  The collisions of two simultaneously generated impulses in the giant axons of
both earthworms and lobster propagating in orthodromic and antidromic direction
were investigated. The experiments have been performed on the extracted ventral
cords of Lumbricus terrestris and the abdominal ventral cord of lobster,
Homarus americanus, by using external stimulation and recording. The collision
of two nerve impulses of orthodromic and antidromic propagation didn't result
in the annihilation of the two signals contrary to the common notion that is
based on the existence of a refractory period in the well-known Hodgkin-Huxley
theory. However, the results are in agreement with the electromechanical
soliton theory for nerve pulse propagation as suggested by Heimburg and Jackson
(Proc. Natl. Acad. Sci. USA 102, 9790 (2005)).
