SURROUNDED

A specific network of sensorimotor neurons (in parietal, premotor and subcortical areas) has evolved to represent the immediate surrounding of the body, also known as peripersonal space (PPS). Whether we see in PPS a snake to avoid, an apple to grasp, or an angry person to avoid, it has a unique direct significance. However, we constantly navigate in rich environments, surrounded by multiple objects and congeners, many of which that have no special relevance for us. How, then, does the brain operate? We can contrast two alternatives: (i) Proximity account: Proximity suffices to give a unique significance to stimuli and thus, to trigger PPS mechanisms because everything that is close-by matters. PPS processing is constantly activated. Factors other than proximity have only a modulatory effect. (ii) Proximity+ account: Proximity does not suffice because the computations underlying PPS have neural, energetic, and cognitive costs. To manage costs, only some of our nearby stimuli gets high enough priority values to turn PPS processing ON. . In this truly multidisciplinary project we argue that there is a trade-off between what one gains thanks to PPS processing and what one loses in exchange. We propose a new account that assumes that it is only in some circumstances that PPS processing is worth the cost (Proximity+). We shall theoretically and experimentally investigate what is required to give significance to the stimuli in our immediate surrounding to switch on peripersonal processing, including salience, valence, and social relevance, using the ecological set-up provided by the Lyon platform Neuro-Immersion for immersive virtual reality. Whereas most studies on PPS have focused on negative stimuli, such as threats, we shall also test positive stimuli, and more specifically food, which has a unique value for survival and which has been relatively neglected in the field of perception.