The visual representation is incredible detailed and unveils the enormous density of proteins in the synaptic bouton. The scientists used an array of equipment and techniques, including Western blot, mass spectrometry, electron microscopy, and super-resolution fluorescence microscopy.
Writing in National Geographic, Virginia Hughes explains:
The video shows the synaptic bouton…The glowing red “active zone” at the bottom is where the neurotransmitters get dumped into the cleft. Toward the end of the video you can see a close-up of a vesicle releasing its contents and then being recycled by the cell.
The model shows some 300,000 individual proteins, and remember — they’re all hanging out at a single synapse! The image below shows a cross-section of the bouton; each color corresponds to a different kind of protein. The active zone is again the glowing red part at the bottom.
Watch a fascinating video with some more details here: