New study shows how acetylcholine helps the brain to learn effectively

A new study published in Nature Scientific Reports by researchers in Spain and Sweden helps us better understand how the brain learns to choose the right actions in complex situations.

Using a computational model of the striatum – a key brain region for decision-making and learning from rewards – the team found that the neuromodulator acetylcholine may work together with dopamine to fine-tune learning in the brain’s action-selection circuits. While dopamine has long been known to encode reward prediction errors, the study proposes that acetylcholine acts like a timing gate, opening brief windows during which only the neurons involved in the just-executed action learn from the result.

This mechanism helps the brain focus its learning on the most relevant behaviour, avoiding interference from competing signals. In the model, this acetylcholine-based process worked with dopamine to create a biologically realistic learning rule that improved performance across complex tasks. The study also points to complementary roles for two types of striatal neurons: one group strengthens successful action patterns, while the other helps suppress outdated ones. The research, which received support from the EBRAINS 2.0 project, provides a clearer picture of how the brain’s chemical messengers work together to make learning more efficient – and could inspire new ideas for artificial intelligence systems that learn in a similarly selective way.

Read the full paper:

González-Redondo, Á., Garrido, J.A., Hellgren Kotaleski, J. et al. Cholinergic modulation enables scalable action selection learning in a computational model of the striatum. Sci Rep 15, 34902 (2025). https://doi.org/10.1038/s41598-025-18776-3