Contents

09 March 2001
Vol 291, Issue 5510

About The Cover

Cover image expansion

COVER Two neuronal axons on a two-dimensional substrate, visualized by fluorescent staining of filamentous actin. One axon originates from a cell body beyond the top right and extends diagonally downward. The other, originating from a cell body beyond the bottom, is turning upward. The expanded tip of each axon, the growth cone, extends protrusions, filopodia, in search of proteins such as netrin and Slit, which guide axons to their destinations in the developing nervous system. (Image width, 120 mm; bottom right, nonneuronal cell.) See page 1928 [Image: E. Stein and M. Tessier-Lavigne]