Fig. 3

PNNs and their perforating synapses visualized using confocal microscopy. Confocal microscopy of WFA-labeled neurons shows characteristic facet-like morphology of PNNs. PNN facets form synaptic pockets (arrowheads), within which presynaptic terminals contact the neuronal surface (dash line) and establish synapses. GABAergic (A) and glutamatergic (B) terminals are shown by vesicular GABA (VGAT, red) and glutamate (VGLUT1) transporter labeling, correspondingly. Arrowheads and dash lines indicate putative synaptic pockets and neuronal surfaces, correspondingly. Scale bars, 2 µm. ECS, extracellular space