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Optimizing motor memories with unpredictable reward

Secondary Supervisor(s): Prof Davinia Fernández-Espejo

University of Registration: University of Birmingham

BBSRC Research Themes:

• Understanding the Rules of Life (Neuroscience and Behaviour)

Project Outline

Humans possess a remarkable capacity to perform a wide range of movements. Across multiple domains, a key challenge is to maximise long term retention of newly acquired motor skills. Reward based feedback is a powerful method for strengthening memory, and there is growing interest in using reward to improve outcomes. However, most human studies have focused on whether to provide rewards, rather than how those rewards are scheduled over time.

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.