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. 2010 Nov 2;8(11):e1000527. doi: 10.1371/journal.pbio.1000527

Figure 4. Ultrastructural relationships between microglia and synapses during altered visual experience.

Figure 4

(A and B) EM image from a DA animal showing multiple cellular inclusions (in) in an IBA1-positive microglial perikaryon (m+). (B) shows a magnified view of the boxed region in (A). One inclusion resembles a dendritic spine (“s”) receiving a synapse from an axon terminal (“t”), while the other inclusion contains an accumulation of cellular membranes (“cm”). a, perisynaptic astrocyte; N, nucleus; s, dendritic spine; t, axon terminal. Scale bars = 250 nm. (C and D) EM images taken in DA (C) and DA+light (D) animals displaying two “spindly” microglial processes making multiple contacts with synapse-associated elements, including synaptic clefts (white arrowheads). Note that the process in (C) is surrounded by extended extracellular space (asterisks) in contrast with the process in (D). Color scheme as in Figure 1. d, dendrite. Scale bars = 250 nm. (E) Change in the total number of cellular inclusions for 50 IBA1-positive microglial processes during DA and DA+light (mean ± SEM). (F and G) Change in microglial process area and microglia-associated extracellular space area for 50 IBA1-positive microglial processes during DA and DA+light (mean ± SEM). (H and I) Total number of contacts and average perimeter of contact between 50 IBA1-positive microglial processes and every synapse-associated element (mean ± SEM). *, p<0.05; **, p<0.01; ***, p<0.001. Black asterisks refer to comparisons with control animals and grey asterisks to comparisons with DA animals. See also Figures S9 and S10 and Tables S1 and S2.