Stochastic fluctuations of voltage-gated ion channels generate current and voltage noise in neuronal membranes. This noise may be a critical determinant of the efficacy of information processing within neural systems. Using Monte-Carlo simulations, we carry out a systematic investigation of the relationship between channel kinetics and the resulting membrane voltage noise using a stochastic Mar...

It is well known that excitable media can sustain “fast” stable traveling pulses of excitation. In models for which analysis is tractable, the fast pulse solution is known to appear through a saddlenode bifurcation accompanied by a “slow” unstable traveling pulse. Furthermore, the uniform rest state is also a stable solution. It is generally assumed that the boundary between the basins of attra...

Action potential or Spikes: electrical pulses of an amplitude of about 100mV that travel along nerve fibers. Field potential an electrical signal recorded extracellularly which arises from the synchronized activity of many cells. Hippocampus one of the most studied area of the mammalian nervous system which is part of the limbic system and is involved in learning and memory. Neuron the main exc...

Although the exact details are disputed, it is well established that propagating waves of increased intracellular free Ca2+ concentration arise from a positive feedback or autocatalytic mechanism whereby Ca2+ stimulates its own release. Most previous modeling of the propagation of Ca2+ waves has assumed that the sites of autocatalytic Ca2+ release, the activation sites, are homogeneously distri...

Voting rules allow multiple agents to aggregate their preferences in order to reach joint decisions. Perhaps one of the most important desirable properties in this context is Condorcet-consistency, which requires that a voting rule should return an alternative that is preferred to any other alternative by some majority of voters. Another desirable property is participation, which requires that ...

This paper discusses possible routes to moving the web from a collection of human readable pieces of information connecting humans, to a web that connects computing devices based on machine-processable semantics of data and distributed computing. The current shortcomings of web service technology are analyzed and a new paradigm for fully enabled semantic web services is proposed which is called...

A system of ODE’s is used to attempt an approximation of the dynamics of two delayed coupled FitzHugh-Nagumo excitable units, described by delay-differential equations. It is shown that the codimension 2 generalized Hopf bifurcation acts as the organizing center for the dynamics of ODE’s for small time-lags. Furthermore, this is used to explain important qualitative properties of the exact dyna...

The three-color Greenberg{Hastings model (GHM) is a simple cellular automaton model for an excitable medium. Each site on the lattice Z 2 is initially assigned one of the states 0, 1 or 2. At each tick of a discrete{time clock, the connguration changes according to the following synchronous rule: changes 1 ! 2 and 2 ! 0 are automatic, while an x in state 0 may either stay in the same state or c...

This article focuses on the pattern language PLML. Some enhancements and corrections to it are proposed to make use of PLML in pattern catalogs. Additionally, a textual domain specific language as human-readable variant of PLML is proposed. Supporting editors, textual and graphical, which were developed using model-based techniques are presented.

Magnetic drug targeting (MDT) therapy is usually controlled through the magnetic field produced by a permanent magnet; the solution proposed and assessed here considers a planar spiral coil (PSC) or a system of such coils, as an equally effective magnetic field source. The PSC may be designed to provide proper configurations of the magnetic field gradients, required for the generation of high m...