Figure 2. Detection of experience-associated FOS levels with nuclei staining.

(a) Representative FACS plots showing the gating strategy for the identification of PROX1+NEUN+ DG nuclei in the hippocampus of wild-type mice, n=3. Staining in cortex is shown as control. (b) Representative FACS plots showing FOS protein expression in PROX1+Hoechst+single-nuclei isolated from the hippocampus of PTZ-treated and HC mice, n=4. FOS protein expression was only observed in PTZ-treated animals. (c) Confocal images of FOS protein expression in the DG of a mouse either from home cage (HC) (top) or after recovery from a brief exposure to a novel environment (NE; middle and bottom). One hour after a 15-min exploration period in the NE, FOS was sparsely induced in the granule cell layer (middle). Four hours after NE FOS returned to lower levels similar to HC (bottom). Scale bar, 100 μm. (d) Representative FACS plots showing FOS protein expression in PROX1+Hoechst+single-nuclei isolated from the hippocampi of animals from HC, 1 h,or 4 h after a 15-min exposure to an NE. (e) Percentage of PROX1+FOS^high in the hippocampi of animals from HC 0.5 h, 1 h, 1.5 h, 2 h or 4 h after a 15-min exposure to an NE, error bars represent standard deviation from the mean (N=4 per time-point).