Fig. 3: NA, astrocyte cAMP and Ca²⁺ signals before, during and after fear experiences.

a, AAV injection of GRAB_NE2h with optical fibre above LA/B to monitor bulk NA response (representative image from 6 mice; scale bar, 200 µm). b, ΔF/F traces showing NA signals in home cage (HC) and CtxA on fear conditioning (FC) day. NA signal increased with CtxA exposure and foot shocks, and showed larger, longer responses during recall (FR). Right, summary plots (n = 5–6 mice). AUC, area under the curve. c, Top, AAV injection of astrocyte-selective cAMPinG1 and RCaMP3 with optical fibre above LA/B to monitor astrocyte cAMP and Ca²⁺. Bottom, co-expression of cAMPinG1 and RCaMP3 in LA/B astrocytes (representative image from 8 mice; scale bars: 200 µm (main image), 20 µm (magnified views, bottom)). d, Astrocyte cAMP signals increased with context exposure and shocks, and during FR they increased gradually from HC baseline and were further enhanced in CtxA. Propranolol (10 mg kg⁻¹, β-receptor antagonist) abolished these effects. Right, summary plot (n = 8 mice). e, Astrocyte Ca²⁺ signals also increased with context exposure and shocks. During FR, Ca²⁺ amplitude was reduced but event frequency was significantly higher. Right, summary plots (n = 7 mice). Wilcoxon signed-rank test. Data are mean ± s.e.m; in some cases, error bars are smaller than symbols. Sample sizes and number of replicates in Supplementary Table 1.