Every day, our brains transform quick impressions, flashes of inspiration, and painful moments into enduring memories that underpin our sense of self and inform how we navigate the world. But how does the brain decide which bits of information are worth keeping—and how long to hold on?

Now, new research demonstrates that long-term memory is formed by a cascade of molecular “timers” unfolding across brain regions. With a virtual reality-based behavioral model in mice, the scientists discovered that long-term memory is orchestrated by key regulators that either promote memories into progressively more lasting forms or demote them until they are forgotten.

The findings, published in Nature, highlight the roles of multiple brain regions in gradually reorganizing memories into more enduring forms, with gates along the way to assess salience and promote durability.