Tracing axons of peripheral nerves in rats: a potential technique to study the equine recurrent laryngeal nerve

Retrograde Axonal Transport Property of Adeno-Associated Virus and Its Possible Application in Future

Gene therapy has become a treatment method for many diseases. Adeno-associated virus (AAV) is one of the most common virus vectors, is also widely used in the gene therapy field. During the past 2 decades, the retrograde axonal transportability of AAV has been discovered and utilized. Many studies have worked on the retrograde axonal transportability of AAV, and more and more people are interested in this field. This review described the current application, influence factors, and mechanism of retrograde axonal transportability of AAV and predicted its potential use in disease treatment in near future.

Neural signal recording and processing in somatic neuroprosthetic applications. A review

Neurointerfaces have acquired major relevance as both rehabilitative and therapeutic tools for patients with spinal cord injury, limb amputations and other neural disorders. Bidirectional neural interfaces are a key component for the functional control of neuroprosthetic devices. The two main neuroprosthetic applications of interfaces with the peripheral nervous system (PNS) are: the refined control of artificial prostheses with sensory neural feedback, and functional electrical stimulation (FES) systems attempting to generate motor or visceral responses in paralyzed organs. The results obtained in experimental and clinical studies with both, extraneural and intraneural electrodes are very promising in terms of the achieved functionality for the neural stimulation mode. However, the results of neural recordings with peripheral nerve interfaces are more limited. In this paper we review the different existing approaches for PNS signals recording, denoising, processing and classification, enabling their use for bidirectional interfaces. PNS recordings can provide three types of signals: i) population activity signals recorded by using extraneural electrodes placed on the outer surface of the nerve, which carry information about cumulative nerve activity; ii) spike activity signals recorded with intraneural electrodes placed inside the nerve, which carry information about the electrical activity of a set of individual nerve fibers; and iii) hybrid signals, which contain both spiking and cumulative signals. Finally, we also point out some of the main limitations, which are hampering clinical translation of neural decoding, and indicate possible solutions for improvement.

Quantification of human upper extremity nerves and fascicular anatomy

INTRODUCTION

In this study we provide detailed quantification of upper extremity nerve and fascicular anatomy. The purpose is to provide values and trends in neural features useful for clinical applications and neural interface device design.

METHODS

Nerve cross-sections were taken from 4 ulnar, 4 median, and 3 radial nerves from 5 arms of 3 human cadavers. Quantified nerve features included cross-sectional area, minor diameter, and major diameter. Fascicular features analyzed included count, perimeter, area, and position.

RESULTS

Mean fascicular diameters were 0.57 ± 0.39, 0.6 ± 0.3, 0.5 ± 0.26 mm in the upper arm and 0.38 ± 0.18, 0.47 ± 0.18, 0.4 ± 0.27 mm in the forearm of ulnar, median, and radial nerves, respectively. Mean fascicular diameters were inversely proportional to fascicle count.

CONCLUSION

Detailed quantitative anatomy of upper extremity nerves is a resource for design of neural electrodes, guidance in extraneural procedures, and improved neurosurgical planning. Muscle Nerve 56: 463-471, 2017.

Topographical distribution of motor fascicles in the sciatic-tibial nerve of the rat

Knowledge of the intraneural topography of peripheral nerves may help to improve nerve repair after injuries and the selectivity of neural interfaces. We studied the fascicular pattern of motor fibers of the rat sciatic-tibial nerve. We carried out an anatomical dissection of the muscular tributaries of the tibial nerve in the leg. Immunohistochemistry against choline acetyltransferase was used to identify motor axons. Retrograde tracing allowed localization of the muscular fascicles at proximal levels of the sciatic trunk. The distribution of motor fibers in transverse section of the tibial nerve is not homogeneous; two clusters were identified, each one containing fibers of functionally related muscles. Retrograde tracing allowed for the identification of motor fascicles, each one well localized along the sciatic nerve. In the rat there is a somatotopic organization of the sciatic nerve, with muscular fascicles maintaining the same relative position along the entire nerve.