The relationship between reinforcement and explicit strategies during visuomotor adaptation

Abstract

The motor systems ability to adapt to changes in the environment is essential for maintaining accurate movements. During such adaptation several distinct systems are recruited: cerebellar sensory-prediction error learning, success-based reinforcement, and explicit strategy-use. Although much work has focused on the relationship between cerebellar learning and strategy-use, there is little research regarding how reinforcement and strategy-use interact. To address this, participants first learnt a 20{degrees} visuomotor displacement. After reaching asymptotic performance, binary, hit-or-miss feedback (BF) was introduced either with or without visual feedback, the latter promoting reinforcement. Subsequently, retention was assessed using no-feedback trials, with half of the participants in each group being instructed to stop using any strategy. Although BF led to an increase in retention of the visuomotor displacement, instructing participants to remove their strategy nullified this effect, suggesting strategy-use is critical to BF-based reinforcement. In a second experiment, we prevented the expression or development of a strategy during BF performance, by either constraining participants to a short preparation time (expression) or by introducing the displacement gradually (development). As both strongly impaired BF performance, it suggests reinforcement requires both the development and expression of a strategy. These results emphasise a pivotal role of strategy-use during reinforcement-based motor learning.