Fig. 3: Synaptic strength is enhanced in prefrontal social engram cells.

A Experimental design for social-associated ensemble labeling. Doxycycline was taken off 24 hours before the social test on Day 5 and placed back 24 h after it. B Electrophysiological experimental design for recording labeled neurons in layers V/VI and adjacent unlabeled neurons of the mPFC on Day 12, with a concentric bipolar electrode positioned in layers II/III. C Representative traces (left) and statistical graph (right) of Input-output curves of evoked AMPA-receptor-mediated synaptic responses recorded from RAM⁺ and nearby RAM^- pyramidal neurons in the mPFC (two-way ANOVA, Interaction: F_{(5, 122)} = 2.064, p = 0.074; Stimulus intensity: F_{(5, 122)} = 22.68, p < 0.0001; RAM^- vs. RAM⁺: F_{(1, 122)} = 19.38, p < 0.0001; n = 13 and 11 neurons recorded from 4 mice). D Representative traces (left) and statistical graph (right) of PPR recorded from RAM⁺ and nearby RAM^- pyramidal neurons in the mPFC (two-way ANOVA, Interaction: F_{(4, 89)} = 0.824,p = 0.513; Interval: F_{(4, 89)} = 6.596, p = 0.0001; RAM^- vs. RAM⁺: F_{(1, 89)} = 0.786, p = 0.378; n = 11 and 9 neurons recorded from 4 mice). E High-frequency stimulation fails to induce NMDAR-dependent LTP in the RAM⁺ pyramidal neurons in the mPFC. Top: Representative traces of averaged EPSCs recorded 5 minutes before (dark traces) and 25 min after (light traces) LTP induction. Below: Changes in EPSC amplitude induced by 100 Hz stimulation and quantification of EPSCs 25 min after stimulation compared to the respective values before stimulation in RAM^-, RAM^- +AP5 and RAM⁺ pyramidal neurons (one-way ANOVA, Between columns: F_{(2, 21)} = 19.96, p < 0.0001; RAM^- vs. RAM^- +AP5: p < 0.0001; RAM^- vs. RAM⁺: p = 0.0001; n, number of neurons recorded from 6 mice per group).All data were mean ± SEM. *p < 0.05, **p < 0.01, ***p < 0.001.