Rima Budvytyte*,
Alfredo Gonzalez-Perez, Lars D. Mosgaard, Tian Wang and Thomas
Heimburg
Technical University of
Dresden.
Title: Action Potential Collision in the Invertebrates Nerves.
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 action potentials
propagating in the medial giant axons of sensory nerve bundle present in
walking legs of lobster 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). For comparison, collision
experiments were done in the liquid chamber, where nerves were always
immersed and were surrounded by saline solution.
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].