A research team at The University of Osaka has identified a crucial brain region involved in motor learning during reaching movements. The parvocellular division of the red nucleus, a small but specialized structure in the midbrain, was found to generate and transmit “error signals” necessary for adapting hand movements. This discovery clarifies a long-standing question in neuroscience about how the brain detects and corrects motion inaccuracies, with potential applications in developing new rehabilitation methods.