Microglia and Synapse: Interactions in Health and Neurodegeneration
Figure 2
Three-dimensional reconstruction of microglial relationships with multiple synaptic elements at multiple synapses in physiological conditions. (a) Partial reconstruction of a microglial proximal process (P), cut in transverse, and a distal protrusion (D), cut longitudinally, in adolescent mouse visual cortex. The purple element indicates a phagocytic inclusion. The process and protrusion simultaneously contact multiple axonal terminals (in blue), dendritic spines (in red), and perisynaptic astrocytic processes (in green) and are distinctively surrounded by extracellular space pockets (arrows) of various sizes and shapes (in white). (b) Additional view showing only microglia, dendritic spines, and extracellular space. (c) and (d) Insets illustrating the three-dimensional relationships between the distal protrusion, one axonal terminal (t1), two dendritic spines (s1 and s2; postsynaptic density in dark red), and a pocket of extracellular space (in white), which are partially reconstructed. For clarity, an astrocytic process was removed from the scene. Scale bar: 250 nm. Reproduced from Tremblay et al. [30].
