Fig 1: Specific gene transduction in CA2 pyramidal cells by AAV dual infection. (a) AAV2/PHP.eB-SynTetOff-FLEX-[hChR2-mCherry] vector. (b) Dual injection into the CA2 area (AAV2/1-SYN-iCre-2A-EGFP or AAV2/1-SYN-iCre) and the LV (AAV2/PHP.eB-SynTetOff-FLEX-[hChR2-mCherry]). (c) Expression of hChR2-mCherry and GFP in Nissl-stained hippocampus. Scale bars, 200 μm (top) and 100 μm (bottom). (d) Intracellular labeling of a hChR2-mCherry-expressing cell after targeted patch-clamp recording. Slice were immunostained for RGS14 and stained with a fluorescent Nissl. Top shows a merged view of biocytin (green), fluorescent Nissl (Blue), and hChR2-mCherry (Red). Bottom shows an enlarged image of the rectangle in the top. Arrowhead indicates the recorded neuron. Scale bars, 50 μm (top) and 20 μm (bottom). (e) (Top) Representative trace of the membrane responses to photostimulation at a duration of 100 ms. Scale bars, 100 ms (horizontal) and 20 mV (vertical). (Middle) Raster plot of spikes stimulated by blue-light illumination. (Inset) Membrane potential evoked by current injection into the same neuron. Scale bars, 100 ms (horizontal), 20 mV, and 400 pA (vertical). (Bottom) Firing rate was increased during blue-light illumination in recorded 4 cells from 3 mice.