndrome. Our aim is to explore the possibilities of the computer as a valuable instrument with which to train memory by teaching cognitive rehearsal strategies. The sample was made up of 40 students with Down's syndrome and was divided into two research groups: control and experimental. The results show a clear tendency towards memory improvement in the experimental group. These results can be considered indicators of the effectiveness of the intervention. They are also very interesting for education, in the sense that teachers can help the students with Down's syndrome to improve their memory capacity.     

Treatment of children with ADHD: psychopedagogical program at school versus psychostimulant medication

This study examined the impact of medication management compared to a psycho-educational program on parent and teacher ratings of children with combined type ADHD. The study lasted 14 weeks and included 50 children. 17 children took medication, 17 received psycho-educational intervention, and 16 children were assigned to the control group. The measures used were the IOWA Conners Scale, the School Problem Inventory, the Abbreviated Conners, and the DSM-IV Inattention-Disorganization and Hyperactivity-Impulsivity rating scales. Regarding teacher ratings, improvements were observed on: a) inattention and school problems in the medication group versus the control group; and b) hyperactivity symptoms in the psycho-pedagogical group versus the control and medication groups. Regarding to parent ratings, improvements were observed on: a)inattention in the psycho-pedagogical group versus the control and medication groups; and b) hyperactivity symptoms in the psycho-pedagogical group versus the control and the medication groups.     

Effects of increasing cognitive load on sustained attention tasks in schizophrenic disorders and schizotypy

In this study we analyze the attentional performance using different cognitive load attentional tasks: low-load cognition (0-CPT) and high-load cognition (DS-CPT). Participants were a group of schizophrenic patients and two groups of normal population psychometrically classified as low schizotypy and high schizotypy according to the SPQ. Our results show that schizophrenic patients were more sensitive to increments on cognitive load, being their attentional performace worse than the rest of the groups. The lack of significant findings in vigilance on the schizotypal traits group is discussed in terms of conceptual and methodological issues about the utility of psychometric strategies to identify vulnerable populations within the spectrum of the schizophrenic disorders.