title: The emergence of wave emitting centres in an excitable medium.
abstract: The response of an excitable biological medium to a double local stimulus is considered within the context of a mathematical model for a layer of starving cells of Dictyostelium discoideum, with both spatially one- and two-dimensional (1D and 2D) system being investigated. In contrast to the response usually seen in excitable media, whereby each superthreshold stimulus delivered to the relaxed medium results in the initiation of just one travelling wave, a source emitting a sequence of waves can develop in the present excitable medium after the second stimulus. In a 1D system, only transient wave sources forming a limited number of waves are found. In 2D systems, a permanent wave sources consisting in a pair of spirals are observed as well as the transient wave sources forming circular wave patterns. The general features of the medium dynamics that underlie the observed responses to the double stimulus are discussed.
authors.affiliation: Center for Nonlinear Dynamics of Chemical and Biological Systems, Prague Institute of Chemical Technology, Technicka 5, 16628 Prague 6, Czech Republic. tomas.godula@vscht.cz
authors.forename: Tomas
authors.initials: T
authors.lastname: Godula
authors.forename: Hana
authors.initials: H
authors.lastname: Sevcikova
authors.forename: John H
authors.initials: JH
authors.lastname: Merkin
mesh_terms: D000818:Animals; D001683:Biological Clocks / Q000502:physiology; D002449:Cell Aggregation / Q000502:physiology; D002630:Chemotactic Factors / Q000502:physiology; D002633:Chemotaxis / Q000502:physiology; D000242:Cyclic AMP / Q000502:physiology*; D004023:Dictyostelium / Q000378:metabolism / Q000502:physiology*; D008954:Models, Biological
chemical_list: D002630:Chemotactic Factors; D000242:Cyclic AMP