TITLE:
Bistability in Ephaptic Coupling as a Possible Memory Element Explored through a Colloid Interptation of Stereocilia Bistability
AUTHORS:
Michelangelo Rossetto
KEYWORDS:
Ephaptic, Hair Cell, Stereocilia, Colloid, Bistability, Memory
JOURNAL NAME:
Journal of Electromagnetic Analysis and Applications,
Vol.7 No.3,
March
25,
2015
ABSTRACT: When the processes
of neurons are in close proximity they effectively couple to each other in a
process termed Ephaptic coupling. This coupling occurs without the membranes
touching when the space between them is some tens of nanometers. If the
intra-membrane spacing has a mechanical bistability, which moves the membranes
closer and further apart, the Ephaptic coupling will be turned on and off
allowing one neuron to read, or not read the content of the other. This paper
explores the possibilities of bistable ephaptic memory element by a study of an
analogous system that operates at a much larger scale, the Stereocilia of the
hair cell. Published measurement of hair cell Stereocilia force/displacement
function shows both a negative slope region in the displacement function and
tendency to express bistability. We show here how this negative slope region
can arise through the exigency of colloid forces. An explanation of Colloid
Theory, presented in a graphic form, shows how a colloid force function can be
modified to match the measured hair cell cilia force function. The colloid
force function is modified by a limiting function resulting from Stereocilia
side links, structural details that tie together the hair cell Stereocilia
clusters. Understanding how a limited, simple behavior such as Stereocilia
bistability functions may point to a more general understanding of how
bistability may underlie other areas of living organisms such as memory and
computation.