title: Functional recordings from awake, behaving rodents through a microchannel based regenerative neural interface.
abstract: OBJECTIVE
  Neural interface technologies could provide controlling connections between the nervous system and external technologies, such as limb prosthetics. The recording of efferent, motor potentials is a critical requirement for a peripheral neural interface, as these signals represent the user-generated neural output intended to drive external devices. Our objective was to evaluate structural and functional neural regeneration through a microchannel neural interface and to characterize potentials recorded from electrodes placed within the microchannels in awake and behaving animals.
  
  
  METHODS
  Female rats were implanted with muscle EMG electrodes and, following unilateral sciatic nerve transection, the cut nerve was repaired either across a microchannel neural interface or with end-to-end surgical repair. During a 13 week recovery period, direct muscle responses to nerve stimulation proximal to the transection were monitored weekly. In two rats repaired with the neural interface, four wire electrodes were embedded in the microchannels and recordings were obtained within microchannels during proximal stimulation experiments and treadmill locomotion.
  
  
  RESULTS
  In these proof-of-principle experiments, we found that axons from cut nerves were capable of functional reinnervation of distal muscle targets, whether regenerating through a microchannel device or after direct end-to-end repair. Discrete stimulation-evoked and volitional potentials were recorded within interface microchannels in a small group of awake and behaving animals and their firing patterns correlated directly with intramuscular recordings during locomotion. Of 38 potentials extracted, 19 were identified as motor axons reinnervating tibialis anterior or soleus muscles using spike triggered averaging.
  
  
  CONCLUSIONS
  These results are evidence for motor axon regeneration through microchannels and are the first report of in vivo recordings from regenerated motor axons within microchannels in a small group of awake and behaving animals. These unique findings provide preliminary evidence that efferent, volitional motor potentials can be recorded from the microchannel-based peripheral neural interface; a critical requirement for any neural interface intended to facilitate direct neural control of external technologies.
authors.affiliation: Department of Neurology, Emory University School of Medicine, 550 Peachtree Street NE, 9th Floor MOT, Atlanta, GA 30308, USA. Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory School of Medicine, 1760 Haygood Drive NE, Atlanta, GA 30322, USA.
authors.forename: Russell K
authors.initials: RK
authors.lastname: Gore
authors.forename: Yoonsu
authors.initials: Y
authors.lastname: Choi
authors.forename: Ravi
authors.initials: R
authors.lastname: Bellamkonda
authors.forename: Arthur
authors.initials: A
authors.lastname: English
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D004567:Electrodes, Implanted; D019544:Equipment Failure Analysis; D005260:Female; D048091:Guided Tissue Regeneration / Q000295:instrumentation*; D018670:Monitoring, Ambulatory / Q000295:instrumentation*; D009416:Nerve Regeneration / Q000502:physiology*; D009431:Neural Conduction / Q000502:physiology; D011474:Prosthesis Design; D051381:Rats; D011917:Rats, Inbred Lew; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D054457:Tissue Scaffolds