Computational studies of decision-making and planning in the primate brain

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How does the brain make decisions about actions? One hypothesis suggests that when we look at the world, part of our brain processes the sensory information in terms of the actions which are currently possible. Neural representations of these actions then compete against each other until one is chosen to guide overt performance. In other words, behavior is a constant battle between the demands and opportunities for action which the world presents to us.      In my laboratory, I investigate this broad hypothesis through two approaches. On one hand, I conduct experiments utilizing multi-electrode recording, functional imaging, and behavioral analysis. On the other, I develop computational models which describe the mechanisms by which the nervous system implements decision-making and planning. These models are expressed through mathematical equations which are implemented as computer programs that simulate a wide range of neurophysiological and behavioral phenomena. Using these models, we can try to understand brain operation at a mechanistic level, and even to predict how it should behave in various novel situations.      In this NSERC application, I am requesting funds to support my computational modeling research program. Recently, I have developed a mathematical model which explains a variety of neural and behavioral results on primate decision-making and planning. This model provides the starting point for a long-term research program in computational neuroscience. It will involve a series of projects, including: exploring the mechanisms for learning the transformation of sensory information between different representational reference frames (e.g. from visual coordinates to motor coordinates); extending the model to adapt through reinforcement learning; and giving the model the capacity to discover arbitrary stimulus-response association rules. It is hoped that these computational projects will evolve into a long-term research program that will lead to new insights into the brain mechanisms underlying voluntary behavior.