Figure 1. Expression of transgenes using AAV vectors does not lead to lasting astrocytic reactivity or microglial activation. A, Fluorescence immunolabeling of nuclei (DAPI, blue), astrocytic GFAP (green), and Lck-GCaMP6s (gray) in visual cortex. Right, AAV-injected cortex. Left, Noninjected cortex from same animal. B, Same images as in A but with GFAP only, more clearly displaying similarly sparse labeling in AAV-injected and noninjected cortices. C, Fluorescence immunolabeling of nuclei (DAPI, blue), astrocytic GFAP (green), and Lck-GCaMP6s (gray) in visual cortex near the center of AAV injection and needle penetration. Right, GFAP only. D, Fluorescence immunolabeling of nuclei (DAPI, blue), microglia (Iba1, red), and Lck-GCaMP6s (gray) in visual cortex. Right, AAV-injected cortex. Left, Noninjected cortex from same animal. E, Same images as in D but with Iba1 only, more clearly displaying similar gross microglial morphology in AAV-injected and noninjected cortices. Scale bars: A, B, 500 μm; C, 250 μm; D, E, 50 μm.