Neurite outgrowth in response to exogenous cues. A, neurite outgrowth of control and TrioNKO cerebellar neurons cultured for 2.5 days in vitro with control buffer and the buffer with Netrin-1. B, quantification of mean axon length of cerebellar granule cells 2.5 days after plating with control buffer, glutamate, Netrin-1, nerve growth factor, and Semaphorin 6A/Fc; *, p < 0.05; **, p < 0.01. Scale bar in A, 20 μm.