FL - Dissertações de Mestrado
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- An unsupervised generative strategy for detection and characterization of rare behavioural events in mice in open fiel to assess effect of optogenetic activation of serotonergic neurons in the dorsal raphe nucleiPublication . Soares, Lucas B. Nicolosi; Mainen, Zachary F; Correia, LuísThe purpose of our work is to provide an unsupervised deep learning tool that uses predictability of behavior as a meaningful metric to quantify the di erences between normal and abnormal behavior in the context of an experiment where mice receive optogenetic stimulation in their serotonergic neurons located in the dorsal raphe nuclei. We use generative adversarial networks to learn, on a training subset of the videos, a baseline behavioral repertoire by predicting future frames from subsequent frames in the past. By de ning a predictability index as dissimilarity between the quality of the generated prediction and the ground truth frame, we are able to determine in which frames a behavior not observed by the model during training is performed and therefore, we can detect the presence of stimulation by only analysing the uctuations of this index that indicate when the mouse is performing behaviors that are not present in the learnt baseline.
- A memória como condição para o sucesso da cooperaçãoPublication . Sousa, David; Correia, Luís; Garcia-Marques, LeonelCooperar é um dilema que em várias circunstâncias implica um investimento num futuro incerto, que pode não ter retorno caso o parceiro ou os parceiros de interacção sejam oportunistas. Cooperar é o ideal para o grupo mas não cooperar compensa a curto-prazo. É a decisão racional, que maximiza o ganho pessoal em sacrifício do bem comum. Contudo, se essa estratégia for dominante pode dar-se a tragédia do bem comum. A verdade é que a cooperação observa-se a todos os níveis de organização biológica em coexistência com o egoísmo, possivelmente porque terá evoluído para prevenir a tragédia. E se for esse o caso, é possível que a cognição humana tenha evoluído ao serviço dos mecanismos que sustentam a cooperação para a sobrevivência, nomeadamente o mecanismo de reciprocidade, que ao nível cognitivo implica memória e linguagem para o controlo pessoal e social do oportunismo, e ao nível social e psicológico consiste num sistema complexo de normas morais, julgamento, sanções e emoções sociais para a regulação de comportamento. Neste trabalho apresenta-se um modelo multi-agente desenvolvido com o objectivo de avaliar a importância da memória e da linguagem para a construção de uma rede social de reciprocidade que permita sustentar a cooperação em condições adversas à sobrevivência, e executa-se uma série de experiências que demonstram que a cooperação resolve a tragédia do bem comum no tempo de vida dos agentes e que a cognição é necessária à cooperação. O tipo de modelo desenvolvido permitirá no futuro investigar a questão principal que motiva este estudo: Será que condições ecológicas adversas pressionam selectivamente a evolução da cognição, por meio da necessidade de cooperação para a sobrevivência?
- Motor imagery and music : the influence of music on mental rotation tasks in the light of the embodied cognition theoryPublication . Castellar, Fernando Dantas; Yates, David; Mendes, Pedro Alexandre DuarteThe Embodied Cognition Theory (ECT) has become a hot topic in Cognitive Science, providing the investigation of cognitive phenomena with food for thought through a wide range of empirical findings. Two core claims from ECT were investigated in the present study: 1) the non-neural parts of an organism’s body play a constraining role in cognition; and 2) all concepts (strong embodiment) or some concepts (weak embodiment) are grounded in modality-specific areas of the brain. In line with 2), studies on mental imagery of bodily-related movements (henceforth: motor imagery) suggest that we use motor concepts grounded in modality-specific areas of the brain (the motor cortices) when we carry out motor simulations of our own body (Jeannerod, 2006), including in cognitive tasks such as MR of bodily-related pictures (Parsons et al., 1995). Also, studies in music perception have correlated the cortical activation of motor areas of the brain with rhythmic perception, varying in degree of activation according to the rhythmic complexity of a stimulus (Grahn & Brett, 2007). Finally, these assumptions predict the Mozart Effect, which consists of subjects’ temporary enhancement in performance at spatial-temporal reasoning tasks, including MR tasks (Rauscher, Shaw & Ky, 1993). Based on these assumptions, it was investigated whether subjects’ (N= 36) performance at a MR of bodily-related pictures would differ after exposure to musical pieces with different levels of rhythmic complexity and a control condition (silence). Results show that, although subjects’ performance was affected by the biomechanical constraints of their own bodies, suggesting that the body biomechanics play a constraining role in cognition, the Mozart Effect was not observed, suggesting that either 1) weak conceptual embodiment may not be true for motor imagery, and motor concepts are not grounded in modality-specific brain areas, 2) the musical samples used in the present study were not adequate to elicit sufficient cortical activation that would eventually result in performance enhancement, or 3) the Mozart Effect is due to reasons other than cortical activation of modality-specific brain areas, such as increase in arousal/mood levels or an artefact of subjects’ preference for a stimulus (Chabris, 1999). It is suggested that future research employs brain-mapping techniques, such as Positron Emission Tomography (PET Scan), Functional Magnetic Resonance Imaging (fMRI), or Electroencephalogram (EEG) to strengthen one or more hypotheses that account for the failure in observing the Mozart Effect in this study by identifying which brain areas were involved during the listening task and/or the MR of bodily-related pictures.
- Neuroscientific, psychological and clinical-philosophical approaches to voice-hearing : a critical systematic reviewPublication . Stanke, Franziska Anne; Pinheiro, Ana; Gener, AlexenderTackling the complexity of auditory verbal hallucinations (AVHs) or voice-hearing phenomena in schizophrenia requires an interdisciplinary approach for their better understanding, and ultimately for their treatment. One initial, but far reaching obstacle on the way to an appropriate understanding of voice-hearing is that there is no consensus on how such phenomena are best conceptualised. Given the various dimensions in which voice-hearing experiences can be described (e.g., audibility, personification, relationality) it is not obvious which of them constitute core features of voice-hearing. In the present thesis, it is proposed that the experience of a communication moment is a promising candidate for such a core feature. Moreover, studies from the areas of neuroscience, psychology, as well as clinical philosophy are systematically reviewed in order to examine how voice-hearing is conceptualised and studied in these disciplines. Methodological, as well as conceptual shortcomings of these approaches are critically discussed. Whereas neuroscientific accounts of voice-hearing have focused on self-monitoring accounts, clinical-philosophical accounts of voice-hearing in schizophrenia have focused on general alterations of experience as basis for the occurrence of voice-hearing. Psychological approaches to voice-hearing stress its relational nature. Such accounts have largely been developed separately and their compatibility is not obvious, also because of differing metaphysical assumptions of different disciplines. It is proposed that a phenomenological-ecological standpoint may be valuable for the contextualisation of results regarding voice-hearing from different disciplines, avoiding the pitfalls of reductionist conceptions of voice-hearing. Practical implications for an interdisciplinary research of AVHs are also derived.
- Sweet dilemma of mine : how glucose levels influence cooperation after a crisis?Publication . Casqueiro, Maria Inês Oliveira; Garcia-Marques, Leonel; Sebastião, AnaDiariamente tomamos decisões complexas que requerem tempo e esforço que não podemos despender. Compreender como decidimos em ambientes ambíguos com recursos cognitivos limitados torna-se essencial para todos nós. Este trabalho surge da intersecção da Psicologia e Neurociência, analisando a tomada de decisão cooperativa. O objectivo é analisar como diferentes níveis de glicemia influenciam a cooperação depois de um evento crítico. Aqui, a crise é operacionalizada como uma crise de recursos num dilema social. Esta investigação torna-se a primeira a explorar a relação entre glucose e cooperação pós-crise. A nossa amostra consiste em 47 adultos voluntários de ambos os géneros, recrutados através do método de amostragem snowball. Usámos uma tarefa commons dilemma com duas condições de perigo de extinção de recurso (High vs Low Danger) e manipulámos os níveis de glicemia dos participantes administrando uma bebida rica em ou sem açúcar. Desta forma, a experiência consistiu num design factorial 2 Glucose (glucose vs placebo) x 2 Danger (High vs Low), inter-sujeitos. Os dados sugerem que participantes com níveis mais elevados de glucose sanguínea são mais cooperativos num contexto pós-crise (e não antes) e principalmente quando há maior perigo de extinção de recursos (condição High Danger). Estes resultados implicam que a glucose sanguínea influencia processos de tomada de decisão, replicando estudos anteriores; e que pode influenciar as decisões cooperativas em alguns contextos. Assim, sugerimos que níveis de glicemia mais baixos estão associados a uma redução dos recursos cognitivos o que promove um processamento cognitivo intuitivo, estimulando o uso de certas heurísticas sociais. Sugerimos que investigações futuras analisem quais as heurísticas sociais mais salientes em diferentes cenários pós-crise, sob diferentes níveis de glicemia. A combinação de métodos da Psicologia, Neurociência e Computação, integrando assim diferentes áreas da Ciência Cognitiva, permitirá continuar a expandir o nosso conhecimento sobre a tomada de decisão cooperativa.
- The incoherent mind : analysis of mind, brain and split-brain data in search of a countable number of mindsPublication . Brito, Tiago Machado de; Yates, David; Hopkins, JimSplit-brains, patients who have undergone a corpus callosotomy – the severing of the corpus callosum – have been targets of study for several decades, due to strange behavioral phenomena that they reveal. In experimental conditions, in which different information can be exclusively provided to each hemisphere of the brain, they appear to be able to act as if two distinct persons. This phenomena have left many investigators from various areas of research in awe, unable to explain how such strange occurrences could originate from a brain much like our own. However, here I argue that, not only can a normal brain account for the split-brain phenomena (given their structural changes), but that analyzing the problem from a different standpoint – that of considering mental incoherencies – we can start seeing mental coherence, not as a necessary property of a mind, but as a necessary property of a set of conscious states; and since split-brain patients seem to have a partially incoherent consciousness, where an incoherent conscious stream arises under experimental situations, no single or set of co-conscious conscious states in each hemisphere reveals incoherencies, but rather, the mind as a whole does. As such, and in accordance with the Bayesian Brain theory, I stand in the present work for an incoherent, single-mind hypothesis to the question of how many minds a split-brain patient has – a question that has closely followed the split-brain debate since its birth.