Attraction vs. repulsion: The growth cone decides

Axons are guided through their environment in response to signals provided by extracellular cues. These cues are transduced into motile responses by t he tip of the growing axon, the growth cone, and can be either repulsive or attractive in nature. Recent studies have suggested that how an axon respo nds to any given signal depends on the internal state of the growth cone. T his review discusses these studies and their importance for understanding h ow nerve connections are made in the developing embryo.