For well over 200 years, scientists and doctors have been poking and prodding brains in every which way in an effort to understand how they work. The earliest pokes were quite crude, often involving permanent forms of brain damage. Though neural injury continues to be an active area of research within neuroscience, technology has given neuroscientists a number of tools for stimulating and observing the brain in very subtle ways. Nonetheless, the basic experimental paradigm remains the same; poke the brain and see what happens. For example, neuroscientists studying the visual or auditory system can easily generate any image or sound they can imagine to see how an organism or neuron will respond. Since neuroscientists can now easily design more pokes then they could every deliver, a fundamental question is ``What pokes should they actually use?' The complexity of the brain means that only a small number of the pokes scientists can deliver will produce any information about the brain. One of the fundamental challenges of experimental neuroscience is finding the right stimulus parameters to produce an informative response in the system being studied. This thesis addresses this problem by developing algorithms to sequentially optimize neurophysiology experiments. Every experiment we conduct contains information about how the brain works. Before conducting the next experiment we should use what we have already learned to decide which experiment we should perform next. In particular, we should design an experiment which will reveal the most information about the brain. At a high level, neuroscientists already perform this type of sequential, optimal experimental design; for example crude experiments which knockout entire regions of the brain have given rise to modern experimental techniques which probe the responses of individual neurons using finely tuned stimuli. The goal of this thesis is to develop automated and rigorous methods for optimizing neurophysiology experiments efficiently and at a much finer time scale. In particular, we present methods for near instantaneous optimization of the stimulus being used to drive a neuron.

No description available.

Biological responses to orthodontic forces involve various cell types, these include fibroblasts, endothelial cells, blood vessels and sensory nerves in the periodontal ligament as well as osteoblasts, osteoclasts and cementoblasts in roots and bone surfaces. Neurotrophins are believed to interact with these cells to initiate the process of bone resorption particularly during orthodontic tooth movement. Neuropeptides released from sensory neurons have been shown to modulate the tissue inflammatory responses. In addition, neurotrophins, including nerve growth factor (NGF), play an important role in neural cell differentiation and survival. The exact localization and function of neurotrophins and neurotrophic receptors in the dento-alveolar complex remains unclear. Moreover, the identity and distribution of structures expressing neurotrophins and neurotrophic receptors has yet to be fully determined. It is reasonable to propose that periodontal ligament and alveolar bone remodelling may be influenced by NGF. In addition, anti-NGF may block neurochemical changes and, hence, inhibit orthodontic tooth movement. The aims of this research were to investigate the cells responsible for NGF secretion within the periodontal ligament (PDL), pulp and bone, and the effect that anti-NGF might have on orthodontic tooth movement. 28, 8 week-old, male Sprague-Dawley rats were randomly divided into control and experimental groups. Fourteen experimental animals had anti-NGF injected paradentally. Animals were sacrificed at 7 and 14 days. Sections from an earlier study were examined and stained using TRAP for osteoclast identification and analysed histomorphometrically to enable comparisons between control and experimental groups. The findings of this investigation indicated that injections of anti-NGF did not significantly affect the rate of tooth movement with the use of different tooth movement measurement methods. TRAP staining proved to be a useful and reliable marker of osteoclasts. TRAP-positive osteoclastic cells were detected in both anti-NGF and control groups. However, the TRAP-positive cells were not stained intensely with NGF immunolabelling. On the other hand, cells that were stained intensely with NGF, were TRAP-negative. The results suggested that both sympathetic and nociceptive nerves might function in counter balance to modulate bone resorption, and osteoclasts might not be directly responsible for NGF secretion within the PDL and bone. Further studies to determine the effect of NGF on tooth movement are warranted to more clearly identify the NGF expressing cells within the rat dento-alveolar complex and possible role played by NGF in orthodontic tooth movement. / http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1297498 / Thesis (D.Clin.Dent.)-- School of Dentistry, 2007

Diss. (sammanfattning) Umeå : Umeå universitet, 2005. / Härtill 6 uppsatser.

Thesis (M.A.)--University of Alabama at Birmingham, 2007. / Description based on contents viewed Oct. 5, 2007; title from title screen. Includes bibliographical references (p. 31-34).

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Esta dissertação visa abordar e dar início a um diálogo sobre a tomada de decisão social juntando aspectos de Administração de Empresas, Psicologia e Neurofisiologia. Primeiramente uma abordagem da evolução do pensamento sobre tomada de decisão é repassada com os conceitos de Simon (1955, 1959, 1979) na sua discussão sobre racionalidade completa e limitada. Isso se dá quando se nota que o ser humano possui limitações na sua racionalidade. Também, nota-se que o nível de incerteza e a complexidade inerente dos problemas aumentou. Soma-se a isso o fato de que, segundo Franks (2010) cada vez mais os seres humanos dependem da interação social para viver. Esse fato torna importante a consideração de aspectos emocionais, de memória e de comportamento. Aspectos de importância da Psicologia que são tratados junto com outros como emoção, cognição e percepção com os trabalhos de Elster (1998), Pretz, Naples e Sternberg (2003). Aspectos de consciência, vieses e heurísticas trazidos por Damásio (1996, 2011), Bazerman e Moore (2010) e Kahneman (2011) auxiliam na compreensão do fenômeno psicológico nessas interações e como eles impactam o processo decisório. Contudo, como melhor compreender a cognição? De onde surgem os comportamentos? Os conceitos de Neurofisiologia podem auxiliar. De forma a iniciar a integração de aspectos da Neurofisiologia na tomada de decisão utilizou-se Bear, Connors e Paradiso (2008), Ohme et al. (2009), entre outros. Foi criado um modelo, baseado na revisão da literatura realizada, visando determinar onde a decisão social poderia ocorrer e como ela poderia se dar em um ambiente organizacional. Dois grupos em uma empresa de pequeno porte foram observados. Ambos os grupos tinham quatro integrantes. No Grupo A três reuniões foram acompanhadas, no Grupo B duas reuniões foram acompanhadas. Utilizaram-se câmeras filmadoras para gravar os encontros de modo que isso permitisse a posterior análise das interações e linguagens verbal e não verbal do grupo. De modo a identificar os aspectos psicológicos dos grupos cinco testes foram aplicados: Wisconsin Card Sorting Game, Iowa Gambling Task, G- 36, Atenção Concentrada e Mini-Plus. Por fim, a revisão de literatura sobre aspectos Neurofisiológicos deu luz a possíveis ligações entre os resultados e esses conceitos. Os principais resultados demonstram que foi possível identificar uma ligação entre as três ciências no que toca a tomada de decisão nas organizações analisadas, tendo-se verificado que essas decisões ocorrem em dois passos principais: o individual e o social. / This master´s thesis aims to approach and start a dialogue about social decision making linking aspects coming from Business Administration, Psychology and Neurophysiology. First an approach regarding the evolution on the thought about decision making is given with the help of concepts from Simon (1959, 1955 e 1979) with his discussion about complete and limited rationality. This discussion start when the human being acknowledges the limitations of his own rationality. Also it is easy to notice the expanding levels of the inherent complexity and uncertainty within the decision making process. Adding to that the fact that, according to Franks (2010), humans have never been more dependent on social interaction in order to live. This facts bring out the importance in considering aspects such as emotions, memory and behavior. This is where Psychology plays its cards and such concepts as emotion, cognition and perception with the help of the works of Elster (1998), Pretz, Naples e Sternberg (2003) are presented. Together in the quest of explaining the psychological phenomenon and how it affects the decision making process aspects of conscience, biases and heuristics brought by Damásio (1996 e 2011), Bazerman e Moore (2010) e Kahneman (2011) are considered. However, how to better comprehend cognition? Where do behaviors come from? Neurophysiology can play an important role in to help answer these questions. As a way to start this link between these concepts and the decision making literature, Bear, Connors e Paradiso (2008), Ohme et al. (2009), among others, were used. A model was developed, based on the revised literature trying to identify where and how the decision making process is present in a social environment. Two groups from a small company were studied. Both groups had four participants. Group A had three meetings accompanied and Group B had two meetings accompanied. Video cameras were uses to tape the meetings in order to allow the analyses of the group´s interactions and verbal and non-verbal language. To help identify the group´s psychological traits, five tests were applied individually: Wisconsin Card Sorting Game, Iowa Gambling Task, G-36, Concentrated Attention and Mini-Plus. Finally a revision of the literature on Neurophysiology sheds light on possible connections between the results and such concepts. The main results show that it is possible to link the three sciences regarding the decision making process in the organizations analyzed, it is concluded that the decision occur in two main steps: individual and social.

Establishing how cognitive abnormalities result in the signs and symptoms that define schizophrenia and anxiety disorders (and their co-morbidity) has become a prominent question in clinically, and sub-clinically, applied research. Abnormal performance in schizophrenia, schizotypy and anxiety has been observed in comparison to healthy individuals on a range of cognitive and behavioural tasks. For example, abnormal attention to irrelevant information has long been recognised by clinicians, which has since encouraged researchers to elucidate the nature of the relationship between schizophrenia, and anxiety more recently, with allocation of attention to stimuli in laboratory studies providing empirical evidence for an attentional view of these disorders. The pre-exposure effect (slower learning to a stimulus that has been rendered familiar by preexposure, relative to a novel cue), hereafter refered to as latent inhibition, has been shown to be inversely correlated with schizotypy, and abnormal in people with schizophrenia, but findings are inconsistent. One potential contributing factor to this inconsistency is that many tasks that purport to measure latent inhibition are confounded by alternative effects that also retard learning and co-vary with schizotypy, such as learned irrelevance (experience of a cue as irrelevant to the occurrence of an outcome due to inconsistent/uncorrelated presentations of a cue and a target). The general aim of this thesis is to address, or begin to address, some of the key questions and limitations with existing research that evaluate latent inhibition and learned irrelevance as potentially useful cognitive endophenotypes for schizophrenia and anxiety disorders. The current experiments separate out the effects of latent inhibition and learned irrelevance to assess the independent effects of these phenomena on schizotypy (and by extension schizophrenia) and anxiety. By teasing apart, the effects of latent inhibition and learned irrelevance the attempt is to disentangle, and improve understanding of attentional abnormalities observed in these sub-clinical traits and by extension, their related pathologies. Across Experiments 1-4, the purpose was two-fold. The first was to address the limitations of existing latent inhibition tasks by designing a paradigm that examines a purer effect of latent inhibition, by minimising the contribution of learned irrelevance, and assessing how this latent inhibition task co-varies with schizotypy and anxiety (Chapter 2: Experiments 1 and 2). The second was to examine the alternative, potentially less equivocal, learned attentional paradigm (learned irrelevance) and assess the relationship between this task with both schizotypy and anxiety (Chapter 3: Experiments 3 and 4). Based on the assumption that latent inhibition and learned irrelevance share similar psychological underpinnings (in this case, attentional), we anticipated the effect of schizotypy and anxiety to be comparable in the two types of attention tasks here. The results however indicate a double dissociation; an abnormally persistent latent inhibition effect in high positive schizotypy individuals (Experiments 1 and 2) and a reduced learned irrelevance effect in high state anxious individuals (Experiments 3 and 4). The possibility that latent inhibition is non-attentional and the implications of these findings for associative models of attention and learning are explored. The aim of Experiments 5 and 6 were to explore the causal relationship between induced variations in anxiety (stress, relaxation or neutral mood) and learned variations in attention, using a less ambiguous measure of attention (compared to latent inhibition): learned irrelevance. Based on the findings from Experiments 3 and 4, a reduced attentional bias towards previously established predictive cues was expected in individuals induced with an acute state of anxiousness, relative to individuals induced with either a relaxed or neutral mood state. This pattern of results was observed but to a weaker extent than the previous experiments, suggesting that induced variations in anxiety do not have the same relationship with learning as naturally occurring variations in anxiety, as observed in Experiments 3 and 4. Further analyses revealed that the relationship between reduced learned irrelevance and anxiety was mediated by individuals who were also characterised by high levels of schizotypy, and by extension vulnerability to schizophrenia. Given the potential common underlying cognitive processes to both anxiety and schizophrenia, it seems likely that therapies which target the symptoms of anxiety (e.g., Attentional Bias Modification Treatment; ABMT) would be beneficial to individuals who have also been diagnosed with a psychotic disorder. This work represents the first attempt to investigate the independent effects of latent inhibition and learned irrelevance on schizotypy and anxiety, using refined tasks that minimised the contribution of either learning phenomenon on each other. How these learning tasks co-vary in patients with schizophrenia and clinically diagnosed anxiety however remains for future research to determine . At this juncture, the current findings lend support to the potential cognitive endophenotype status of learned irrelevance (considering its status as a less ambiguous measure of attention) and its continued use to provide a base for the development of relevant attentional bias modification treatments.