Nearly two decades of research on epigenetic mechanisms in the brain have demonstrated that epigenetic marks that were once thought to be relatively static are dynamically and reversibly regulated in the brain during memory formation. Here, we focus on new research that has further expanded the dynamic nature of chromatin in memory formation through three key mechanisms. First, we discuss the emerging role of histone variants, which undergo learning-induced turnover or exchange, a process in which one histone type replaces another in chromatin. Next, we focus on chromatin remodeling complexes, which are tightly intertwined with all aspects of chromatin regulation and as such, can reposition or evict nucleosomes to promote transcriptional induction, and mediate histone variant exchange. Finally, we discuss how differential distribution of histone marks to localized narrow genomic regions and/or broadly distributed chromatin domains impact transcriptional outcomes and memory formation. Together, these studies mark a shift toward unraveling the complexity of chromatin function in memory and offer new strategies for fine tuning transcriptional outcomes to modify longevity, specificity and strength of memories.

近二十年来对大脑中表观遗传机制的研究表明，曾经被认为是相对静态的表观遗传标记在记忆形成过程中在大脑中动态且可逆地受到调节。在这里，我们关注于新的研究，该研究通过三种关键机制进一步扩展了染色质在记忆形成中的动态特性。首先，我们讨论组蛋白变体的新兴作用，这些变体经历学习诱导的更新或交换，在此过程中，一种组蛋白类型替代了染色质中的另一种。接下来，我们专注于染色质重塑复合物，它们与染色质调控的各个方面紧密交织在一起，因此，它们可以重新定位或逐出核小体以促进转录诱导，并介导组蛋白变体交换。最后，我们讨论了组蛋白标记向局部狭窄基因组区域和/或广泛分布的染色质域的差异分布如何影响转录结果和记忆形成。总之，这些研究标志着向揭示记忆中染色质功能复杂性的转变，并提供了微调转录结果以改变记忆的寿命，特异性和强度的新策略。