Figure 4.

3D reconstructions of representative synaptic complexes. A, A labeled bouton (red), sampled from animal 12901, forming a synapse with a dendritic shaft (orange) and a dendritic spine (yellow). Four unlabeled boutons (blue, pink, turquoise, and purple) are making additional converging synaptic contacts with the same shaft. Synaptic clefts and specializations are color coded as light green. The reconstructions are based on serial sections of the synaptic complex demonstrated in Figure 2F. B, A labeled MSB (red), sampled from animal 13976, forming a synapse with four separate dendritic spines (yellow, turquoise, blue, and purple). The synapses made with the purple and blue spines are perforated. Synaptic clefts and specializations are color coded as light green.