Statistical analysis
Three-way ANOVA with repeated measures was used to test the evolution over sessions or days. Sessions or days were used as within-subject factors and genotype (Plcb1+/- or WT) and drug (cocaine or saline) were used as between-subjects factors. Post-hoc analyses (Newman-Keuls) were performed when required. Comparisons between two groups were analyzed by Student t -test or U -Mann-Whitney depending on the distribution defined by the Kolmogorov-Smirnov normality test and the sample size. The chi-square analyses were performed to compare the percentage of mice that acquired operant learning criteria in the different experimental groups. Results are expressed as mean ± SEM or individual values with the median and the interquartile range specified in the figure legend. Differences were considered significant at P <0.05. The sample size was calculated based on power analysis. The statistical analyses were performed using the Statistical Package for Social Science tool SPSS®25.0 (SPSS Inc, Chicago, USA).
See supplementary information for more details of genotyping of transgenic mice, drugs, behavioral tests of phenotype characterization, operant conditioning maintained by cocaine, RNA extraction and sequencing.