In tests on rats, researchers Courtney Miller and David Sweatt of the University of Alabama at Birmingham concluded that a process called DNA methylation plays a role in the creation of memories.
During DNA methylation, molecules called methyl groups attach to genes and switch them off. On the other hand, a lack of methyl groups means that genes remain activated. Methylation is used by cells during embryonic development to deactivate certain genes so that cells can specialize as they form into different types of cells.
The Birmingham study found that methylation was necessary for rats to form memories and that the level of methylation directly controlled the activity of genes that either suppress or promote memory function.
In this study, the researchers focused on a memory-promoting gene called reelin and a memory-suppressing gene called protein phosphate 1.
"To our knowledge, this study is the first to present evidence that DNA methylation, once thought to be a static process after cellular differentiation, is not only dynamically regulated in the adult nervous system but also plays an integral role in memory formation," the study authors wrote in the March 15 issue of Neuron.The finding could help improve understanding of some brain disorders, including schizophrenia and autism, the researchers added.