New Brain Learning System Uncovered, Shedding Light on Habits and Parkinson’s

New Brain Learning System Uncovered, Shedding Light on Habits and Parkinson’s
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Scientists at the Sainsbury Wellcome Centre, University College London, have discovered a second brain learning system that explains how habits form and why they can be difficult to break, SciTech Daily reported. Published in Nature, the study reveals that the brain uses two dopamine-driven processes: the well-known reward prediction error (RPE) and a newly identified action prediction error (APE).

RPE helps the brain learn by evaluating whether outcomes are better or worse than expected, guiding value-based decisions. In contrast, APE tracks how often an action is repeated, allowing habits to form by reinforcing frequently chosen behaviors. This dual system enables people to perform routine tasks automatically, freeing up mental resources for other activities.

Using experiments with mice, researchers showed that when the brain region called the tail of the striatum, responsible for APE, was impaired, animals struggled to develop habitual behaviors despite learning basic tasks. This finding provides insight into why habits persist and why breaking them can be challenging.

The discovery also has implications for Parkinson’s disease, where the loss of movement-related dopamine neurons may explain patients’ difficulty with habitual actions like walking, while flexible behaviors remain intact.

Lead researcher Dr. Marcus Stephenson-Jones emphasized that this new understanding opens avenues for treating addiction, compulsions, and Parkinson’s by targeting the brain’s habit system. Further research will explore how these two learning systems interact and how habits can be modified.