Solitary electromechanical pulses in Lobster neurons

Abstract

Investigations of nerve activity have focused predominantly on electrical phenomena. Nerves, however, are thermodynamic systems, and changes in temperature and in the dimensions of the nerve can also be observed during the action potential. Measurements of heat changes during the action potential suggest that the nerve pulse shares many characteristics with an adiabatic pulse. First experiments in the 1980s suggested small changes in nerve thickness and length during the action potential. Such findings have led to the suggestion that the action potential may be related to electromechanical solitons traveling without dissipation. However, they have been no modern attempts to study mechanical phenomena in nerves. Here, we present ultrasensitive AFM recordings of mechanical changes on the order of 2 - 12 Å in the giant axons of the lobster. We show that the nerve thickness changes in phase with voltage change. When stimulated at opposite ends of the same axon, colliding action potentials pass through one another and do not annihilate. These observations are consistent with a mechanical interpretation of the nervous impulse.

9 pages, 4 figures

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• Mechanical Surface Waves Accompany Action Potential Propagation
• The thermodynamics of general anesthesia
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Cited by in corpus (17)

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• Electromechanical coupling of waves in nerve fibres
• A simple mathematical model inspired by the Purkinje cells: from delayed travelling waves to fractional diffusion
• On cell surface deformation during an action potential
• The thermodynamic soliton theory of the nervous impulse and possible medical implications
• The free energy of biomembrane and nerve excitation and the role of anesthetics
• Linear nonequilibrium thermodynamics of reversible periodic processes and chemical oscillations
• The Heat of Nervous Conduction: A Thermodynamic Framework
• Phase transitions in biological membranes
• The excitable fluid mosaic
• On solutions of a Boussinesq-type equation with displacement-dependent nonlinearity: a soliton doublet
• The effect of stretching on nerve excitability
• Mathematics of nerve signals
• Mechanical waves in myelinated axon wall
• The mechanical properties of nerves, the size of the action potential, and consequences for the brain
• Primary and secondary components of nerve signals
• The important consequences of the reversible heat production in nerves and the adiabaticity of the action potential