Conceptual framework for understanding how sex differences in histone modifications can coincide with similarities or differences in memory performance. (A) Sex differences in epigenetic modifications may be due in part, to sex differences in brain regions recruited (e.g., Gasbarri et al. 2007; Cahill 2011; Bellace et al. 2013; Keiser et al. 2017) and circuits activated during consolidation or retrieval of memory or in behavioral strategies engaged during learning and/or expression of memory (Rodríguez et al. 2011; Bettis and Jacobs 2013; Keeley et al. 2013; Shah et al. 2013; Gruene et al. 2015). Intact memory retrieval in both females and males may exist despite sex differences in histone modifications (e.g., Sase et al. 2019). (B) Sex differences in epigenetic modifications may facilitate sex differences in expression of genes involved in memory (see Fig. 1) which may impact sex differences in brain regions/circuits activated during retrieval, potentially influencing sex differences in memory performance. Not presented here, but important to note is also the possibility of similar histone modifications between females and males coinciding with differences in memory performance.
