of five extinction sessions, representing each week of training in‐between no‐training weekend days (Figure 5B). Repeated measures ANOVA showed significant time and group effects for the first two extinction bins. For EXT1 to 5, pairwise comparisons revealed that the main group effect was due to increased responding in SPDS‐prone rats vs controls (P = 0.001). The difference between SPDS‐prone and SPDS‐resilient rats did not reach levels of statistical significance (P = 0.089) indicating that the two SPDS groups did not differ significantly in terms of initial extinction rates. For EXT6 to 10, SDPS‐prone rats maintained higher responding vs both control (P = 0.001) and SDPS‐resilient (P = 0.036) groups (Table S7), confirming a delay in extinction learning that depends on SDPS vulnerability. No between‐group difference in the last training week (EXT11‐15) was observed, indicating that by the end of extinction training period, all three groups performed similarly, extinguishing their responding for an alcohol reward (Figure 5B and Figure S4). Together, extinction data indicated that SDPS led to a delay in extinction learning that was most pronounced in the SDPS‐prone group. Overall, SDPS proneness resulted in persistent responding despite alcohol unavailability, a behavioral aspect not seen in resilient animals.
