Manipulating Valence

Without neurotensin signaling in the BLA, mice could no longer assign positive valence and didn’t learn to associate the first tone with a positive stimulus. Interestingly, the absence of neurotensin did not block negative valence. The animals instead became even better at ne...

For a human or animal to learn whether to avoid, or seek out, a particular experience again in the future, their brain must associate a positive or negative feeling, or “valence” with that stimulus. The brain’s ability to link these feelings with a memory is called “valence a...

In 2016, Kay Tye, today a professor in Salk’s Systems Neurobiology Laboratory and a Howard Hughes Medical Institute Investigator, discovered that a group of neurons in the brain’s basolateral amygdala (BLA) helps assign valence when mice are learning. One set of BLA neur...

The findings suggest that the brain’s default state is to have a bias toward fear—the neurons associated with negative valence are activated until neurotensin is released, switching on the neurons associated with positive valence. From an evolutionary perspective, Tye says,

“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. “This is something that’s core to our experience of life, and the notion that it can boil down to a single molecule is ...