Epigenetics and the Formation of Long-Term Memory

Abstract

The most urgent problem in neurobiology is the search for the mechanisms underlying long-term memory. Gene expression has been shown to be needed for long-term memory to form. Which genes are expressed and how their expression is regulated are subject to intense investigation. The task is complicated by the multicomponent nature of the systems regulating the genome. A number of DNA-binding transcription factors involved in regulating gene expression in learning have now been identified. However, activation of these factors alone is insufficient to induce expression; modification (remodeling) of chromatin is also required. Chromatin remodeling processes are epigenetic. The most important roles in chromatin remodeling are played by the processes of phosphorylation, acetylation, and methylation of histones and methylation of DNA. Impairments to these processes lead to the inability to form long-term memory. This review addresses the role of transcription factors and chromatin modifications in the formation of long-term memory in invertebrates and vertebrates and assesses the potential for improving memory by modifying epigenetic mechanisms.