Prenatal to postnatal transfer of motor skills through motor-compatible sensory representations

How can sensory-motor skills developed as a fetus transfer to postnatal life? We investigate a simulated reaching task by training controllers under prenatal conditions (i.e. confined space) and evaluating them based on postnatal conditions (i.e. targets outside of the confined training space). One possible solution is to identify a sensory representation that is easy to extrapolate over. We compared two kinds of sensory representations: world-centered sensory representation based on Cartesian coordinates and agent-centered sensory representation based on polar coordinates. Despite similar performance under prenatal conditions, controllers using agent-centered sensory representation had significantly better performance than controllers using world-centered sensory representation under postnatal conditions. It turns out that the success of the agent-centered sensory representation is (in part) due to being complementary to the action encodings. Further analysis shows that the action encodings (i.e. changes in joint angles) were highly predictive of the change in state when agent-centered sensory representation was used (but not world-centered). This suggests that a powerful strategy for transferring sensory-motor skills to postnatal life involves selecting a sensory representation that complements the action encodings used by an agent.