Selective expression of hM3Dq DREADD in forebrain excitatory neurons. A, Shown is a schematic of experimental strategy. hM3Dq DREADD was selectively expressed in the CamKIIα-positive excitatory neurons in the forebrain. tTA: tetracycline transactivator. B, Shown is a schematic of the extent of expression. Representative confocal images showing expression of hM3Dq identified by fluorescent immune-staining of HA-tag in the CA1 (C), DG (D), and cortex (E). No HA-tag immunoreactivity was observed in the genotype-control animals (F–H). Blue: DAPI; red: HA-Tag. Scale bar = 50 μm. I, Shown is a schematic showing whole-cell patch-clamp recording from the somata of CA1 pyramidal cells. J, Bath application of CNO (1 μM) resulted in robust spiking activity of CA1 pyramidal neurons. Refer to Extended Data Fig. 1-1 for spiking activity following bath application of 20 μM CNO. R: recording electrode.