Downstream connector segmentation to a CryoVesNet-segmented cultured mouse neuron synapse. (A) Slice through a tomogram. (B) Threshold-based segmentation of plasma membrane (light blue), mitochondria (dark blue), endosomes (green), microtubules (dark magenta). (C) SVs (orange) and connectors (black) segmented with CryoVesNet and Pyto, respectively. (D) Combination of B and C. Scale bar, 100 nm.