Different morphologies of human synaptoneurosomes fixed over glass slides. Intact, bipartite synapses appear as snowman-like or elongated/protruded structures under the brightfield, with VGluT1 (presynaptic marker) and MAP2 (postsynaptic marker) immunofluorescence on opposing sides. Isolated hemi-synapses and clusters of synapses are more abundant than bipartite structures. The ratio of bipartite synapse/hemi-synapse/clustered synapse is approximately 5%/50%/45%. Organelles negative for synaptic markers account for about half of the brightfield objects, and these were excluded from our analysis of tau immunofluorescence.