We present an exact method of greatly speeding up belief propagation (BP) for a wide variety of potential functions in pairwise MRFs and other graphical models. Specifically, our technique applies whenever the pairwise potentials have been truncated to a constant value for most pairs of states, as is commonly done in MRF models with robust potentials (such as stereo) that impose an upper bound ...

RATIONALE Human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) offer a powerful in vitro tool to investigate disease mechanisms and to perform patient-specific drug screening. To date, electrophysiological analysis of iPSC-CMs has been limited to single-cell recordings or low-resolution microelectrode array mapping of small cardiomyocyte aggregates. New methods of generating an...

We derive a homogenized description of the electrical communication along a single strand of myocytes in the presence of gap-junctional and electric-field coupling. In the model, cells are electrically coupled through narrow clefts that are resistively connected to extracellular space. Cells are also coupled directly through gap junctions. We perform numerical simulations of this full model and...

Rapid action potential propagation in myelinated axons requires Na⁺ channel clustering at nodes of Ranvier. However, the mechanism of clustering at CNS nodes remains poorly understood. Here, we show that the assembly of nodes of Ranvier in the CNS involves three mechanisms: a glia-derived extracellular matrix (ECM) complex containing proteoglycans and adhesion molecules that cluster NF186, para...

A novel approach is proposed in order to reduce the number of sweeps (trials) required for the efficient extraction of the brain evoked potentials (EPs). This approach is developed by combining both the Wiener filtering and the subspace methods. First, the signal subspace is estimated by applying the singularvalue decomposition (SVD) to an enhanced version of the raw data obtained by Wiener fil...

The effects of the discrete cellular structure on propagation of electrical excitation in cardiac muscle were studied in a one-dimensional fiber model containing a periodic intercalated disk structure. Globally, the macroscopic velocity of propagation follows the behavior associated with propagation in a continuous tissue (except for high values of disk resistance). In addition, the computed sp...

Study of neurons plays a key role in the fields of basic and medical research aiming at the development of electrically active implants. The Fitzhugh-Nagumo equations are used to model and simulate the spike generation and propagation in a squid giant axon using Comsol Multiphysics® 3.5a Software. It is shown that the Fitzhugh-Nagumo equations allow for a geometrical explanation of important bi...

Action potentials in central neurons are initiated near the axon initial segment, propagate into the axon, and finally invade the presynaptic terminals, where they trigger transmitter release. Voltage-gated Na(+) channels are key determinants of excitability, but Na(+) channel density and properties in axons and presynaptic terminals of cortical neurons have not been examined yet. In hippocampa...