Fig. 5: FR-BAE perturbations bidirectionally regulate memory stability and precision.

a, Schematic of behavioural and RNAscope analysis. b, Fos-iβARK2⁺ astrocytes in LA/B. Inset, enlarged view of an iβARK2⁺ astrocyte (representative of 12 mice). Scale bar, 200 μm. c, Reduced freezing at second recall in iβARK2 versus sustained freezing in iβARK2mut control (iβARK2mut: n = 13; iβARK2: n = 11 mice). Wilcoxon matched-pairs signed rank test. d, RNAscope images of Igfbp2 with mCherry–iβARK2 or mCherry–iβARK2mut and violin plots showing lower Igfbp2 expression in the presence of iβARK2 (iβARK2mut: n = 23; iβARK2: n = 24 cells; 4 mice per group). Mann–Whitney test. Horizontal lines represent the median. Scale bar, 10 μm. e, FR-BAE tagging with astrocytic Adrb1 overexpression. f, RNAscope images of Adrb1 and Igfbp2 in Slc1a3⁺ astrocytes with or without Adrb1 overexpression. Graphs showing increased expression with Adrb1-OE (ctrl: 501; Adrb1-OE: 1,810 cells; 18 sections from 6 mice per group). Mann–Whitney test. Scale bar, 10 μm. g,h, Images (g) and quantification (h) showing higher FR-BAE density with Adrb1 overexpression. Mann–Whitney test. Scale bar, 200 μm. i, Memory tests under weak (one-shock) versus strong (three-shock) conditioning. j, Adrb1 overexpression has no effect on freezing behaviour under strong conditioning (ctrl: n = 5; Adrb1-OE: n = 7 mice). Wilcoxon matched-pairs signed rank test. k, Under weak conditioning, Adrb1 overexpression enhanced freezing at second recall (n = 13 mice per group). Wilcoxon matched-pairs signed rank test. l, After strong conditioning, Adrb1 overexpression caused greater freezing in CtxB versus control (ctrl: n = 13; Adrb1-OE: n = 14 mice). Mann–Whitney test. m, FR engram labelling with mCherry and c-Fos immunohistochemistry 90 min after freezing test with or without Adrb1 overexpression. n,o, FR engram neurons exhibit similar density but higher reactivation with Adrb1 overexpression (ctrl: n = 15; Adrb1-OE: n = 12 slices; 3 mice per group). Scale bar, 50 μm. Mann–Whitney test. Data are mean ± s.e.m. Sample sizes and replicates in Supplementary Table 1.