Figure 11.

Diverse composition of vesicles and mitochondria (Mito) in presynaptic boutons along CA3 → CA1 axons, and their response to LTP. A, 3DEM of Schaffer collateral axons illustrating their nonparallel trajectories. B, Illustration showing that only ∼50% of the presynaptic boutons contain mitochondria (dark gray structures) and synapses (red). A and B are adapted from Shepherd and Harris (1998). C, D, A reconstructed axon from the control condition (C) and an axon 2 h after LTP (D) illustrating the obvious drop in vesicles (axon, pale blue; vesicles, green spheres; mitochondria, fuchsia; PSDs, red; adapted from Bourne et al., 2013). E, Representative vesicle composition in presynaptic boutons containing mitochondria (dark blue) from the control (blue box) and LTP (red box) conditions. F, Representative vesicle composition in presynaptic boutons lacking mitochondria. For E and F, green spheres are vesicles in the reserve pool, and dark blue spheres are docked vesicles superimposed over the red PSDs. Adapted from Smith et al. (2016).