The space of actions - Neural circuits for transforming spatial representations into actions

I hear a familiar voice and I turn towards its source, I see a car approaching and I move away from it, I smell a cup of coffee and I reach for it. All these daily experiences are ultimately linked to our innate sense of space, we know where things around us are and how to interact with them. In other words, we are able to bind multisensory experiences into a coherent percept and allocate it in a meaningful spatial frame so to appropriately direct our actions. But how this multisensory binding occurs, how such a coherent mental spatial frame is constructed and how it is finally implemented to direct actions remain largely unresolved questions.
In recent years, we have begun to understand how animals encode spatial information in the form of allocentric maps, in the context of navigation. Similarly, spatially tuned actions such as reaching and orienting may rely on an egocentric map of peripersonal space, whose neural implementation becomes overt in the motor domain with the production of appropriate movement vectors. In comparison with navigational space, the neural basis of the encoding of peripersonal space ("the space within reach") as well as the neural mechanisms for its implementation into actions remain far less characterised. In this proposal I will assess the overarching hypothesis that this representation is routed in the motor domain and depends on motor execution. I hypothesise that brains construct cognitive and perceptual spatial representations by relying on the activity of networks involved in the planning and the control of three-dimensional bodily movements. In the words of Henry Poincaré, the French mathematician, "localising an object means representing to ourselves the movements that must take place to reach that object". Thus, in line with recent efforts to study perceptual and cognitive abilities as enactive processes (i.e. processes whose primary goal is to guide action), I propose and aim to test a kinetic, motor-routed theory of spatial cognition. I will argue that the most fruitful path to this goal is to start from the motor end of the problem, i.e. from the neuronal populations responsible for the generation of spatially tuned movements, and progressively move upstream to unravel circuits and computations responsible for their planning, selection and control.