Relatore: Giandomenico Iannetti, Professor of Neuroscience, Istituto Italiano di Tecnologia (IIT), University College London (UCL)

Interactions occurring within the space near the body are studied in a wide range of disciplines, from ethology to philosophy. Indeed, many behavioural responses are enhanced when stimuli occur near the body. This makes evolutionary sense: a predator within striking distance is more relevant than one farther away. Neuroscientific studies in primates have suggested a physiological foundation for such behavioural modulations, leading to the concept of peripersonal space (PPS). But what is precisely meant when referring to PPS? Predominant conceptual frameworks describe peripersonal space (PPS) as a single, distance-based, in-or-out zone within which stimuli elicit enhanced neural and behavioural responses. In this talk I will first argue that this intuitive framework is contradicted by neurophysiological and behavioural data. I will then show that PPS measures do not reflect representations of stimulus proximity, but rather the behavioural relevance of actions aiming to create or avoid contact between objects and the body. This reconceptualisation of PPS as a set of graded egocentric fields describing the value of contact actions takes into account mainstream theories of action selection and behaviour. I will finally demonstrate that egocentric response fields arise naturally from two simple and plausible assumptions about living agents: 1) they experience reward when they contact objects in the environment, and 2) they act to maximise reward.
Egocentric peripersonal fields provide building blocks that together create a short-term map of the world near the agent in terms of its future states, analogous to the long-range allocentric fields of hippocampal place and grid cells. Together, allocentric and egocentric maps allow efficient interactions with a changing environment across multiple spatial and temporal scales.