The inability to communicate underlies one of the most disabling aspects of injury to the central nervous system, and includes the inability to perform rudimentary tasks such as flexing and extending ones'limb or moving a simple cursor on a screen. While the majority of studies thus far have targeted the intrinsic repair or regeneration of damaged areas of the central nervous system such as brainstem or proximal cervical spinal cord, alternative approaches for redirecting information between areas that remain functionally intact is largely unexplored. Work by our group and others has demonstrated that neuronal activity in cortical and subcortical areas responsible for motor control can accurately predict volitional movement intention, and that delivery of event-related electrical stimuli in areas responsible for motor production can reproducibly alter targeted limb movement. In the current study, we aim to extend these findings by systematically matching and altering motor intent with movement production in primates performing a motor directional task. To this end, we will obtain single-neuronal recording from the same subcortical areas shown to predict motor intention and use a similar system design to deliver electrical stimuli to the ventral spinal cord in order to approximate and alter movement production. Changes in neuronal activity will be examined over multiple trials as observed movements predicted by neuronal activity are made to either correspond or mismatch movements produced by spinal cord stimulation. These findings will provide a unique perspective into the individual roles that motor neuronal plasticity and spinal efferent activity play in adaptive motor control, and may offer valuable new insight into the development of prosthetic designs aimed at restoring volitional movement.
Motor deficit is among the most debilitating aspects of subjects suffering injury to the central nervous system. Despite continued efforts to develop treatments for patients with such injury, there remain few and often no options available for reconstituting volitional motor control. The proposed project aims to explore a novel approach for restoring motor communication that is based on a system design developed by our group for use in awake-behaving primates. The significant social impact of such devices has already been demonstrated with the emergence of cochlear, brainstem and retinal prosthetic implants, and may similarly provide significant benefit for patients with motor disability resulting from brainstem and proximal spinal cord injury.
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