How does the brain decide what memories are good and bad? A new mouse study offers clues
SAN DIEGO — Your first kiss. The blissful cool of ice cream. That time you smashed your finger while shutting the car door. Life is full of memories that we instinctively and instantly label as good or bad. In a new study, scientists took a key step toward unraveling how our brain assigns positive or negative emotions to our experiences.
Researchers at the Salk Institute working in mice found that a signaling molecule called neurotensin profoundly shaped whether the animals associated cues in their environment with positive or negative stimuli. Eliminating neurotensin in certain brain cells enhanced fear-based responses and blunted reward-based learning. And driving up levels of neurotensin had the opposite effect.
