DSCAM is a single-transmembrane domain cell adhesion molecule with immunoglobulin and fibronectin domains that is expressed strongly in brain [169, 174] and in hippocampus in ways that are required for appropriate neuronal connections to form in memory-associated circuits in model organisms [162, 163]. Different dendritic processes of the same neuron do not often cross each other; this self-avoidance mechanism depends on expression of a large array of tightly-regulated DSCAM isoforms [175, 176]. Simplifying this repertoire substantially disrupts appropriate formation of neuronal networks in vivo [177]. Indeed, flies with altered DSCAM expression display altered memories for both rewarded and punished behaviors [163].
