26 January 1990
Vol 247, Issue 4941

About The Cover

A wave of increased cytosolic calcium concentration propagates from cell to cell through a confluent culture of hippocampal astrocytes. The wave, induced by glutamate and measured with fluo-3, is evident from the spatial progression of color overlay areas (in a spectral sequence from violet to red). Each color indicates an area of calcium elevation at one of seven successive 4-second intervals. See p. 474. [Digital fluorescence micrograph courtesy of Ann H. Cornell-Bell, Steven M. Finkbeiner, Mark S. Cooper, and Stephen J. Smith]