Single Cell Scale
For coupling between EP and deformation three distinct cellular mechanisms are implemented which are chosen on the fly depending on the myofilament chosen.
Activation-based coupling with phenomenological myofilament models
These myofilament models trigger a twitch force transients depending on a prescribed instant of activation. Explicit prescription of activation times is not implemented in CARPentry, rather the instant of activation is derived from the upstroke of the action potential of the cell model. For instance
Calcium-based weak coupling with biophysical active stress models
In this scenario the active stress plugin is driven by the intracellular Calcium trace
. As myocyte and myofilament are weakly unidirectionally coupled,
any effects due to stretch onto Calcium are ignored.
That is, enforcing a step change in length does not change intracellular Calcium
by binding more or less Calcium to the Troponin-C buffer.
That is, length and velocity dependence are accounted for, but not their feedback
on the electrophysiological state.
Calcium-based weak coupling with biophysical active stress models
In this scenario myocyte and myofilament model are strongly bidirectionally coupled, that is, enforcing a step change in length does change intracellular Calcium by binding more or less Calcium to the Troponin-C buffer.
A tutorial on how to configure single cell electromechanics is found here.
Excitation-Contraction Coupling (ECC)
At the single cell scale ECC and MEF mechanisms are steered through turning on specific plugins which account for
Essentially, there are three ways of how models of cellular dynamics can be coupled with active stress models:
- The easiest
Mechano-electric Feedback (MEF)
TBA