COMPETING PATTERNS OF SIGNALING ACTIVITY IN DICTYOSTELIUM-DISCOIDEUM

Quantitative experiments are described on spatiotemporal patterns of c oherent chemical signaling activity in populations of Dictyostelium di scoideum amoebae. We observe competition between spontaneously firing centers and rotating spiral waves that depends strongly on the overall cell density. concentric waves. whereas at high densities the firing centers seen at early times nucleate and are apparently entrained by s piral waves whose cores ultimately serve as aggregation centers. Possi ble mechanisms for these observations are discussed.