In vivo characterization of regenerative peripheral nerve interface function.

Area of Science:

• Biomedical Engineering
• Neuroscience
• Prosthetics

Background:

• Regenerative peripheral nerve interfaces (RPNIs) utilize neurotized muscle grafts with electrodes for myoelectric signal recording.
• Previous studies confirmed the viability of RPNI constructs through evoked responses.
• In vivo characterization is essential for evaluating RPNIs as a control modality for prosthetic devices.

Purpose of the Study:

• To characterize in vivo electromyographic signal activity from RPNIs during locomotion.
• To assess the reliability of RPNI signals for predicting joint motion.
• To evaluate signal contamination from adjacent muscles.

Main Methods:

• RPNIs were surgically created in rats by grafting muscle to peripheral nerves and placing electrodes.
• In vivo electromyographic signals were recorded during treadmill walking and compared to control groups (intact muscle and denervated muscle).
• Signal amplitude, periodicity, and correlation with motion capture data were analyzed; a decoder was trained to predict joint motion.

Main Results:

• RPNI signals exhibited activity (1 mVPP) during walking and were quiescent (<0.1 mVPP) during standing.
• RPNI signals demonstrated periodicity and entrainment with gait cycles.
• A decoder achieved over 80% reliability in predicting bilateral ankle motion.

Conclusions:

• In vivo RPNI activity effectively encodes neural activation patterns linked to gait.
• Minimal signal contamination from adjacent muscles was observed, as evidenced by quiescent signals in the denervated group.
• The gait-entrained RPNI signals suggest transduction of centrally controlled neural activation patterns, suitable for prosthesis control.