Neuron Review Decoding the Epigenetic Language of Neuronal Plasticity

Neurons are submitted to an exceptional variety of stimuli and are able to convert these into high-order func-tions, such as storing memories, controlling behavior, and governing consciousness. These unique proper-ties are based on the highly flexible nature of neurons, a characteristic that can be regulated by the complex molecular machinery that controls gene expression. Epigenetic control, which largely involves events of chromatin remodeling, appears to be one way in which transcriptional regulation of gene expression can be modified in neurons. This review will focus on how epigenetic control in the mature nervous system may guide dynamic plasticity processes and long-lasting cellular neuronal responses. We outline the molec-ular pathways underlying chromatin transitions, propose the presence of an ‘‘epigenetic indexing code,’ ’ and discuss how central findings accumulating at an exponential pace in the field of epigenetics are conceptually changing our perspective of adult brain function. The ability to store information over long periods of time lies at the heart of cellular identity. This cellular ‘‘memory’ ’ is encoded in the specific pattern of expressed genes and allows a cell to ensure that it ‘‘remembers’ ’ who it is and how it should move along elaborate pathways during cellular development an