Extended Data Figure 4: Large invaginations adjacent to the active zone are endocytic intermediates.

a–l, Additional representative micrographs showing shallow invaginations 50 ms after stimulation (a, e, i), deep invaginations 100 ms after stimulation (b, c, f, g, j, k) and large vesicles at the edge of active zone 300 ms after stimulation (d, h, l). m, o, Coats are usually absent on ultrafast invaginations, but can occasionally be observed (j, k, arrow). n, p, But these differ from those observed at classical clathrin coated pits (n) or vesicles (p). The coated pit (n) was not observed at the synapse but was rather at the plasma membrane of soma.