Two influential paradigms, sensorimotor adaptation and eyeblink conditioning, have deepened our understanding of the theoretical and neural foundations of motor learning, and in particular, the role of the cerebellum. Although there has been some cross-pollination between these two lines of research, they typically operate within distinct theoretical frameworks, with the incremental updating of an internal forward model explaining adaptation, and associative learning processes explaining eyeblink conditioning. Here we ask if a unified framework might be parsimonious, directly linking sensorimotor adaptation to associative learning. Using a task that isolates implicit sensorimotor adaptation, we paired movement-related feedback with neutral auditory or visual cues that served as conditioning stimuli (CSs) to test two key signatures of associative learning- differential conditioning and compound conditioning. We observed clear Pavlovian effects in both cases: Implicit trial-by-trial changes in movement kinematics were reliably modulated by the CSs in the predicted directions. Moreover, after compound conditioning, we observed a robust negative correlation between the responses of individuals to the two elemental CSs of the compound, consistent with the additivity principle posited by the Rescorla-Wagner model of classical conditioning. Computational modelling demonstrates that these results cannot be captured by the conventional algorithm used to explain the operation of a forward model. We believe that associative learning effects in implicit sensorimotor adaptation provide a proof-of-concept for linking multiple motor learning paradigms within a similar theoretical framework.
bioRxiv Subject Collection: Neuroscience