Optimizing motor memories with unpredictable reward

Foundational animal work on schedules of reinforcement shows that the predictability of reward is crucial for determining the retention of learned behaviours. Predictable rewards lead to rapid extinction once reinforcement stops. In contrast, unpredictable rewards produce more persistent behaviour change. Despite this, there has been no systematic investigation of how reward predictability can be exploited to optimise motor memory in humans. This omission represents a critical gap that may limit the effectiveness of reward based strategies across health and disease.

The aim of this project is to determine how the predictability of reward shapes motor retention in humans. The central hypothesis is that unpredictable reinforcement schedules during reward-based motor learning support more robust and persistent motor memories than predictable schedules. To test this hypothesis, we will pursue three objectives. Obj.1 is to quantify how distinct reinforcement schedules influence short and long term retention of a newly learned action. Obj.2 is to identify neural mechanisms linking reward predictability to motor retention, using fMRI. Obj.3 is to examine whether the reinforcing effect of reward can be mimicked with non invasive brain stimulation by targeting the striatum with transcranial ultrasound stimulation.

By understanding the mechanisms that link reward predictability to motor retention, this project will provide a novel foundation for designing more effective reward-based neural and behavioural interventions.

Funding notes:

This is a PhD studentship with the Midlands Integrated Biosciences Training Partnership, funded by BBSRC and in partnership with the University of Warwick, University of Birmingham, Aston University, Harper Adams University, Coventry University, and the University of Leicester.

References:

• Sporn, Galea. Reward-based improvements in motor sequence learning are differentially affected by dopamine. PLOS one
• Hamel, Pearson, Sifi, Patel, Hinder, Jenkinson, Galea. The intracortical excitability changes underlying the enhancing effects of rewards and punishment on motor performance. Brain Stimulation
• Codol, Kashefi, Forgaard, Galea, Pruszynski & Gribble. Sensorimotor feedback loops are selectively sensitive to reward. eLife
• Codol, Holland, Manohar & Galea. Reward-based improvements in motor control are driven by multiple error-reducing mechanisms. Journal of Neuroscience