A gene called “Arc” could be the gateway to immortality—or at least limitless brain plasticity. Researchers from Japan and the US restored plasticity in the visual cortex of middle-aged mice brains by inducing overexpression of the gene. The end result was a more youthful brain, and though no one wants to relive high school, having the plasticity we had back then with the experience we have in middle age could be an unbeatable combination.
We know now that the brain changes throughout our lives, but that we are less able to learn new things and adapt to new situations as we lose neuroplasticity—literally the ability to form novel connections in the brain. This study suggests we might be able to restore this ability to last throughout our lives.
The researchers started with the knowledge that our brains undergo critical periods of plasticity that promote brain development during childhood. They then asked the questions: how are these plasticity windows regulated, and can we stretch them out? The team then observed that mice without the Arc gene were unable to adapt to new experiences, and the answer suggested itself.
Specifically, in mice without the Arc gene, visual cortex neurons did not change their electrophysiological activity in response to a loss of sight. In normal mice, there was a demonstrative adaptation easily observed. The team decided in this latest study to determine whether Arc helps open that plasticity window, and if it does, whether it can be persuaded to leave the gate open.
Restoring youthful brain function
The team first monitored middle-aged mice with high Arc gene expression throughout their lives to see what plasticity in the visual cortex looked like. They saw that the visual cortex adapted just as it did in younger mice, signaling that this abundance of Arc might in fact be prolonging the plasticity window. Once they delivered Arc via virus to Arc-deficient middle-aged mice, they saw the same adaptation.
They were also able to open new plasticity windows even in mice whose windows had previously closed altogether. The team doesn't yet know whether this works outside the visual cortex, which suggests an important next research step. The researchers also plan to explore boosting plasticity to repair stroke and traumatic brain injury damage, and preventing age-related cognitive decline.