Researchers at the City University of New York (CUNY) identified a brain mechanism that regulates learning and adaptation in adults.
How the Smoothened receptor controls learning flexibility
The study, published recently in the journal iScience, found that the Smoothened receptor acts as a time regulator in the adult brain by coordinating dopamine and acetylcholine activity in the striatum. This brain region links actions with outcomes and evaluates the effort needed to achieve them. Andreas H. Kottmann, director of the study, explained that by adjusting the duration of acetylcholine pauses, Smoothened determines how strongly dopamine can reinforce recent actions in the adult brain.
What happens when Smoothened is absent
Experiments showed that animals lacking Smoothened in cholinergic neurons learned motor tasks faster and persisted longer in reward-seeking behavior. However, this advantage came with a trade-off: they lost the ability to adapt when conditions changed. Kottmann noted that Smoothened appears to act as a regulator that prevents reinforcement signals from becoming too strong or persistent.
Why this matters for neurological conditions
The findings, which link biology to mental flexibility in adulthood, have direct implications for diseases like Parkinson’s and addiction. When Smoothened activity is high, acetylcholine pauses are shorter and regulated; when the receptor is removed, pauses lengthen, extending the time dopamine can drive changes. The balance between learning and flexibility depends on the fine-tuning between these two substances.
What is the Smoothened receptor’s role in the adult brain?
It acts as a time regulator that coordinates dopamine and acetylcholine activity to determine the intensity of reinforcement for recent actions.
How does removing Smoothened affect learning and adaptation?
Animals lacking Smoothened learn faster and persist longer in reward-seeking but lose the ability to adapt when conditions change.