Stimulation and Recording of Compound Action Potentials in Lumbricus terrestris, Homarus Americanus and Cambarus bartonii nerves

Abstract

When an individual suffers nerve damage as a result of a stroke or severe trauma, their quality of life suffers greatly. In many cases, this can lead to paralysis of limbs due to peripheral nerve damage. To improve mobility for these patients, it is necessary to understand the extent to which they are impaired and to remedy it through specialized therapies, such as neurostimulation. Current research in the field of neurostimulation of model organisms, such as earthworms, lobster and crayfish, have demonstrated that it is possible to stimulate nerve bundles to propagate compound action potentials [12,15]. Once these action potentials are sent along nerves, it is possible to stimulate muscle contraction and with enough activation a patient could experience improved limb mobility over time. Ultrasound is a technique that has been widely used to stimulate and record neural activity [15]. The goal of this study is to investigate the feasibility of ultrasound as a method of producing consistent activation of nerves. This project will make use of ultrasound to observe changes that occur in the nerves of crayfish when a signal is being sent through but will also be coupled with electrical stimulation as a proof of nerve viability. Cross-sectional ultrasound images of the nerve will be taken at specific points to observe change in diameter as the action potential passes along the nerve. The diameter is expected to increase and decrease due to the flux of sodium ions [9]. Due to challenges difficulties on obtaining crayfish specimens and technical issues with the electrophysiological equipment, the intended goal of this study was not met. The protocols for an effective study were investigated however and will be incorporated into the experimental framework going forward.