EnVivo Pharmaceuticals, a drug company based in Watertown, MA, is developing histone deacetylase (HDAC) inhibitors (to enable gene expression) that are more potent than existing ones and can easily enter the brain; its lead HDAC inhibitor can enhance both short- and long-term memory in mice.

While scientists don’t yet know exactly how this epigenetic regulation affects memory, the theory is that certain triggers, such as exercise, visual stimulation, or drugs, unwind DNA, allowing expression of genes involved in neural plasticity. That increase in gene expression might trigger development of new neural connections and, in turn, strengthen the neural circuits that underlie memory formation.