A mammalian Green Fluorescent Protein (GFP) Reconstruction Across Synaptic Partners (mGRASP) method and system is provided by optimizing synaptic transmelectron microscopicbrane carriers for mammalian synapses. The method and system in one form integrates molecular and cellular approaches with a novel computational strategy to reliably reconstruct neurons in 3D. The method and system allows mGRASP to be applied to both long-range and local microcircuits, analysis of synaptic distribution at the level of single neurons and dendritic compartments within neural cells.