Relatório Anual 2010 - Fundação Champalimaud

their behaviour according to the opponent’s strategy and the relative sizeof the payoff resulting from cooperative or defective moves, we now aim atdissecting the mechanisms underlying the decision-making process duringsuch social dilemma games. We have designed and set-up an automatedmaze to study the behavior of rats in different social dilemma games, suchas the Stag Hunt and the Snow drift game, which allow for dissection of thefactors that govern cooperation between two rats.Mechanism of vicarious fearThis project aims at investigating the mechanisms underlying vicarious fearin rats. It has been shown that rats can learn from social interactions, howeverthe mechanisms underlying this form of learning are poorly understood.In this project we are focusing on social transmission of fear. In collaborationwith Dr. Christian Keysers, we have developed a paradigm for studyingvicarious fear in rats. We have found that a rat will show vicarious fearwhen observing a conspecific being shocked, provided that it has had priorexperience with shock. This finding suggests that vicarious freezing in ratsis empathic in nature. Furthermore, we found that the rat being shocked willfreeze more in the presence of an experienced observer than in the presenceof a naïve one and that the amount of freezing is correlated with the numberof alarm calls emitted by the two rats.Michael OrgerVision to ActionGroup membersClaudia Feierstein (Postdoctoral Fellow)João Marques (PhD Student)Our brains process and integrate sensory information,experience, and internal states to plan and executeappropriate behavioural responses. Understanding howthese processes are implemented in neural circuits isa major goal of contemporary science. We address thisquestion using visuomotor responses in zebrafish, whosebrain has the same basic vertebrate organization as ours,but is numerically about a million times less complicated.Small and transparent, zebrafish are uniquely well suitedto take advantage of recent advances in optical and geneticmethods for exploring neural function.Figure 2 – Structure and function of neural circuits in thezebrafisha) Projection of two photon image stack of motor controlneurons in the zebrafish brainstem. b) Optical section ofpanneural GCaMP fish with superimposed color map ofdirection preference recorded by functional imaging (seeinset look up table). c-d) Stable GFP expression driven inspecific neurons in the mid/hindbrain using conservedzebrafish enhancer sequencesFC Relatório Anual 2010 30