Prioritizing saccades according to their relative costs and benefits

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Should I stay or should I go now? The clash between changing and staying the course is a very familiar choice in our everyday lives be it a trivial choice such as leaving a social event, or a 'big life choice' such as leaving one's job. This project hypothesizes that this type of decision underpins our most frequent choice: where to look next. On average, we move our eyes in discrete jumps (saccades) twice as often as we beat our hearts. Although this feels very automatic, each movement involves a mostly unconscious decision of when to move. Should I continue to exploit my maximum resolution vision on my current focal point, or is now the time to explore new regions of space? There are also costs as well as benefits to moving, since the visual disturbance during the movement (think major camera shake) is perceptually suppressed, meaning we are mostly blinded during the 10% of our waking lives spent making these movements. This project tests the novel hypothesis that saccade choices are governed by an evaluation of their relative costs and benefits, allowing us to prioritize better choices over worse ones. The same framework will be applied to test if the problems in initiating saccades seen in Parkinson's disease are due to a breakdown in a cost/benefit evaluation. By understanding how such a simple, but pervasive, decision process is driven, the investigators expect to reveal more fundamental and general principles of decision making in the brain. Understanding how the brain achieves optimal behavior in dynamic environments, more broadly, is a critical issue in neuroscience and for intervening when this process goes awry. Clarifying these processes in Parkinson's disease could lead to better diagnostic tests of disease onset and progression.