Supplementary Figure 7: ChR2-assisted circuit mapping of mossy-fiber inputs to CA3 pyramidal cell types.
From: A novel pyramidal cell type promotes sharp-wave synchronization in the hippocampus
a) Expression pattern of Rbp4cre mice crossed to the Ai9 reporter line illustrating dense expression in the dentate gyrus, specifically in mature granule cells. b) Validation that optical activation drives spiking in dentate granule cells when crossed with the Ai32 line (ChR2-YFP). c) Schematic of experimental design for ChR2-assisted circuit mapping of mossy fiber inputs to CA3 pyramidal cell-types. d) Two representative examples of superficial-layer (close to stratum lucidum, green band) that exhibited regular spiking phenotypes (n = 2 cells). e) Two representative examples of deep-layer (close to stratum oriens) that exhibited bursting phenotypes (n = 2 cells). f) Expression pattern of Pomc1cre mice crossed to the Ai9 reporter line illustrating sparse expression in the dentate gyrus, specifically in immature granule cells (n = 10 animals). g) Representative traces from a regular spiking cell (top) and bursting cell (bottom) illustrating synaptic responses only observed in regular spiking cells when elicited by optical activation of mossy fibers in Pomccre mice. For a total of 11 bursting neurons recorded, none exhibited synaptic responses, while 4 of 9 regular spiking cells displayed typical mossy-fiber synaptic responses.
