astrocyte.

OSCILLATORY INSTABILITY AND SPONTANEOUS SUBTHRESHOLD OSCILLATIONS IN A NETWORK OF DIFFUSIVELY COUPLED CALCIUM OSCILLATORS

The paper is devoted to the investigation of the dynamics of a network of interacting astrocytes. The astrocytes represent brain glial cells capable to generate chemical activity signals (calcium pulses). Similarly to nerve cells (neurons) the astrocytes form networksof interacting units coupled by means of gap junctions. The junctions represent special protein channels providing the diffusion of chemically active species between neighboring cells.

CALCIUM OSCILLATIONS IN ASTROCYTES Part 2 Dynamics of interacting calcium oscillators

We investigated bifurcation mechanisms of oscillatory dynamics of interacting chemically excitable cells (astrocytes). In model of three interacting astrocytes we studied bifurcation transitions leading to generation of calcium oscillations induced by the intercellular diffusion. We analyzed basic mechanisms of limit cycle instabilities and destructions, typical transitions to chaotic oscillations and basic properties of intercellular synchronization.

CALCIUM OSCILLATIONS IN ASTROCYTES Part 1 Astrocyte as generator of calcium oscillations

Bifurcation mechanisms of oscillatory dynamics in a biophysical model of chemically excitable brain cells (astrocytes) were analyzed. In contrast to neuronal oscillators widely studied in nonlinear dynamics the astrocytes do not possess electrical excitability but capable to generate chemical oscillations which modulate neuronal signaling. Astrocyte dynamics is described by third-order system of ordinary differential equations derived from biophysical kinetics.