Penetration of Action Potentials during Collision in the Medial Giant Axon of Invertebrates

Abstract

It is generally accepted that the collision of two action potentials coming from opposite directions is produced by the mutual annihilation of both signals. The experimental confirmation of this effect was shown by Tasaki in 1949 [1] and experiment is in agreement with the predictions of Hodgkin-Huxley model for action potential propagation [2].In the current work we performed an analogous experiments to these made by Tasaki but using earthworms Lumbricus terrestris and lobsters Homarus americanus as an animals models. The collision of two simultaneously generated impulses propagating in orthodromic and antidromic directions were investigated. Also, the collision of compound of action potentials in the medial giant axons of sensory nerve bundle present in walking legs of lobster propagating were observed too. The experiments have been performed in the extracted ventral cords and nerve bundles of walking leg of lobster by using external stimulation and recording. The stimulation voltage was used as a tool to selectively stimulate the small neuronal population of giant axons (5 to 6 neurons).Surprisingly, the collision of two impulses generated simultaneously, does not result in their annihilation. Instead, they penetrate each other and emerge from the collision without material alterations of their shape or velocity [3]. These results were published in Physical Review Letters X (2014) and are not consistent with expectations from the established HH model. But the findings, could be explained if nerve pulses are “electromechanical” waves - solitons, as suggested by Heimburg and Jackson [4].1.Tasaki I. Bioch. Bioph. Acta, 1949;3:494-497.2. Hodgkin A.L. and Huxley A.F. J. Physiol., 1952;177:500-544.3. Gonzalez-Perez A., Budvytyte R., Mosgaard D.L., Nissen S., Heimburg T. P . Phys. Rev. X., 2014;4:031047.4. Heimburg T. and Jackson A.D.. Proc. Natl. Acad. Sci. USA., 2005;102:9790-9795.