Binge Alcohol “Drinking-in-the-Dark” Increases Fear Memory Expression in C57BL/6 Mice
William Christopher Cho ‘22, Charlie Mangan ‘22, and Professor Hadley Bergstrom
Post traumatic stress disorder (PTSD) and alcohol use disorder (AUD) are commonly diagnosed together. However, how alcohol impacts traumatic fear memory expression is not yet completely understood. While previous studies have shown that alcohol magnifies fear memory expression (Scarlata et al., 2019), this study explored how binge alcohol consumption impacts fear memory expression across sex and development in a mouse model. Adult (postnatal day (PND) 70+) and adolescent (PND 44-47) male and female mice (C57BL/6N) underwent Pavlovian fear conditioning and cued extinction, followed by a novel 5-day social alcohol Drinking-In-the-Dark (sDID) paradigm. To test for fear expression, 4-days following sDID, the conditioned stimulus was presented again. Mice were tested for contextual renewal the following day and spontaneous recovery 20 days later. Results showed that mice that consumed alcohol displayed higher levels of freezing during both the short term extinction retention test and the remote recall test. There were no significant differences in freezing levels across age and sex. These data suggest that binge levels of alcohol consumption increase fear memory expression and that these effects are persisting. We speculate that alcohol either strengthens the original fear memory or impairs the retrieval of the extinction memory, or both. Future studies will address this question. Further, we are investigating the location of alcohol-induced neuroadaptations in the brain by utilizing immunohistochemistry (IHC) to track Arc protein expression, particularly in the infralimbic cortex (IL), the prelimbic cortex, the basolateral amygdala complex (BLA), central nucleus of the amygdala (CeA) and the Bed Nucleus of the Stria Terminalis (BNST).