ProprioMaps · The somatotopic organization of proprioception: from bold activity to single neurons up to new rehabilitative tools

Proprioception is a hidden sensory modality and, despite its strong role in motor control, it has been almost neglected. The ProprioMaps project has the overall goal of clarifying the neural mechanisms of proprioception, and its plasticity, to develop a proof of concept for motor rehabilitation. It will avail of the unique opportunity of comparing results in humans (fMRI and fNIRS) with neuron activity recorded in monkeys, providing an extensive understanding of the phenomenon. I will pursue this ambitious goal through three interleaved objectives (Obj). (Obj1) I will adopt fMRI topographic methods to define proprioceptive/motor maps (henceforth called body maps) in the brain of four different populations: healthy, hemiplegic (outgoing and ingoing phases), low vision (secondment), and amputees (placement) people. The involvement of these populations will provide important knowledge concerning body map plasticity. Then, using a visual proprioceptive disparity task and computational approaches (Obj2), I will investigate how these body maps integrate visuo-proprioceptive input during a hand reaching task (fMRI and fNIRS) and during walking (fNIRS). Finally (Obj3), I will decode neurons activity of monkeys performing reaching and grasping tasks with and without visual input, to understand the possibility of predicting the type of action and sensory modality used to perform it. Overall, results will tell us whether vision is able to act as a sensory substitution for proprioception and will elucidate the neural correlates of this mechanism. This sensory substitution concept will be developed in an application that will add proprioceptive information to myoelectric prostheses. In summary, the ProprioMaps project will provide an extensive study of the proprioceptive network and its processes. Furthermore, it will lead to a proof of concept of a sensory substitution application for motor rehabilitation that will be further exploited to develop a sensory substitution device.