The social brain : how social stimuli are translated into neuroendocrine signals

Tese de doutoramento, Biologia (Ecofisiologia), Universidade de Lisboa, Faculdade de Ciências, 2014Animals continuously fine-tune the expression of social behaviors according to daily fluctuations on their social environment. But how does the social environment influence brain and behavior and what are the underlying physiologic, molecular and genetic mechanisms? Behavioral flexibility depends on neural plasticity of circuits underlying social behavior, which is achieved by social regulation of brain gene expression. Different neurogenomic states emerge in response to different external stimuli and switches between states are orchestrated by signaling pathways interfacing the social environment and the genotype. The goal of this thesis is to understand how social environment influences brain genomic transcription: (1) during a complex social interaction in zebrafish and (2) after stimulation with context-specific social olfactory stimuli in the Mozambique tilapia. Zebrafish, Danio rerio, has long been used as a model organism in developmental biology and genetics. Despite of their limited behavioral repertoire, the available genetic tools make it a promising model for the study of social behavior. In contrast, the Mozambique tilapia, Oreochromis mossambicus, has a rich behavioral repertoire in which visual and chemical information are conveyed to conspecifics, although having limited brain anatomy information and less genetic tools available. Our research suggests that the outcome of a single social interaction in zebrafish has consequences for subsequent behavior and significant impact on their brain transcriptome. These responses to social interactions seem to involve cognitive appraisal of stimuli, since the objective structure of the event does not trigger a genomic response but rather the appraisal the individual makes of the event. In tilapia, different chemical social cues not only affect neural activity of the olfactory epithelium but also elicit specific patterns of gene activation in brain areas related to olfactory processing. This reinforces the idea of an extensive transcriptional plasticity of teleost genomes, especially in response to rapid changes in social environment.Fundação para a Ciência e a Tecnologia (FCT, SFRH/BD/40976/2007, Programa Operacional Ciência e Inovação 2010 - POCI 2010

Optimization based on genetic algorithms for image registration

Diplomová práce se zabývá globálními optimalizačními metodami a jejich využitím při registraci medicínských obrazů. Hlavní cíl spočívá ve vytvoření genetického algoritmu a testování jeho funkčnosti na syntetických datech. Kromě testovacích funkcí a obrazců byl algoritmus podroben i skutečným medicínským snímkům. K tomuto účelu se vytvořilo grafické uživatelské prostředí s volbou parametrů podle aktuální potřeby. Přidáním iterační gradientní metody se algoritmus stal hybridním genetickým algoritmem.Diploma thesis is focused on global optimization methods and their utilization for medical image registration. The main aim is creation of the genetic algorithm and test its functionality on synthetic data. Besides test functions and test figures algorithm was subjected to real medical images. For this purpose was created graphical user interface with choise of parameters according to actual requirement. After adding an iterative gradient method it became of hybrid genetic algorithm.