Though the book “Quantum Nano-Plasmonics” concerns a random-phase approximation model of plasmons in metallic nanoparticles, it finds unexpected application to soft plasmonics in bio matter. A wave type plasmon-polariton mechanism of the so-called saltatory conduction in myelinated axons is proposed.
For the first time since the 1960s, the wave kinetics of the ion plasmon-polariton model occurs consistent with the observations of signal kinetics in the white matter (saltatory conduction) of the brain and spinal cord and in the peripheral nervous system and with recent observations of micro-saltatory conduction C fibers of pain sensation. The traditionally used diffusion cable model results with by 2 orders of the magnitude too low signal speed.
A new explanation of the role of the myelin and the physical causes and mechanism of the action potential transmission defects in demyelination diseases (such as multiple sclerosis) has been also provided, other than previously assumed.
The proposed plasmon-polariton ion model to explain the so-called saltatory conduction in myelinated axons is in detail developed in the chapter XII of the monograph.
The neurophysiology puzzle of very quick saltatory conduction is of fundamental importance, as reducing the speed of this conduction by as little as 10% is mortal and the ionic current models gave the speed limit 2 – 3 m/s at most, versus 100 – 200 m/s observed in myelinated axons.
Due to the much larger mass of ions and their lower concentration in water electrolytes than of electrons in the metal, the plasmonic size of ionic finite confined systems is in the micrometer range, and the energies of ionic plasmons rapidly drop to the corresponding scale for living organisms. The new plasmonic saltatory conduction theory (chapter XII) in periodically myelinated neuronal axons is analytical, as is the plasmon-polariton theory in metallic nano-chains (chapter IX).
The concept of synchronized oscillations of ions propagating in the form of waves along periodically myelinated axons, i.e., the ion plasmon-polariton concept, is a novel proposition in the electrophysiology. Moreover, the plasmon-polariton kinetics of electro-signaling in myelinated axons reveals the difference in the mechanisms of electro-signaling of the gray and white structures of the brain and spinal cord. The point is that if there are nerve signals in myelinated axons actually generated by ionic plasmon-polaritons, then there is none external electromagnetic signature of this signaling as plasmon-polaritons do not radiate e-m waves. This is in contrary to electro-signaling in gray matter, where the ordinary ion currents produce an external e-m signature. This is consistent with the observations of EEG and MEG signals from the cortex of the brain, as well as with the inability to detect signals in the myelinated axons of the peripheral system by e-m wave methods, and only with the use of piercing electrodes. It may be related to another and so far unclear structural modeling in the gray matter in distinction to white matter and related to it, physical modeling of information transmission and identification in the cerebral cortex (chapter XII).
Acknowledgement: Supported by the Polish National Science Center project P.2018/31/B/ST3/03764