Changes to task relevance in redundant motor environments distinguish structure learning from adaptation

In two monkeys learning a 3D-to-2D redundant visuomotor mapping, relevance-altering (RA) perturbations shifted learning from rapid online adaptation to slower offline structure learning.

• Why it matters: Motor control redundancy requires learners to infer which movement dimensions affect outcomes, but how learning computations change when the task-relevant space shifts is unclear.
• What they did: Monkeys trained a 3D hand position to 2D cursor mapping, then received relevance-preserving (RP) perturbations that rotated within the learned task-relevant space or relevance-altering (RA) perturbations that changed it.
• The result: RP was learned rapidly online and generalized to the initial mapping, while RA adaptation took longer, relied on offline learning, did not generalize, and improved faster across repeated RA mappings with altered movement generation.