How the adult brain learns when to persist and when to change.

This article focuses on new research identifying the Smoothened receptor as a key regulator of dopamine and acetylcholine signaling in the adult brain, particularly within the striatum, a region involved in learning and behavior adaptation. The study found that Smoothened controls the timing of pauses in acetylcholine release by cholinergic interneurons, thereby influencing how strongly dopamine can reinforce behaviors and how flexibly those behaviors can be updated. These findings have implications for neurological disorders such as Parkinson's disease, where disruptions in dopamine and acetylcholine coordination may precede cell loss and motor symptoms, and for addiction, where restoring balance between these neurotransmitters could inform treatment strategies. The research highlights Smoothened as a potential target for addressing altered motivation, habit formation, and reinforcement in brain diseases. [Extracted from the article]