Statistical analysis
Statistical analysis of immunohistochemical and fibre photometry data was conducted using GraphPad Prism (version 9.3). Data normality was assessed using the Shapiro-Wilk test and any outliers identified using Grubbs’ test were excluded. For the BL/6 experiment investigating the distribution of BA-NAc neurons responsive to SR and/or SA, data for neuronal number and density were analyzed using two-way repeated measures ANOVAs, with a between-subjects factor of stimulus group (No S, SR, SA) and within-subjects factor of bregma level (from -1.0 to -2.6 mm). Significant interaction or main effects were analyzed using Tukey’s or Sidak’s multiple comparison post hoc tests. For the TRAPing experiment investigating intermediate-BA-NAc neuron responsiveness to SR and/or SA, data for neuronal number were analyzed using two-way repeated measures ANOVA, with a between-subjects factor of stimulus group (No S, SR-SA, SA-SR, SR-SR, SA-SA) and within-subjects factor of activity marker (tdTom, c-Fos). Significant interaction or main effects were analyzed using Tukey’s or Sidak’s multiple comparison post hoctests. For the fibre photometry experiment, the z-scored Ca2+ (or EGFP) activity data in peri-event histograms were collapsed into one mean value for baseline and one mean value per 1 s time bin for the 10 s of post-event data, and a two-way repeated measures ANOVA was conducted with within-subjects factors of phase (distal, proximal) and time (from 0 to 10 s). The significant phase x time interaction effect was analyzed between phases usind Sidak’s multiple comparison and, within phase, post-event Ca2+activity at each 1 s time bin was compared with baseline using Dunnett’s multiple comparison test. Data are presented as mean ± SEM. Statistical significance was set at p ≤ 0.05.
Results