Phagocytosis of presynaptic elements by microglia in cross-modal plasticity. One of the serial electron microscopic images (a1, a2) and their three-dimensional (3D) reconstruction at low (b) and high (c) magnification show one of the microglial processes (blue) containing engulfed or phagocytosed presynaptic elements (red). The serial electron microscopic images at higher magnification (d) demonstrate phagosome with synaptic vesicles (arrowheads) in the microglial process (d insets, arrowheads). The marked areas (a, b) are magnified (c, d), and the phagosome is magnified in the insets (d3, d4). The nucleus of the microglia is labeled in the electron microscopic image and 3D reconstruction (green). Scale bars, 2 m (a), 3 m (b), 1 m (c), and 500 nm (d). Data shown as mean ± SD.
