Neural Engineering Seminar: In person, Wickenden 322, ÐÇ¿Õ´«Ã½
Speaker: Jonah Mudge
Advisor: Prof. Graczyk
Abstract:
When an amputation occurs, proprioception in the missing limb is lost and previously simple motor tasks can become much more difficult or even impossible to accomplish. Proprioception is the body’s sense of limb position and velocity in space and is a vital part of motor planning. Current cutting-edge neuroprostheses can elicit a rough sensation of proprioception using peripheral neural interfaces in people with limb loss. However, these devices do not yet fully replicate the proprioceptive acuity of an intact limb. One limiting factor is the gap in literature concerning the design and implementation of proprioception-specific stimulation paradigms. Many previous stimulation studies also do not account for the agonist-antagonist muscle interactions that are integral to natural proprioceptive sensation. Additionally, it is unclear what the primary mechanism of proprioceptive sensation through peripheral nerve stimulation is, whether it be direct muscle spindle fiber activation or off-target muscle activation. Previous data suggest an involvement of the contraction of the muscles of the residual limb in peripherally-stimulated proprioceptive sensations in the phantom hand, as proprioception and residual muscle EMG appear to be correlated. Further data demonstrate an effect of pulse frequency on proprioceptive stimulation. Based on these preliminary results, I propose methods for testing a new proprioceptive stimulation paradigm through the modulation of agonist and antagonist pulse frequency stimulation and the application of antagonist inhibition in people with unilateral upper limb loss. I further discuss a new surgical approach which my group used with a transhumeral participant who had extensive skin grafting on the residual limb, and finally I will present some of the first tactile and proprioceptive percepts that this participant experienced during preliminary testing.