Adapting to new situations means the brain must change old behaviors. Scientists have been trying to understand how this flexibility works.
Researchers at the Okinawa Institute of Science and Technology (OIST) used special imaging to watch brain cells. They saw how these cells release a chemical called acetylcholine when mice change their choices after not getting an expected reward.
Acetylcholine and Changing Habits
It's important to adjust how we act based on the situation. This skill helps us in daily life, from work to personal interactions. Sometimes, adapting quickly can even be a matter of survival.
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Start Your News DetoxA new study in Nature Communications looked at how mice change their behavior. The findings might help us understand conditions like addiction, obsessive-compulsive disorder (OCD), and Parkinson’s disease.
Professor Jeffery Wickens, who leads the Neurobiology Research Unit at OIST, explained that the brain mechanisms for changing behaviors are very complex. They involve many parts of the brain working together.
Previous studies suggested that brain cells called cholinergic interneurons, which release acetylcholine, help with behavioral flexibility. The OIST team used advanced imaging to see this chemical release in real time.
The Chemical Signal of Disappointment
To see how the brain reacts to unexpected changes, researchers trained mice in a virtual maze. The mice learned which path led to a reward. Then, the scientists suddenly changed the correct path. This meant the mice didn't get the reward they expected.
The team used two-photon microscopy to watch brain activity during this surprising moment.
Dr. Gideon Sarpong, the study's first author, noted that acetylcholine release significantly increased in certain brain areas. Behaviorally, more mice showed "lose-shift" behavior, meaning they changed their choices after not getting a reward.
The more acetylcholine increased, the more likely mice were to change their future choices. This showed how important acetylcholine is for breaking habits and making new choices.
To confirm acetylcholine's role, researchers lowered the mice's ability to produce the chemical. When acetylcholine levels dropped, the mice were much less likely to change their decisions after missing a reward. This proved that acetylcholine helps the brain adapt to new conditions.
While most cholinergic interneurons released more acetylcholine, some small groups of cells showed little change or even a decrease. Researchers think these areas might help the brain remember old successful paths. Dr. Sarpong suggested this means mice might not forget previous reward paths, but keep that information in case the situation changes again.
Understanding Brain Disorders
The researchers stressed that many brain systems work together for behavioral flexibility. These findings are an important part of the puzzle, but not the whole picture. Other brain regions, cells, and chemicals also help control how behavior changes.
Professor Wickens highlighted that the striatum, where these cholinergic interneurons are found, is a key part of this system.
This research could also have practical uses in medicine. Understanding how acetylcholine affects behavior might lead to better treatments for several brain and mental health conditions.
Professor Wickens explained that acetylcholine levels are often different in treatments for conditions like Parkinson’s disease or schizophrenia. So, understanding this chemical is vital for treating many neuropsychiatric disorders. He added that in conditions like addiction and OCD, people often struggle to break habits. Learning about behavioral flexibility could help develop better treatments for these issues.
Deep Dive & References
Spatially heterogeneous acetylcholine dynamics in the striatum promote behavioral flexibility - Nature Communications, 2025
