When making decisions, individuals evaluate several possible outcomes of their choice; however, some display heightened reward sensitivity, despite the potential for future negative consequences, which can lead one to make risky choices. Rewards are processed in the mesolimbic dopamine reward system, and this system is in part modulated by genetic polymorphisms that are associated with dopamine transmission. The current study tested if genetic polymorphisms that are associated with enhanced dopamine neurotransmission will be more neurally reward sensitive, score higher on self-reported impulsivity, and make riskier choices. In a sample of 85 participants, five genetic polymorphisms were genotyped and used to create a genetic risk score that represented dopamine transmission efficiency. Two groups (high and low efficiency) were created via median split and then compared on neural reward sensitivity (assessed by event-related potentials, specifically, the medial-frontal negativity [MFN] and the error-related negativity), impulsivity (assessed via self-report), and risky choice (measured using the Balloon Analogue Risk Task and self-report measures). Results indicated that individuals with higher levels of dopamine displayed a less negative MFN and more drinking behaviors than those with lower levels of dopamine. These results suggest that individuals with higher levels of dopamine are less sensitive to punishments, which could lead them to make riskier choices.

Mice display robust and stereotyped behaviors towards pups: virgin males typically attack pups, while virgin females and sexually experienced males display parental care. I show here that virgin males that are genetically impaired in vomeronasal sensing do not attack pups and are parental, suggesting a key role of the vomeronasal system in controlling male infanticide. In addition, we have identified putative vomeronasal receptors (or receptor groups) for the detection of pup odors, thus uncovering new tools for the molecular and genetic dissection of male infanticide. Further, we have uncovered galanin-expressing neurons in the medial preoptic area (MPOA) as key regulators of male and female parental behavior. Genetic ablation of MPOA galanin- neurons results in dramatic impairment of parental responses in both virgin females and sexually experienced males. In addition, optogenetic activation of these cells in virgin males suppresses infanticide and induces pup grooming. Thus, MPOA galanin-expressing neurons emerge as an essential node of regulation of innate behavior in the hypothalamus that orchestrates male and female parenting while opposing vomeronasal circuits underlying infanticide. Our results provide an entry point for the genetic and circuit-level dissection of mouse parental behavior and its modulation by social experience.

The principal neurons of the medial superior olive (MSO) are considered to be responsible for transforming the temporal information present in the binaural acoustic stimulus into an output encoding sound location along the horizontal axis. Spatial resolution of sound localization depends critically on the time resolution with which MSO neurons can detect microsecond differences in the timing of inputs from the two ears. This fast temporal processing is contingent on voltage gated ion channels. The work presented in this thesis demonstrates that two currents, namely a hyperpolarization activated cationic current and low voltage activated potassium current dynamically interact to regulate the intrinsic time resolution of MSO neurons. We observe that the ability of MSO neurons to perform sub-millisecond temporal processing matures after birth, especially around the time of the clearing of the auditory canal. Hyperpolarization activated cationic current was found to be one of the underlying mechanisms transforming slow immature MSO neurons into temporally precise adult MSO neurons. / text

Impulse control, an executive process that restrains inappropriate actions, is impaired in numerous psychiatric conditions. This thesis reports three experiments that utilized a novel animal model of impulse control, the response inhibition (RI) task, to examine the substrates that underlie learning this task. In the first experiment, rats were trained to withhold responding on the RI task, and then euthanized for electrophysiological testing. Training in the RI task increased the AMPA/NMDA ratio at the synapses of pyramidal neurons in the prelimbic, but not infralimbic, region of the medial prefrontal cortex. This enhancement paralleled performance as subjects underwent acquisition and extinction of the inhibitory response. AMPA/NMDA was elevated only in neurons that project to the ventral striatum. Thus, this experiment identified a synaptic correlate of impulse control. In the second experiment, a separate group of rats were trained in the RI task prior to electrophysiological testing. Training in the RI task produced a decrease in membrane excitability in prelimbic, but not infralimbic, neurons as measured by maximal spiking evoked in response to increasing current injection. Importantly, this decrease was strongly correlated with successful inhibition in the task. Fortuitously, subjects trained in an operant control condition showed elevated infralimbic, but not prelimbic, excitability, which was produced by learning an anticipatory signal that predicted imminent reward availability. These experiments revealed two cellular correlates of performance, corresponding to learning two different associations under distinct task conditions. In the final experiment, rats were trained on the RI task under three conditions: Short (4-s), long (60-s), or unpredictable (1-s to 60-s) premature phases. These conditions produced distinct errors on the RI task. Interestingly, amphetamine increased premature responding in the short and long conditions, but decreased premature responding in the unpredictable condition. This dissociation may arise from interactions between amphetamine and underlying cognitive processes, such as attention, timing, and conditioned avoidance. In summary, this thesis showed that learning to inhibit a response produces distinct synaptic, cellular, and pharmacological changes. It is hoped that these advances will provide a starting point for future therapeutic interventions of disorders of impulse control. / Thesis (Ph.D, Neuroscience Studies) -- Queen's University, 2011-07-11 09:44:54.815

With the general increase in Rugby union's popularity the past decade, there has been an increase in sport injuries, both from acute and overuse trauma. Approximately half of all sport injuries may be attributed to overuse or repetitive micro trauma rather than a single traumatic event. Although very few overuse injuries have an established aetiology, the fact that over 80% of these injuries occurs at or below the knee suggests that there may be some common mechanisms in the aetiology. It could only be stated with certainty that the aetiology of these injuries is multifactorial and diverse, with both extrinsic and intrinsic factors contributing. Many intrinsic factors (personal) predispose athletes to develop overuse injuries. Intervention of intrinsic injury risk factors is more problematic, as intrinsic risk factors are often difficult to examine and even more difficult to rehabilitate than external factors. Extrinsic risk factors (environmental) that are independent of the injured person can be influenced through the intervention of the extrinsic factors. Main attention should be paid not to the treatment of the site of injury but to the possible cause of the symptoms. It is therefore vital that coaches and medical teams have a complete understanding of the incidence, nature, severity, and causes of injuries in order to review the adequacy of their injury prevention, treatment and rehabilitation. The objectives of this study were to determine the effect of selected anthropometric parameters, biomechanical malalignment and flexibility on the prevalence of Medial tibial stress syndrome (MTSS) in U/19 university rugby players of the 2006 season of the North-West University (NWU) Rugby Institute (RI). A prospective once-off subject availability study was performed that included U/19 rugby union players of the RI of the NWU (n=91). Selected biomechanical and anthropometrical assessments were made. Biomechanical and anthropometrical assessments were preformed on all subjects before the start of the season. All existing injuries were recorded by means of an injury history questionnaire. Descriptive statistics (e.g. mean and standard deviations) and contingency tables were used to analyse the data. Effect sizes were used to decide on the practical significance of the findings. A cut-off point of 0.8 (large effect) was set for practical significance of differences between means. Players with MTSS had a wider Bi-iliocristal width than those without MTSS. There were leg length differences for both players with and without MTSS for Hiospinale, Trochanterion-Tibiale lateral and Tibial lateral length. Iliospinale- and Trochanterion-Tibiale lateral length differences presented with the largest length difference. Iliospinale, Trochanterion-Tibiale lateral and Tibial lateral length difference had a small effect. Only Bi-iliocristal width presented with a medium effect. Hamstrings, Gastrocnemius and Plantaris as well as Soleus and Popliteus flexibility of players without MTSS were tighter than those of players who suffered from MTSS. Only Hamstring tightness had a small effect. Gastrocnemius and Plantaris as well as Soleus and Popliteus presented with a medium effect. Players without MTSS had a more flexible TFL on their right side. All the other flexibility measurements of the Thomas test presented that players without MTSS had a more inflexible profile. Effect size was not analysed because of the small sample sizes in some of the cells. Players without MTSS presented with an overall more inflexible profile than those with MTSS. More players without MTSS supinated at heel contact on both their feet, compared to the players with MTSS. Players without MTSS supinated more on both their feet during mid stance. A small percentage of players with and without MTSS supinated during the propulsion phase. More players without MTSS had a neutral right foot mid stance compared to players with MTSS who had a more neutral mid stance on their right foot. Players with MTSS pronated more with both their feet during propulsion. Players with MTSS pronated mostly during the propulsion phase and mostly had flatter and higher arched feet than players without MTSS. More players with MTSS had a light flat foot, flat foot as well as a high arched foot than players without MTSS. Most of the players with MTSS had normal right arched foot type. None of the players with MTSS had either a light high right foot or a high arched left foot. / Thesis (M.A. (Human Movement Science))--North-West University, Potchefstroom Campus, 2009.

With the general increase in Rugby union's popularity the past decade, there has been an increase in sport injuries, both from acute and overuse trauma. Approximately half of all sport injuries may be attributed to overuse or repetitive micro trauma rather than a single traumatic event. Although very few overuse injuries have an established aetiology, the fact that over 80% of these injuries occurs at or below the knee suggests that there may be some common mechanisms in the aetiology. It could only be stated with certainty that the aetiology of these injuries is multifactorial and diverse, with both extrinsic and intrinsic factors contributing. Many intrinsic factors (personal) predispose athletes to develop overuse injuries. Intervention of intrinsic injury risk factors is more problematic, as intrinsic risk factors are often difficult to examine and even more difficult to rehabilitate than external factors. Extrinsic risk factors (environmental) that are independent of the injured person can be influenced through the intervention of the extrinsic factors. Main attention should be paid not to the treatment of the site of injury but to the possible cause of the symptoms. It is therefore vital that coaches and medical teams have a complete understanding of the incidence, nature, severity, and causes of injuries in order to review the adequacy of their injury prevention, treatment and rehabilitation. The objectives of this study were to determine the effect of selected anthropometric parameters, biomechanical malalignment and flexibility on the prevalence of Medial tibial stress syndrome (MTSS) in U/19 university rugby players of the 2006 season of the North-West University (NWU) Rugby Institute (RI). A prospective once-off subject availability study was performed that included U/19 rugby union players of the RI of the NWU (n=91). Selected biomechanical and anthropometrical assessments were made. Biomechanical and anthropometrical assessments were preformed on all subjects before the start of the season. All existing injuries were recorded by means of an injury history questionnaire. Descriptive statistics (e.g. mean and standard deviations) and contingency tables were used to analyse the data. Effect sizes were used to decide on the practical significance of the findings. A cut-off point of 0.8 (large effect) was set for practical significance of differences between means. Players with MTSS had a wider Bi-iliocristal width than those without MTSS. There were leg length differences for both players with and without MTSS for Hiospinale, Trochanterion-Tibiale lateral and Tibial lateral length. Iliospinale- and Trochanterion-Tibiale lateral length differences presented with the largest length difference. Iliospinale, Trochanterion-Tibiale lateral and Tibial lateral length difference had a small effect. Only Bi-iliocristal width presented with a medium effect. Hamstrings, Gastrocnemius and Plantaris as well as Soleus and Popliteus flexibility of players without MTSS were tighter than those of players who suffered from MTSS. Only Hamstring tightness had a small effect. Gastrocnemius and Plantaris as well as Soleus and Popliteus presented with a medium effect. Players without MTSS had a more flexible TFL on their right side. All the other flexibility measurements of the Thomas test presented that players without MTSS had a more inflexible profile. Effect size was not analysed because of the small sample sizes in some of the cells. Players without MTSS presented with an overall more inflexible profile than those with MTSS. More players without MTSS supinated at heel contact on both their feet, compared to the players with MTSS. Players without MTSS supinated more on both their feet during mid stance. A small percentage of players with and without MTSS supinated during the propulsion phase. More players without MTSS had a neutral right foot mid stance compared to players with MTSS who had a more neutral mid stance on their right foot. Players with MTSS pronated more with both their feet during propulsion. Players with MTSS pronated mostly during the propulsion phase and mostly had flatter and higher arched feet than players without MTSS. More players with MTSS had a light flat foot, flat foot as well as a high arched foot than players without MTSS. Most of the players with MTSS had normal right arched foot type. None of the players with MTSS had either a light high right foot or a high arched left foot. / Thesis (M.A. (Human Movement Science))--North-West University, Potchefstroom Campus, 2009.

ABSTRACT Evidence from knockout studies in male mice and from experiments in male rats,in which expression of the estrogen receptor alpha (ERα) gene was inhibited in the medial preoptic area (MPO), suggests that ERα is important in the control of male rat mating behavior. Therefore, in this experiment, we tested the hypothesis that activation of ERα in the MPO is sufficient to maintain mating behavior in castrated male rats receiving subcutaneously (s.c.) dihydrotestosterone (DHT), a non-aromatizable androgen. Accordingly, castrated rats treated with DHT s.c. received MPO implants of either: (i) propyl-pyrazole-triol (PPT) (Stauffer, et al 2000; Katzenellenbogen, et al 2000), a selective ERα agonist, (ii) E2 (positive controls) or (iii) cholesterol (negative controls)and sexual behavior was monitored. PPT was as effective as E2 at maintaining mating behavior suggesting that, in the MPO, ERα is sufficient to mediate responses to E2 that underlie male rat mating behavior.

In diesem Aufsatz werden die Stilisierungen  des Türkendeutsch aus zwei Perspektiven untersucht. Es wird der Frage nachgegangen, wie Türkendeutsch als Ethnolekt von den Medien inszeniert wird und wie sich die Sprecher des Türkendeutsch selbst in den Medien darstellen. Mittels einer Textanalyse sind Hip-Hop-Texte und Texte der Satire variationslinguistisch untersucht worden, wobei die Rap-Texte mit einer Bildanalyse komplettiert wurden. Schließlich wird ein Vergeich der beiden Genres bezüglich primären Ethnolekt und medial-Sekundären Ethnolekt angestellt.

The aim of this thesis is to examine the underlying cognitive and neural processes at play during retrieval of temporal and contextual source information. This was assessed across three experimental chapters. In the first experimental chapter, Chapter 2, the neural loci of context associations were assessed. Rats trained on an odour-context association task were given lesions to either the Lateral Entorhinal Cortex (LEC) or sham lesions. After surgery, performance on the odour-context task was assessed. It was hypothesised that memory for previously learned odour-context associations would be impaired following LEC lesions but not sham lesions. The results supported this hypothesis, demonstrating impaired memory for the previously learned odour-context associations in the LEC lesion group compared to the Sham lesion. In Chapter 3, the underlying retrieval processes used to retrieve time and context in human memory was assessed across three experiments. It was hypothesised that time would be remembered accurately using both recollection and familiarity, while correct context memory should rely on recollection alone. Two out of the three experiments supported this hypothesis, demonstrating that temporal information can be retrieved using familiarity in certain instances. The final experimental Chapter 4 used fMRI to extend Chapter 3 and examine whether neural activity would be greater in regions associated with recollection during memory for context, while activity in familiarity-related regions would be higher during memory for time. Results revealed no support for these predictions with no regions linked to recollection showing greater context-related activity, and no regions previously linked to familiarity exhibiting increased activation as temporal information was retrieved. The results are discussed in relation to established recollection and familiarity frameworks and previous work examining the neural substrates supporting memory for time and context.

Submitted by Ana Maria Fiscina Sampaio (fiscina@bahia.fiocruz.br) on 2012-10-23T17:18:48Z No. of bitstreams: 1 Daniela Almeida Participaçao dos receptores....pdf: 1297031 bytes, checksum: 754812103a71d951c868e902bd43f90c (MD5) / Made available in DSpace on 2012-10-23T17:18:48Z (GMT). No. of bitstreams: 1 Daniela Almeida Participaçao dos receptores....pdf: 1297031 bytes, checksum: 754812103a71d951c868e902bd43f90c (MD5) Previous issue date: 2012 / Fundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, Bahia, Brasil / Situações de estresse repetido ou prolongado podem resultar em vários estados patológicos, como hipertensão arterial, arritmias cardíacas, infarto do miocárdio e até mesmo morte súbita. Embora se tenha muita informação sobre o controle cerebral da pressão arterial, as respostas cardiovasculares ao estresse não são totalmente compreendidas. Dados da literatura mostram a importância do núcleo medial da amigdala (MeA) e da neurotrasmissão histaminérgica no controle autonômico das funções cardiovasculares, no entanto, não há estudos evidanciando o papel das vias histaminérgicas no MeA nas adaptações cardiovasculares evocada pelo estresse emocional. Desta forma, o objetivo desta pesquisa foi estudar a participação dos receptores H1 e H2 no MeA sobre as respostas cardiovasculares em ratos estressados e não-estressados. Ratos Wistar (280-320g) foram submetidos à cirurgia estereotáxica para canulação bilateral do MeA. Passado cinco dias da estereotaxia, os animais foram submetidos a cateterização da artéria carótida esquerda. Vinte e quatro horas após a inserção do cateter, foram iniciados os experimentos com a gravação do registro da pressão arterial pulsátil (PAP) dos animais em condições basais e em livre movimento em suas respectivas caixas de forma continuada. As drogas utilizadas para a microinjeção central foram a mepiramina (antagonista dos receptores H1) nos grupos experimentais I e III e a cimetidina (antagonista dos receptores H2) nos grupos experimentais II e IV. Nos grupos experimentais I e II, 15 min após microinjeção central bilateral de mepiramina ou cimetidina respectivamente, em diferentes doses, os animais foram submetidos a estresse de restrição de movimentos em tubos de polietileno, e a PAP foi registrada continuamente durante 45 min. Após o período de estresse, os animais foram realocados em suas caixas e a PAP foi registrada por mais 30 min. Nos grupos experimentais III e IV, após as microinjeções centrais bilaterais no MeA, a PAP continuou sendo registrada por 75 min em animais sob condições basais e em livre movimento (não estressados). Os animais controles de todos os grupos experimentais receberam microinjeções de salina 0,9%. Os experimentos foram realizados entre 7h00min às 13h00min e os animais não tiveram acesso à água ou ração durante o experimento. Os dados estão expressos como média±E.P.M das variações da PAM e FC. Microinjeções de mepiramina nas doses de 50, 100 e 200 nmol promoveu bloqueio dose-dependente da resposta hipertensiva evocada pelo estresse de restrição. A cimetidina (100 e 200 nmol) atenuou a resposta hipertensiva ao estresse apenas na maior dose utilizada. A resposta anti-hipertensiva ao estresse foi maior nos animais que receberam microinjeções de mepiramina do que de cimetidina nas mesmas doses. Nenhuma das drogas alterou a resposta taquicárdica típica do estresse. Mepiramina ou cimetidina foram incapazes de alterar a PAM ou a FC de animais não estressados. Os dados sugerem que as vias histaminérgicas presentes no MeA medeiam a resposta pressora sem alterar a taquicardia evocadas pelo estresse de restrição, ativando preferencialmente os receptores do tipo H1. Além disto, os dados confirmam a hipótese de que a via histaminérgica no MeA não exerce modulação tônica do sistema cardiovascular. A obtenção de dados adicionais relativos ao papel fisiológico dos receptores histaminérgicos centrais no controle das funções cardiovasculares se reveste de grande importância para as ciências biológicas e para a clínica médica, principalmente quando vinculada à variável estresse. Os resultados deste trabalho contribuem para o esclarecimento da participação destes receptores no controle das funções cardiovasculares. / Repeated long lasting experiences of stress situations may result in various pathologic states such as arterial hypertension, cardiac dysrhythmias, myocardial stroke and even sudden death. Although there is a lot information about the neural control of the arterial blood pressure, especially by the brain stem and some other prosencephalic areas, stress-evoked cardiovascular responses are not totally understood. Previews studies shows the importance of the medial amygdala nucleus (MeA) and of the histaminergic neurotransmission on the autonomic control of cardiovascular functions, however there aren’t studies that evidence the role of the histaminergic pathways in MeA on emotional stress-evoked cardiovascular adaptations. Therefore, the aim of this study was investigate the participation of the histaminergic receptors H1 and H2 in MeA on the cardiovascular responses in stressed and non-stressed rats. Wistar rats (280-320g) were submitted to stereotaxic surgery for bilateral cannulation of MeA. Five days after surgery, animals were submitted to catheterization of the left carotid artery. Twenty four hours after catheter insertion, experiments were started and the pulsatile arterial pressure (PAP) of freely moving rats on basal conditions was recorded. Drugs used for central administration were mepyramine (H1 receptors antagonist) on experimental groups I and III and cimetidine (H2 receptors antagonist) on experimental groups II and IV. At experimental groups I and II, 15 min after central microinjections of mepyramine or cimetidine respectively, in different doses, the rats was submitted to restraint stress in a polyvinyl apparatus, and PAP were continuously recorded for 45 min. After stress period, rats were replaced in their own cages and an additional 30 min were recorded for PAP reestablishment. At experimental groups III and IV, after 30 min of basal recording, rats received bilateral central microinjections of mepyramine or cimetidine in a dose of 200 nmol, respectively, and an additional period of 75 min was recorded in freely moving rats on basal conditions. Saline 0,9% was administered as vehicle in control animals of all experimental groups. Mean arterial pressure (MAP) and heart rate (HR) were, then, calculated from the PAP signal. Experiments occurred between 7:00 and 13:00 and rat did not have access to water and food during the sessions. Data were expressed as mean±S.E.M. of MAP and HR variation. Mepyramine microinjections at doses of 50, 100 and 200 nmol promoted dose-dependent blockade of the restraint stress-evoked hypertensive response. Cimetidine (100 and 200 nmol) attenuated the hypertensive response to stress only at the highest dose administered. The anti-hypertensive response was bigger on animals which received mepyramine than cimetidine. Neither drugs altered the typical stress-evoked tachycardiac responses. Indeed, mepyramine or cimetidina were unable to modify the MAP or HR of freely moving rats on basal conditionals (non-stressed rats). These data suggest that histaminergic pathways in MeA mediates pressor responses without modifying the tachycardia promoted by restraint stress, activating preferentially H1 receptors. Besides, data corroborate to the hypothesis that histaminergic pathways in MeA do not plays tonic modulation of the cardiovascular system. Additional information acquired about physiologic role of central histaminergic receptor on the cardiovascular functions is important to biological science and to medical practice, especially when linked to the stress factor. These data contribute to clarify the role of these receptors on cardiovascular functions