Motor learning in health, ageing and disease

Abstract

Motor adaptation functions to update learned, goal-directed movements in response to predictable environmental or bodily changes to ensure actions remain useful throughout life. However, it has been suggested that this process becomes impaired with advancing age and illnesses such as Parkinson’s disease. The primary aim of this project, as such, is to characterise these impairments and identify potential contributing factors. The secondary aim is to develop an animal model of forelimb adaptation, allowing its study across the rodent lifespan.
In Chapter 2, the relationship between task-relevant movement variability, sensory uncertainty and motor adaptation in young adults is examined. Results suggest movement variability and sensory uncertainty are associated with slower and less efficient adaptation, respectively.
With these factors in mind, Chapters 3 and 4 investigate the effect of age and Parkinson’s disease on motor adaptation. Results of the former suggest that older adults retain the ability to adapt to novel perturbations, albeit to a lesser extent than younger adults. Results of the latter suggest that patients with moderate Parkinson’s disease display slower adaptation and aftereffects of a reduced magnitude when compared with age-matched controls.
Finally, Chapter 5 evaluates a novel model of forelimb motor adaptation in rats. Pilot data suggest the task successfully generates hallmarks of adaptation in young animals. However, follow-up experiments in both young and aged animals do not replicate this result.
To summarise, movement variability and feedback quality negatively influence motor adaptation in young and aged adults. In addition, although the ability to adapt to sensory perturbations persists with advancing age and moderate Parkinson’s disease, noticeable impairments are present. Finally, there remains a need for a true forelimb adaptation task for freely-moving rats.

Date of Award	21 Jun 2022
Original language	English
Awarding Institution	University of Bristol
Supervisor	Iain D Gilchrist (Supervisor) & Richard Apps (Supervisor)