Centerscope

Centerscope, formerly Scope, was published by the Boston University Medical Center "to communicate the concern of the Medical Center for the development and maintenance of improved health care in contemporary society.

Centerscope

Centerscope, formerly Scope, was published by the Boston University Medical Center "to communicate the concern of the Medical Center for the development and maintenance of improved health care in contemporary society.

Centerscope

Centerscope, formerly Scope, was published by the Boston University Medical Center "to communicate the concern of the Medical Center for the development and maintenance of improved health care in contemporary society.

SOCIEDADE CIVIL E POLÍTICAS PÚBLICAS PARA JUVENTUDE: UMA NOVA EXPERIÊNCIA

A busca de novos modelos de políticas públicas tem se ampliado devido a participação mais efetiva da sociedade civil. Um desses modelos oriundos da sociedade civil é o consórcio da juventude, integrante do PNPE – Programa Nacional do Primeiro Emprego. A elaboração da política pública pela sociedade civil se dá num momento onde a sociedade civil organizada busca uma participação mais efetiva dentro dos canais organizacionais estabelecidos

Dissociable effects of 5-HT2C receptor antagonism and genetic inactivation on perseverance and learned non-reward in an egocentric spatial reversal task

Cognitive flexibility can be assessed in reversal learning tests, which are sensitive to modulation of 5-HT2C receptor (5-HT2CR) function. Successful performance in these tests depends on at least two dissociable cognitive mechanisms which may separately dissipate associations of previous positive and negative valence. The first is opposed by perseverance and the second by learned non-reward. The current experiments explored the effect of reducing function of the 5-HT2CR on the cognitive mechanisms underlying egocentric reversal learning in the mouse. Experiment 1 used the 5-HT2CR antagonist SB242084 (0.5 mg/kg) in a between-groups serial design and Experiment 2 used 5-HT2CR KO mice in a repeated measures design. Animals initially learned to discriminate between two egocentric turning directions, only one of which was food rewarded (denoted CS+, CS−), in a T- or Y-maze configuration. This was followed by three conditions; (1) Full reversal, where contingencies reversed; (2) Perseverance, where the previous CS+ became CS− and the previous CS− was replaced by a novel CS+; (3) Learned non-reward, where the previous CS− became CS+ and the previous CS+ was replaced by a novel CS-. SB242084 reduced perseverance, observed as a decrease in trials and incorrect responses to criterion, but increased learned non-reward, observed as an increase in trials to criterion. In contrast, 5-HT2CR KO mice showed increased perseverance. 5-HT2CR KO mice also showed retarded egocentric discrimination learning. Neither manipulation of 5-HT2CR function affected performance in the full reversal test. These results are unlikely to be accounted for by increased novelty attraction, as SB242084 failed to affect performance in an unrewarded novelty task. In conclusion, acute 5-HT2CR antagonism and constitutive loss of the 5-HT2CR have opposing effects on perseverance in egocentric reversal learning in mice. It is likely that this difference reflects the broader impact of 5HT2CR loss on the development and maintenance of cognitive function

Motor control in children with ADHD and non-affected siblings: deficits most pronounced using the left hand

Contains fulltext : 52261.pdf (publisher's version ) (Closed access)BACKGROUND: Attention-deficit/hyperactivity disorder (ADHD) is strongly influenced by heritability. Identifying heritable vulnerability traits (endophenotypes) that mark a relatively high risk of developing the disorder can contribute to the identification of risk genes. A fruitful area for the search for such endophenotypes may be motor control in children with ADHD, since the disorder is frequently accompanied by motor problems. METHOD: The current study used a large sample of 350 children with ADHD, 195 non-affected siblings and 271 normal controls aged 5-19 years. Children were administered two computerised motor control tasks in which they had to trace a path between two circles (Tracking task) and follow a randomly moving target (Pursuit task). Both tasks were performed with both the right and the left hand. RESULTS: Children with ADHD were less precise and stable than controls. Non-affected siblings also deviated from controls, but only on the Tracking task. Group differences were modulated by the use of the right versus the left hand: no group differences emerged when the right hand was used, yet group differences did emerge when the left hand was used. Performance on both tasks was significantly familial. CONCLUSIONS: Imprecision and instability of movements in children with ADHD and in their non-affected siblings as measured by the Tracking task might be suitable endophenotypic candidates: these deficits are familially present in children having ADHD as well as in their non-affected siblings. Motor performance might be best assessed in children using their left hand, because motor control deficits are most pronounced using the left hand. This might relate to right hemispheric brain pathology in children with ADHD (and possibly in their non-affected siblings) that is related to the control of the left hand and/or relate to differential effects of daily life practice on both hands, which may be smaller on the left hand

Temporal characteristics of semantic perseverations induced by blocked-cyclic picture naming

When unimpaired participants name pictures quickly, they produce many perseverations that bear a semantic relation to the target, especially when the pictures are blocked by category. Evidence suggests that the temporal properties of these "semantic perseverations" may differ from typical lexical perseverations in aphasia. To explore this, we studied semantic perseverations generated by participants with aphasia on a naming task with semantic blocking [Schnur, T. T., Schwartz, M. F., Brecher, A., & Hodgson, C. (2006). Semantic interference during blocked-cyclic naming: Evidence from aphasia. Journal of Memory and Language, 54, 199-227]. The properties of these perseverations were investigated by analyzing how often they occurred at each lag (distance from prior occurrence) and how time (response-stimulus interval) influenced the lag function. Chance data sets were created by reshuffling stimulus-response pairs in a manner that preserved unique features of the blocking design. We found that the semantic blocking manipulation did not eliminate the expected bias for short-lag perseverations (recency bias). However, immediate (lag 1) perseverations were not invariably the most frequent, which hints at a source of inconsistency within and across studies. Importantly, there was not a reliable difference between the lag functions for perseverations generated with a 5 s, compared to 1 s, responsestimulus interval. The combination of recency bias and insensitivity to elapsed time indicates that the perseveratory impetus in a named response does not passively decay with time but rather is diminished by interference from related trials. We offer an incremental learning account of these findings

Centerscope

Centerscope, formerly Scope, was published by the Boston University Medical Center "to communicate the concern of the Medical Center for the development and maintenance of improved health care in contemporary society.