How are neurons wired to form functional and plastic circuits?

In September 2008, more than 400 neuroscientists gathered in Cold Spring Harbor (NY, USA) to discuss how axons in the nervous system navigate to their synaptic targets to create highly organized connections with intriguing properties of plasticity and adaptability. Traditionally, this meeting not only features research on axon guidance, but also includes a consideration of additional processes in neural development that are relevant to circuit formation, including cell positioning and migration, synapse formation and plasticity, dendrite development and axon regeneration. This year was no exception. Coincidentally, many of the molecules that were initially identified as axon-guidance molecules are now also known to have a role in many of these other events. A rich diversity of work was presented from the identification of guidance cues, receptors and signal-transduction pathways to the function of these cues in pathfinding and target selection. In addition, the cell-biol\udogical mechanisms by which these cues act were discussed, as well as the transcriptional and translational mechanisms that control their action. Functional imaging of developing and adult circuits was also presented. Of course, the meeting did not solve all problems in axon guidance; however, it clearly reflected new directions in axon-guidance studies. The field is becoming a more interdisciplinary and multilevel forum that addresses a central problem of developmental neuroscience: the formation of functional neural circuits. This meeting report highlights some of the exciting advances that were presented at the meeting