Two systems working in concert
The brain’s neurons and the genomes within them, the hardware and the software, together orchestrate one’s response to a new situation, which can vary from person to person. The same dramatic event – a challenge at school or work, a new person in one’s social circle – might cause a great deal of stress in one person, and very little in another. We now think that the neural systems of two such people are likely tuned differently by their genomic systems, perhaps as a consequence of differentially stressful past experiences. In the living brain, unlike a computer, the software can help modify the hardware, and as new situations are encountered, the functioning of the neural hardware continues to modify the genomic software. Nature has come up with a “smart” system in which hardware and software are adaptable and interact dynamically!
This reciprocity between genes and neurons continually builds on an interwoven history that stretches all the way back to inherited individual differences in temperament, which also influence gene activity. And while an acute stress might cause genomic changes that provoke fear and anger for a few hours, chronic stress due to deprivation or violence can cause debilitating health effects because it activates genomic changes in the brain that do not dissipate. In some cases, it induces long-lasting changes to the chemical structure of DNA; these changes, referred to as epigenetic, might even be passed down from one generation to the next.
We need to learn how to better read the genomic record of changes left by experience in order to predict future outcomes. Not only would this deepen our fundamental understanding of the brain, but it would also help us understand how socioeconomic stresses “get under the skin” to negatively affect health and well-being.
Research efforts, including the exciting new federal Brain Initiative, must focus on developing new technologies – both to measure neuronal activity with greater precision and to explore how the neuronal and genomic systems communicate with each other.
Brains do more than direct our behavior. They build our experiences into a coherent perception of the world. This world will be as unique for each of us as our personal history, with the potential to be sunny, or cloudy, or filled with shadows. If we can become proficient in the code our brains run on, perhaps we can learn to give these narratives a nudge in the right direction, and flood every person’s world with light.