The spGFP1-10 split GFP fluorescent protein fragment present in nSyblexAop.spGFP1-10 has been replaced by a YFP version (spYFP1-10). This construct is designed for use in a GRASP (GFP Reconstitution Across Synaptic Partners) assay, in which complementary split fluorescent protein fragments expressed on the extracellular membrane of different neurons can reconstitute a functional fluorescent protein at points of contact between the neurons.