Reconsolidation and extinction: Using epigenetic signatures to challenge conventional wisdom

• We review the role of key epigenetic mechanisms in reconsolidation and extinction of learned fear.
• We discuss the potential of epigenetic mechanisms to persistently alter behavioral responses.
• We discuss how epigenetic processes may challenge our definition of extinction/reconsolidation.

Epigenetic mechanisms have the potential to give rise to lasting changes in cell function that ultimately can affect behavior persistently. This concept is especially interesting with respect to fear reconsolidation and fear memory extinction. These two behavioral approaches are used in the laboratory to investigate how fear memory can be attenuated, which becomes important when searching for therapeutic intervention to treat anxiety disorders and post-traumatic stress disorder. Here we review the role of several key epigenetic mechanisms in reconsolidation and extinction of learned fear and their potential to persistently alter behavioral responses to conditioned cues. We also briefly discuss how epigenetic mechanisms may establish persistent behaviors that challenge our definitions of extinction and reconsolidation.