Description
Experimental
results have pointed out that the dendritic tree of spinal
motoneurons is not a passive resistive-capacitive network. Instead,
voltage-gated ionic conductances are present along the dendritic
tree
accounting for many nonlinear behaviors, such
as bistability (or a selfsustained firing following a brief
excitatory input) and plateau potentials. Our aim is to present
three new motoneuron models with a dendritic L-type calcium
conductance so that a persistent inward current (PIC) could
be generated, contributing to the genesis of phenomena observed in decerebrate cat
motoneurons. The models are of types S, FR, and FF with two
compartments each, one for the soma and another for
the dendritic tree. The geometric and electrotonic parameters were
based on a previous development from our laboratory in which
passive-dendrite motoneuron models were developed (Cisi and Kohn,
2008). Similarly to the passive-dendrite models, the soma
compartment comprises a sodium channel and a fast potassium channel,
both responsible for the genesis of action potential, along with a
slow potassium channel yielding the afterhyperpolarization (AHP). In our new models, an L-type
calcium channel was implemented in the denditic compartment and its
parameters were chosen according the properties of PIC and the
firing patterns of decerebrate cat motoneurons.
The
models were written in Matlab® (The MathWorks, Inc.) and here
you can download the source code (links on the right column). We
encourage you to use or to improve these models in accordance with the
distribution license, but without forgetting to cite the source.
Funding