Interfacing the peripheral nervous system: towards the development of a bidirectional neural communication

The human hand executes incredibly sophisticated tasks as the result of the synergistic interplay between motor and sensory functionalities. The hand loss is a life changing physiological and psychological trauma, which degrades significantly every day activities of people. The ideal prosthesis should restore sensory and motor capabilities to amputees. Current available devices, however, provide users with a restricted gamma of movements and without sensory feedback and, as a consequence, are often abandoned. In the last 20 years, the fascinating possibility to access the human peripheral nervous system, for the development of natural and effortless man-machine interfaces, has been proposed. However, presently, there is a gap between the proofs-of-concept that have been shown and reliable and efficient assistive bidirectional devices. Main reason for it is a limited basic understanding both about: i) the nature of the efferent peripheral signals that could be used as the signal triggering the actuation of a neuroprosthesis, and ii) about the effects of the afferent neural stimulation, and the way to use it in a sophisticated manner. Present thesis is aiming to advance the basic knowledge and to introduce novel findings into the bidirectional neuroprosthesis implementation. Indeed it presents novel strategies for decoding subjects’ voluntary motor intention from efferent fibers firing recordings, and for restoring sensory feedback in amputees by stimulating the afferent fibers in optimal way to transmit the effective sensory feedback to the brain. The design of these algorithms has been inspired by the natural mechanisms by which the peripheral nervous system drives hand movements and the physiological sensations coming from interaction with objects and their manipulation