UAS regulatory sequences drive expression of a protein in which a signal peptide and the spGFP1-10 split GFP fluorescent protein fragment are fused to the N-terminal end of a portion of Mmus\Icam5 (806 amino acid residues) that includes a transmembrane domain and extracellular sequence. The Mmus\Icam5 sequence results in the protein being targeted to dendrites. This construct is designed for use in the activity-independent t-GRASP (targeted GFP Reconstitution Across Synaptic Partners) assay, in which complementary split fluorescent protein fragments expressed on the extracellular surface of different neurons (the two components are targeted to pre-synaptic terminals and dendrites respectively) can reconstitute a functional fluorescent protein at points of synaptic contact between the neurons. Thus t-GRASP can be used to assess neural connectivity.