Perfil desenvolvimental das funções executivas em crianças de 05 a 08 anos da cidade de Natal - RN

This study aimed to establish the developmental profile of executives components in typical child development. This is a correlational cross-sectional study of predominantly quantitative. The instruments for data collection are the subtests included in the NEPSY-II Attention and Executive Functioning domain. Eighty children between 5 and 8 years of age, of both genders, students from public and private schools in the city of Natal were evaluated. The sample was divided into six-month intervals for subsequent analysis of strategies and types of errors. Analysis of variance (univariate and multivariate) and Tukey and Games-Howell post hoc tests were conducted to verify the effect of age on test performance. Subsequent correlations indicate the strength and direction of the relationship between variables. Were identified two peaks of development in the six-month interval adopted for the skills of selective attention and inhibitory control. The results indicate that there’s no significant influence of sex and type of school on the performance of the sample. The performance of preschool children (5 and 6 years) was lower than the other subgroups in most tests. Highlights the role of autoregulation discourse among preschool children during activities of greater executive demand and the abstraction resource as a resolution strategy between the older. Were identified similar development trajectories among selective attention abilities and inhibitory control. In general, there is a decrease in the number of mistakes and increase of success with the age progression. Future longitudinal research can extend the age range encompassed in this study, investigating the developmental course of executive abilities.

A relação entre transtorno da insônia e funções executivas em adultos

The insomnia disorder is defined as a difficulty initiating or maintaining sleep or waking up earlier than expected unable to return to sleep, followed by a feeling of nonrestorative and poor quality sleep, present for at least three months, with consequences on daytime functioning. Studies have shown that insomnia affects cognitive function, especially executive functions. However, researches that sought to investigate the relationship between primary insomnia and executive functioning were quite inconsistent from a methodological point of view, especially in regard to the variability of the used methods, the heterogeneity of diagnostic criteria for insomnia and the control of sleep altering drugs. In this sense, the present study aimed to investigate the relationship between insomnia and executive functions in adults. The participants were 29 people, from both genders, aged 20-55 years old. Participants were divided into three groups, one composed of 10 people with primary insomnia who used sleep medication (GIM), nine people with primary insomnia who did not use medication (GInM) and 10 healthy people who composed the control group (CG). The research was conducted in two stages. The first one involved a diagnostic evaluation for insomnia disorder through a clinical interview and the application of the following protocols: the Athens Insomnia Scale, the Insomnia Severity Index, Sleep Journal (for 14 days), Pittsburgh Sleep Quality Index (PSQI), the Stanford Sleepiness Test, depression and anxiety Beck inventories, and Lipp’s Iventory of stress symptoms for adults. After this stage, the evaluation of executive functions was performed by applying a battery of neuropsychological tests composed by the following tests: Wisconsin, Stoop Test, Colored trails Test, the Tower of London Test, Iowa Gambling Task (IGT) and WAIS III subtest digit span, which measured selective attention, inhibitory control, cognitive flexibility, planning, problem solving, decision making and working memory, respectively. The results showed that insomniacs (GIM and GInM) showed higher sleep latency, shorter sleep duration and lower sleep efficiency compared to the CG. In regard to the performance in executive functions, no statistically significant difference between groups was observed in the evaluated modalities. However, the data show evidence that, compared to GInM and GC, the performance of GIM was lower on tasks that required quick responses and changes in attention focus. On the other hand, GInM, when compared to GIM and GC, showed a better performance on tasks involving cognitive flexibility. Furthermore, impaired sleep measures were correlated with the worst performance of insomniacs in all components evaluated. In conclusion, people with the insomnia disorder showed a performance similar to healthy people’s in components of the executive functioning. Thus, one can infer that there is a relationship between primary insomnia and executive functions in adults.

Efeito agudo do exercício aeróbio vigoroso sobre as funções executivas em adolescentes

Executive functions are determinant cognitive processes for student success, since they execute and control complex cognitive activities such as reasoning, planning and solving problems. The development of the executive functions performances begin early at childhood going through the adolescence until adulthood, concomitant with the neuroanatomical, functional and blood perfusion changes over the brain. In this scenario, exercise has been considered an important environmental factor for neurodevelopment, as well as for the promotion of cognitive and brain health. However, there are no large scientific studies investigating the effects of a single vigorous aerobic exercise session on executive functions in adolescents. Objective: To verify the acute effect of vigorous aerobic exercise on executive functions in adolescents. Methods: A randomized controlled trial (RCT) with crossover design was used. 20 pubescent from both sexes/gender with age between 10 and 16 years were submitted to two sessions of 30min each: 1) The aerobic exercise session intensity was between 65 and 75% of heart rate reserve, in which 5min for warm-up, 20min at the target intensity and 5min of cool down; and 2) control session watching cartoons. The computerized Stroop test – Testinpacs and trail making test were used to evaluate the inhibitory control and cognitive flexibility assessment respectively, before and after both experimental and control sessions. The reaction time (RT) and number of errors (n) of Stroop test were recorded. The total time (TT) and the number of errors (n) of the trail making test were also recorded. Results: The control session’s RT did not present significant differences in the Stroop test. On the other hand, the exercise session’s RT decreased significantly (p<0.01) after the session. The number of errors made at the Stroop test had no significant differences in control and exercise sessions. The ΔTT of trail making test of exercise session was significantly (p<0.001) lower than the control session’s. Errors made in trail making test did not show significant differences between control and exercise sessions. Additionally, there was significant and positive association among the Stroop test ΔRT of exercise session with xiii chronological age (r= 0.635, p=0.001; r 2 = 0.404, p=0.003) and sexual maturation (rs= 0.580, p=0.007; r 2 = 0.408, p=0.002). Differently, there was no association among the control session ΔRT and chronological age (r= – 0.144, p=0.273; r 2 = 0.021, p=0.545) or sexual maturation (rs= –0.155, p=0.513; r 2 = 0.015, p=0.610). Conclusion: Vigorous aerobic exercise seems to improve acutely executive functions in adolescents. The effect of exercise on inhibitory control performance was associated to pubertal stage and chronological age. In other words, the benefits of exercise were more evident in early adolescence (↑ ΔRT) and its magnitude decreases along the growing up process.

Sorting Test, Tower Test, and BRIEF-SR do not predict school performance of healthy adolescents in preuniversity education

Executive functions (EF) such as self-monitoring, planning, and organizing are known to develop through childhood and adolescence. They are of potential importance for learning and school performance. Earlier research into the relation between EF and school performance did not provide clear results possibly because confounding factors such as educational track, boy-girl differences, and parental education were not taken into account. The present study therefore investigated the relation between executive function tests and school performance in a highly controlled sample of 173 healthy adolescents aged 12–18. Only students in the pre-university educational track were used and the performance of boys was compared to that of girls. Results showed that there was no relation between the report marks obtained and the performance on executive function tests, notably the Sorting Test and the Tower Test of the Delis-Kaplan Executive Functions System (D-KEFS). Likewise, no relation was found between the report marks and the scores on the Behavior Rating Inventory of Executive Function—Self-Report Version (BRIEF-SR) after these were controlled for grade, sex, and level of parental education. The findings indicate that executive functioning as measured with widely used instruments such as the BRIEF-SR does not predict school performance of adolescents in preuniversity education any better than a student's grade, sex, and level of parental education.

Propriedades Psicométricas da Bateria de Avaliação Frontal numa Amostra de Adultos da População Portuguesa

The Frontal Assessment Batery / A Bateria de Avaliação Frontal (FAB) é um teste neuropsicológico, constituído por seis subtestes, cujo objetivo é avaliar a disfunção executiva global, nomeadamente as funções relacionadas com o lobo frontal, tais como a concetualização, flexibilidade mental, programação motora, sensibilidade à interferência, controlo inibitório e autonomia ambiental frontal. De forma a contribuir para o avanço dos estudos normativos em Portugal, esta dissertação tem como objetivo avaliar as propriedades psicométricas da FAB, numa amostra de adultos da população portuguesa. O protocolo abrangeu a seguinte bateria de testes neuropsicológicos: Bateria de Avaliação Frontal, Figura Complexa de Rey, Matrizes Progressivas de Raven e Teste do Desenho do Relógio. A amostra deste estudo incluiu 376 indivíduos, 155 do sexo masculino e 221 do sexo feminino. Os resultados desta investigação sugerem que a pontuação da FAB é influenciada por algumas variáveis sociodemográficas, designadamente a idade, escolaridade, profissões e região. A análise correlacional mostrou que há apenas uma correlação positiva moderada entre a FAB e as Matrizes Progressivas de Raven. Apesar da consistência interna da FAB ser baixa, existe uma estabilidade temporal moderada. Ao finalizar, consideramos que a FAB reúne os requisitos para se apresentar como uma bateria útil e eficaz, demonstrando um grau razoável de estabilidade temporal, mas fraca consistência interna, sugerindo que a FAB não é indicada para amostra não clínica. / The Frontal Assessment Baterry (FAB) is a neuropsychological test, composed of six subtests, whose aim is to assess the overall executive dysfunction, namely functions related to the frontal lobe, such as conceptualization, mental flexibility, motor programming, sensitivity to interference, inhibitory control and environmental autonomy. In order to contribute to the advancement of normative studies in Portugal, this dissertation aim to evaluate the psychometric properties of the FAB, in an adult sample of the portuguese population. The protocol included the following battery of neuropsychological tests: Frontal Assessment Battery, Complex Figure of Rey, Raven's Progressive Matrices and Clock Drawing Test. The sample this study included 376 individuals, 155 male and 221 female. The results of this investigation suggest that FAB is influenced by some sociodemographic variables, namely age, education, profession and region. The correlational analysis showed that there is only a moderate positive correlation between the FAB and the Raven Progressive Matrices. However, also they found low positive correlations between the FAB and the Complex Figure of Rey, and Clock Drawing Test. Although the FAB has a low internal consistency, there is a moderate temporal stability. Finally, we consider that the FAB gathers the requirements to present itself as a useful and effective battery, demonstrating a reasonable degree of temporal stability, but weaker internal consistency, suggesting that the FAB is not indicate for non-clinical sample.

Propriedades Psicométricas do Teste Stroop numa Amostra de Adultos da População Portuguesa: estudo preliminar

Objetivos: O presente estudo insere-se no Projeto - Estudos Normativos de Instrumentos Neuropsicologicos (ENIN) e tem por objetivo analisar as propriedades psicométricas do Teste Stroop, fornecendo dados normativos de uma amostra da População Portuguesa. Métodos: Selecionámos e inquirimos 671 sujeitos. As variáveis independentes estudadas foram idade, sexo, escolaridade e profissão. Foram utilizados vários testes neste estudo, contribuindo para a obtenção de validade convergente: Bateria de Avaliação Frontal-FAB, Figura Complexa de Rey-Osterrieth e Teste do Relógio. Foram estudadas a consistência interna e a estabilidade temporal do Teste Stroop. Resultados: A nossa amostra ficou constituída por 310 sujeitos (46,2%) do sexo masculino e 361 (53,8%) do sexo feminino, com idades compreendidas entre os 18 e 100 anos (M = 41,12; DP = 20,85). No que se refere ao nível de escolaridade (M = 5,71; DP = 1,45), este variou entre o 1º Ciclo do Ensino Básico e o Ensino Superior. As profissões, exercidas inseriram-se maioritariamente na categoria das profissões intelectuais (N = 281; 84,9%). Relativamente às variáveis sociodemográficas, verificámos que a idade, sexo, escolaridade e profissão influenciam nas provas de Leitura e Nomeação de Cor do Teste Stroop. No que diz respeito à validade convergente, observámos que a prova de Nomeação de Cor apresentou correlações positivas fracas com o FAB, Figura Complexa de Rey-Cópia (FCR-Cópia) e Teste do Relógio, e correlações positivas moderadas com a prova de Leitura. A consistência interna do Teste Stroop apresentou uma elevada confiabilidade (α = 0,99). A correlação teste-reteste apenas se mostrou significativa para a prova de Nomeação de Cor. Conclusão: Este estudo mostra que o Teste Stroop é promissoriamente confiável como instrumento de avaliação neuropsicológica, podendo potencialmente ser utilizado para qualquer faixa etária da população. Em estudos futuros são necessárias amostras com números mais elevados de participantes nas faixas etárias acima dos 30 anos, representativas dos níveis de escolaridade abaixo do 9ºano, a exercerem profissões manuais, e com residência noutras regiões geográficas para além do Centro. / Objectives: The present study is part of the Project - Estudos Normativos de Instrumentos Neuropsicologicos (ENIN) and aims to analyze the psychometric properties of the Stroop test. Methods: We have selected, and we also enquired 671 subjects. The independent variables studied were age, gender, education and profession. Several tests were used in this study for analysis of convergent validity: convergent validity: Frontal Assessment Battery-FAB, Complex Figure Rey-Osterrieth and the clock test. We also studied the internal consistency and the temporal stability of the Stroop test. Results: Our sample was composed of 310 subjects (46.2%) male and 361 (53.8%) females, with ages between 18 and 100 years (M = 41.12; SD = 20.85). The level of schooling (M = 5.71; SD = 1.45) ranged between the 1st cycle and the Higher Education. The professions were mainly intellectual ones (N = 281; 84.9%). On sociodemographic variables, we found that the age, sex, education and profession influenced reading and Color naming of Stroop test. Regarding convergent validity, Color naming showed weak positive correlations with the FAB, Complex Figure Rey-Copy, and the clock test. Color naming moderate positive correlations with the reading. The internal consistency of the Stroop test was high (α = 0.99). The test-retest correlation was significant only for Color naming. Conclusion: This study shows that the Stroop test is promissory reliable instrument of neuropsychological assessment and may potentially be used for any age range of the population. In future research, it is necessary to enroll samples with higher numbers of participants above 30 years, representative of the levels of schooling below the 9º grade, with more manual professions represented, and with residence in other geographic regions in addition to the Center region of Portugal.

Propriedades psicométricas da versão Torga do Teste Stroop

RESUMO Objetivos: Uma nova versão portuguesa do teste Stroop é fundamental para a avaliação neuropsicológica. A versão portuguesa prévia incluía cores que muitas pessoas não conseguiam distinguir. Assim, é objetivo descrever as propriedades psicométricas de uma nova versão, designada versão Torga do Teste Stroop, numa amostra da população portuguesa. Métodos: Inserida no projeto Estudos Normativos de Instrumentos Neuropsicológicos, esta investigação conta com uma amostra global constituída por 544 participantes (241 homens e 303 mulheres) com idades compreendidas entre os 18 e os 97 anos. A avaliação foi realizada com recurso à versão Torga do Teste Stroop, à Figura Complexa de Rey-Osterrieth e à Bateria de Avaliação Frontal enquanto instrumentos de avaliação das funções executivas. Resultados: A versão Torga do Teste Stroop revelou uma consistência interna muito boa (α de Cronbach = 0,99). Revelou também adequada estabilidade temporal e validade convergente. Conclusão: A versão Torga do Teste Stroop aparenta ser um instrumento apropriado à avaliação neuropsicológica de adultos portugueses. Considerando a importância deste teste no contexto da avaliação neuropsicológica, incentivam-se estudos com novas amostras, incluindo amostras clínicas. ABSTRACT Goals: A new Portuguese version of the Stroop Test is essential for the neuropsychological assessment. The previous Portuguese version included colors that many people could not distinguish. Thus, it is aimed to describe the psychometric properties of a new version, called the Torga version of the Stroop Test in a sample of the Portuguese population. Methods: Being part of the Estudos Normativos de Instrumentos Neuropsicológicos/ Normative Studies of Neuropsychological Instruments, this research has a global sample of 544 subjects (241 men and 303 women) aged from 18 to 97 years. The assessment included the Torga version of the Stroop Test, the Rey-Osterrieth Complex Figure and the Frontal Battey Assessment, used as measures of executive functions. Results: The Torga version of the Stroop Test showed a very good internal consistency (Cronbach's α = 0.99). It also revealed an adequate temporal stability and convergent validity. Conclusion: The Torga version of the Stroop Test appears to be an adequate instrument for the neuropsychological assessment of Portuguese adults. Considering the importance of this test in the context of neuropsychological assessment, more studies with new samples, including clinical samples are encouraged.

Neuroreceptor availability and cerebral morphology in human obesity

Obesity is a major challenge to human health worldwide. Little is known about the brain mechanisms that are associated with overeating and obesity in humans. In this project, multimodal neuroimaging techniques were utilized to study brain neurotransmission and anatomy in obesity. Bariatric surgery was used as an experimental method for assessing whether the possible differences between obese and non-obese individuals change following the weight loss. This could indicate whether obesity-related altered neurotransmission and cerebral atrophy are recoverable or whether they represent stable individual characteristics. Morbidly obese subjects (BMI ≥ 35 kg/m2) and non-obese control subjects (mean BMI 23 kg/m2) were studied with positron emission tomography (PET) and magnetic resonance imaging (MRI). In the PET studies, focus was put on dopaminergic and opioidergic systems, both of which are crucial in the reward processing. Brain dopamine D2 receptor (D2R) availability was measured using [11C]raclopride and µ-opioid receptor (MOR) availability using [11C]carfentanil. In the MRI studies, voxel-based morphometry (VBM) of T1-weighted MRI images was used, coupled with diffusion tensor imaging (DTI). Obese subjects underwent bariatric surgery as their standard clinical treatment during the study. Preoperatively, morbidly obese subjects had significantly lower MOR availability but unaltered D2R availability in several brain regions involved in reward processing, including striatum, insula, and thalamus. Moreover, obesity disrupted the interaction between the MOR and D2R systems in ventral striatum. Bariatric surgery and concomitant weight loss normalized MOR availability in the obese, but did not influence D2R availability in any brain region. Morbidly obese subjects had also significantly lower grey and white matter densities globally in the brain, but more focal changes were located in the areas associated with inhibitory control, reward processing, and appetite. DTI revealed also signs of axonal damage in the obese in corticospinal tracts and occipito-frontal fascicles. Surgery-induced weight loss resulted in global recovery of white matter density as well as more focal recovery of grey matter density among obese subjects. Altogether these results show that the endogenous opioid system is fundamentally linked to obesity. Lowered MOR availability is likely a consequence of obesity and may mediate maintenance of excessive energy uptake. In addition, obesity has adverse effects on brain structure. Bariatric surgery however reverses MOR dysfunction and recovers cerebral atrophy. Understanding the opioidergic contribution to overeating and obesity is critical for developing new psychological or pharmacological treatments for obesity. The actual molecular mechanisms behind the positive change in structure and neurotransmitter function still remain unclear and should be addressed in the future research.

Individual Differences in Reactions to Peer Victimization: The Moderating Role of Temperament and Sex

This study examined whether temperamental traits and sex moderate the effects of peer victimization on children’s adjustment over a year to identify factors that put victimized children at heightened risk for adjustment difficulties. Children (N = 282; M age = 7.94 years, SD = 0.32) and teachers reported on exposure to peer victimization. Parents provided ratings of children’s temperament (i.e., inhibitory control and negative emotionality) and depressive symptoms, and teachers provided ratings of children’s aggression. Results revealed that overt victimization predicted aggression in girls with low levels of inhibitory control. Results also revealed that total victimization predicted depressive symptoms in girls with high levels of negative emotionality and in boys with low levels of negative emotionality. This research identifies temperament and sex as contributors to individual differences in children’s reactions to peer victimization. The findings are discussed in the context of temperament x environment and diathesis-stress frameworks.

Neurobiologia e cognição na aprendizagem simultânea de línguas estrangeiras : aquisição multilingue do léxico

Na sociedade moderna, constata-se que os indivíduos multilingues compreendem e falam várias línguas e que essa proficiência tem despertado, ao longo de várias décadas, a curiosidade de numerosos especialistas no assunto (neurolinguistas, psicolinguistas). Sobre este assunto, Dijkstra (2003:11) preconiza que os falantes multilingues devem ter armazenado um vasto número de palavras no seu léxico mental no qual parece ser difícil recuperar uma palavra. Neste contexto, o presente trabalho, que se enquadra no Mestrado em Português Língua Não Materna, oferece uma revisão da literatura sobre o conhecimento neurolinguístico e psicolinguístico da aquisição multilingue do léxico em sujeitos bi / multilingues ; tendo como ponto nevrálgico o controlo inibitório e o acesso lexical. No decorrer desta pesquisa, a qual pôde contar com a participação de trinta e três informantes falantes de português europeu (3 monolingues, 3 bilingues, 5 trilingues e 22 multilingues), procurou-se averiguar se os informantes bi / multilingues seriam mais rápidos e precisos do que os monolingues, aquando da realização de tarefas trilingues de nomeação oral de imagens e de decisão lexical. A investigação realizada fornece dados para uma reflexão sobre o modo como falantes com estas particularidades acedem ao (s) seu (s) reportório (s) linguístico (s), bem como sobre a forma como exercem o controlo inibitório sobre o seu vasto campo linguístico.

Efeitos da prática do Jiu-Jitsu brasileiro no controle cognitivo de estudantes do Ensino Secundário da Rede Pública de Abu Dhabi, Emirados Árabes Unidos

Uma das formas de atividade física que tem revelado expressivos resultados na mediação comportamental e cognitiva são as Artes Marciais (AM). Dentre elas, o Jiu-Jitsu Brasileiro ou BJJ (Brazilian Jiu-Jitsu) tem se mostrado cada vez mais popular entre jovens de idade escolar, no entatanto nenhum estudo sobre os seus efeitos nas Funções Executivas (FE) foi encontrado. O objetivo desse estudo foi primeiramente, encontrar diferenças nas FE com a pratica do BJJ; secundariamente, pretendeu-se observar o tipo de correlação entre as FE e os niveis de participação; e por fim posicionar os resultados deste estudo a outros trabalhos similares da literatura científica. O estudo avaliou 125 alunos de uma escola pública de Abu Dhabi, antes e após 6 meses de prática, através de um modelo não randomizado. Após todas as exclusões, 59 alunos foram separados em 3 niveis de participação e correlacionados com os resultados do teste de Stroop (VST - Victoria Stroop Test). Os resultados deste estudo mostraram que 30 sessões de BJJ, foram suficientes para oferecer significativas diferenças no Controle Inibitório (CI). Sua boa participação (2 a 3 vezes por semana), não somente mostrou grande tamanho de efeito (SE) comparado a baixa e media participação, como maiores SE comparado a outras formas de Atividade Fisica e Artes Marciais Tradicionais como o Tae Kwon Do e Wu Shu (Kung Fu). Com uma moderada correlação, sua participação apontou uma capacidade de influenciar em 20,8% o (CI) sobre atividades automáticas, bem como 27,3% a distração sobre atividades irrelevantes. Esses achados sugerem que a pratica do BJJ possa levar a melhoras nas Funções Executivas de pré-adolescentes nativos dos Emirados Arabes Unidos.

When do dialects become languages? A cognitive perspective

Several definitions exist that offer to identify the boundaries between languages and dialects, yet these distinctions are inconsistent and are often as political as they are linguistic (Chambers & Trudgill, 1998). A different perspective is offered in this thesis, by investigating how closely related linguistic varieties are represented in the brain and whether they engender similar cognitive effects as is often reported for bilingual speakers of recognised independent languages, based on the principles of Green’s (1998) model of bilingual language control. Study 1 investigated whether bidialectal speakers exhibit similar benefits in non-linguistic inhibitory control as a result of the maintenance and use of two dialects, as has been proposed for bilinguals who regularly employ inhibitory control mechanisms, in order to suppress one language while speaking the other. The results revealed virtually identical performance across all monolingual, bidialectal and bilingual participant groups, thereby not just failing to find a cognitive control advantage in bidialectal speakers over monodialectals/monolinguals, but also in bilinguals; adding to a growing body of evidence which challenges this bilingual advantage in non-linguistic inhibitory control. Study 2 investigated the cognitive representation of dialects using an adaptation of a Language Switching Paradigm to determine if the effort required to switch between dialects is similar to the effort required to switch between languages. The results closely replicated what is typically shown for bilinguals: Bidialectal speakers exhibited a symmetrical switch cost like balanced bilinguals while monodialectal speakers, who were taught to use the dialect words before the experiment, showed the asymmetrical switch cost typically displayed by second language learners. These findings augment Green’s (1998) model by suggesting that words from different dialects are also tagged in the mental lexicon, just like words from different languages, and as a consequence, it takes cognitive effort to switch between these mental settings. Study 3 explored an additional explanation for language switching costs by investigating whether changes in articulatory settings when switching between different linguistic varieties could - at least in part – be responsible for these previously reported switching costs. Using a paradigm which required participants to switch between using different articulatory settings, e.g. glottal stops/aspirated /t/ and whispers/normal phonation, the results also demonstrated the presence of switch costs, suggesting that switching between linguistic varieties has a motor task-switching component which is independent of representations in the mental lexicon. Finally, Study 4 investigated how much exposure is needed to be able to distinguish between different varieties using two novel language categorisation tasks which compared German vs Russian cognates, and Standard Scottish English vs Dundonian Scots cognates. The results showed that even a small amount of exposure (i.e. a couple of days’ worth) is required to enable listeners to distinguish between different languages, dialects or accents based on general phonetic and phonological characteristics, suggesting that the general sound template of a language variety can be represented before exact lexical representations have been formed. Overall, these results show that bidialectal use of typologically closely related linguistic varieties employs similar cognitive mechanisms as bilingual language use. This thesis is the first to explore the cognitive representations and mechanisms that underpin the use of typologically closely related varieties. It offers a few novel insights and serves as the starting point for a research agenda that can yield a more fine-grained understanding of the cognitive mechanisms that may operate when speakers use closely related varieties. In doing so, it urges caution when making assumptions about differences in the mechanisms used by individuals commonly categorised as monolinguals, to avoid potentially confounding any comparisons made with bilinguals.

In vivo co-ordinated interactions between inhibitory systems to control glutamate mediated hippocampal excitability.

We present an overview of the long-term adaptation of hippocampal neurotransmission to cholinergic and GABAergic deafferentation caused by excitotoxic lesion of the medial septum. Two months after septal microinjection of 2.7 nmol a -amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA), a 220% increase of GABA A receptor labelling in the hippo- campal CA3 and the hilus was shown, and also changes in hippocampal neurotransmission characterised by in vivo microdialysis and HPLC. Basal amino acid and purine extra- cellular levels were studied in control and lesioned rats. In vivo effects of 100 m M KCl perfusion and adenosine A 1 receptor blockade with 1,3-dipropyl- 8-cyclopentylxanthine (DPCPX) on their release were also investigated. In lesioned animals GABA, glutamate and glutamine basal levels were decreased and taurine, adenosine and uric acid levels increased. A similar response to KCl infusion occurred in both groups except for GABA and glutamate, which release decreased in lesioned rats. Only in lesioned rats, DPCPX increased GABA basal level and KCl-induced glutamate release, and decreased glutamate turnover. Our results evidence that an excitotoxic septal lesion leads to increased hippocampal GABA A receptors and decreased glutamate neurotransmis- sion. In this situation, a co-ordinated response of hippocampal retaliatory systems takes place to control neuron excitability.

Inhibitory mechanism of the nucleus of the solitary tract involved in the control of cardiovascular, dipsogenic, hormonal, and renal responses to hyperosmolality

The nucleus of the solitary tract (NTS) is the primary site of visceral afferents to the central nervous system. In the present study, we investigated the effects of lesions in the commissural portion of the NTS (commNTS) on the activity of vasopressinergic neurons in the hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei, plasma vasopressin, arterial pressure, water intake, and sodium excretion in rats with plasma hyperosmolality produced by intragastric 2 M NaCl (2 ml/rat). Male Holtzman rats with 15-20 days of sham or electrolytic lesion (1 mA; 10 s) of the commNTS were used. CommNTS lesions enhanced a 2 M NaCl intragastrically induced increase in the number of vasopressinergic neurons expressing c-Fos in the PVN (28 ± 1, vs. sham: 22 ± 2 c-Fos/AVP cells) and SON (26 ± 4, vs. sham: 11 ± 1 c-Fos/AVP cells), plasma vasopressin levels (21 ± 8, vs. sham: 6.6 ± 1.3 pg/ml), pressor responses (25 ± 7 mmHg, vs. sham: 7 ± 2 mmHg), water intake (17.5 ± 0.8, vs. sham: 11.2 ± 1.8 ml/2 h), and natriuresis (4.9 ± 0.8, vs. sham: 1.4 ± 0.3 meq/1 h). The pretreatment with vasopressin antagonist abolished the pressor response to intragastric 2 M NaCl in commNTS-lesioned rats (8 ± 2.4 mmHg at 10 min), suggesting that this response is dependent on vasopressin secretion. The results suggest that inhibitory mechanisms dependent on commNTS act to limit or counterbalance behavioral, hormonal, cardiovascular, and renal responses to an acute increase in plasma osmolality. © 2013 the American Physiological Society.