Behavioural and Cognitive Neuroscience (Beacon) Seminar: Reward in the motor system

The impact of reward on motor behaviour has gathered extreme interest over the last decade as beneficial effects have been shown on execution, learning and retention. To explain such results, it has been suggested that reward leads to dopamine-dependent habitual-like behaviour (Haith and Krakauer, 2013), making it a promising tool for rehabilitation. This talk introduces an alternative hypothesis which proposes that the beneficial effects of reward are mainly driven by the greater engagement of cognitive control. Using a range of behavioural tasks, we show that reward-based improvements in memory retention are driven by the development and expression of an cognitive-strategy that is strongly linked to spatial working memory capacity (Codol et al., 2018; Holland et al., 2018). Next, we show that the trial-by-trial effects of reward on reaching performance (enhanced accuracy and speed) can be, at least partially, explained through increased muscle co-contraction, another possible cognitive-strategy. Finally, we show that reward-based effects on complex sequential actions have initial transient properties, more akin to cognitive control, but which over time appear to become more habitual (reward-based motor chunking). These conclusions are discussed in the context of rehabilitation and specifically in the importance of accounting for reward-based cognitive-control mechanisms.