We have studied the human brain for millennia, dating all the way back to the ancient Egyptians, yet we still understand little about how our most vital organ functions or how the cellular networks that operate our brain produce complex behaviors and memory storage. We know our brains take input from both genetic predispositions as well as from environmental cues—like upbringing and our unique experiences. We also know that our brains are highly flexible and responsive to our environments. Neither tells the complete story and scientists remained stumped as to how our brains ‘put it all together.’ In recent years some neurologists have proposed epigenetic modifications like methylation and histone modifications as the process that hard writes our experiences into our neurons. A major study revealed that rats who were licked more as pups were less anxious and dealt with stress better as adults—an activity that researchers linked to epigenetic modifications on a gene involved with stress hormones. Does this study implicate epigenetics as the bridge between nature and nurture in determining our behavior? Or is it are our genes and other factors that are in control? Is it epigenetics that underlies how we maintain this plasticity?