Quattrocchi, Graziella; (2018) Role of reward and punishment in motor learning in health and after stroke. Doctoral thesis (Ph.D), UCL (University College London).

Preview

Text PhD_Thesis_GQ_Feb_2018.pdf - Accepted Version Download (4MB) | Preview

Abstract

Is the carrot more effective than the stick? Through a combination of behavioural experiments, pharmacological manipulations and computational modelling, this thesis investigates the effects of reward and punishment feedback on adaptive motor learning, in both healthy subjects and stroke survivors. The role of error-based motor learning in neurorehabilitation is still unclear partly because, although it leads to fast and large changes in behaviour, these changes are often short-lived once the perturbation is removed. Nevertheless, recent evidence shows that motivational feedback can increase adaptation to a perturbation and retention of the motor memory in healthy subjects. In the first study presented in this thesis I show that these effects partially apply also to stroke survivors. In particular, reward or punishment-based feedback enhance error-correction during adaptation, and reward increases the retention of the new motor memory in stroke survivors. I then moved to investigate the role of dopamine in error-based motor learning under reward or punishment in healthy young subjects. Consistently with results in stroke patients, reward increased motor memory retention. In addition, I show here that this effect of reward on retention is mediated by dopaminergic pathways. Finally, I investigated if pharmacologic dopaminergic stimulation can potentiate the positive effect of reward on retention in dopamine-deficient subjects, such as older adults. Unfortunately, likely due to the dopaminergic deficit, reward had no effect on elderly participants, and this study failed to show a benefit of dopaminergic stimulation in the elderly. However, this evidence is not sufficient to rule out possible positive effects of pharmacologic dopaminergic stimulation on motor learning in brain injured patients, such as stroke survivors. Taken together, these results represent a step further toward the combined use of reward feedback, pharmacological stimulation and motor learning paradigms in clinical rehabilitation. Indeed, as shown by the qualitative survey presented at the beginning of this thesis, an evidence-based guide to the use of reward and punishment feedback during rehabilitation would be welcome by stroke professionals.

Download activity - last month

Export as JSONXMLCSV

Download activity - last 12 months

Export as JSONCSVXML

Downloads by country - last 12 months

Export as JSONXMLCSV

Archive Staff Only

View Item