Brain Discovery May Be a Breakthrough on Memories

Brain researchers appear to have figured out precisely how our brains store a particular memory as either good or bad—and the discovery could have implications for the treatment of everything from depression to PTSD. Researchers at the Salk Institute for Biological Studies in California say it all comes down to a brain molecule called neurotensin, reports Quanta. When our brain logs an experience, it also assigns to it what researchers call a positive or negative "valence" in the study in Nature. Using experiments with mice and the gene-editing CRISPR tool, researchers found that neurotensin is the primary force in determining the positive or negative label.

"We've basically gotten a handle on the fundamental biological process of how you can remember if something is good or bad," says senior author Kay Tye, per Genetic Engineering & Biotechnology News. "This is something that's core to our experience of life, and the notion that it can boil down to a single molecule is incredibly exciting." Others not involved in the study share the enthusiasm: The study is "extraordinary" and will shape our understanding of fear and anxiety, Florida State University's Wen Li tells Quanta. Of note: The brain's default setting seems to mark memories as negative, perhaps as an ancient survival mechanism—those berries made me sick, so I'll avoid them.

Tye had previously discovered that certain neurons played a role in the process, one set for positive memories and another for negative. "We found these two pathways—analogous to railroad tracks—that were leading to positive and negative valence, but we still didn't know what signal was acting as the switch operator to direct which track should be used at any given time," she explains, per GEBN. The new study concludes that neurotensin is the switch operator. Oregon Health and Science University neuroscientist Vincent Costa, not involved with the study, spells out the potential to STAT News: "If you were to develop drugs around neurotensin receptors, you might expect to have therapeutic implications." (More discoveries stories.)