Motor preparation changes with practice

The goal of this dissertation was to examine how the preparation of a movement changes as a result of practice, in order to gain a better understanding of the learning process. To investigate what aspects of a motor action can be prepared in advance, a startle methodology was used as the presentation of a startling stimulus is thought to cause the release of a pre-programmed response. Limits to pre-programming and changes to preparation as a result of learning were examined through practice of movements of varying complexities. Furthermore, movement preparation during physical practice, imagery and observational practice were examined. The use of startle methodology in a learning paradigm allowed for new information regarding the role of motor preparation processes in the learning of novel motor skills. Six experiments are detailed along with their contribution to the advancement of our understanding of what is learned and what is prepared. The first four experiments examined the effects of physical practice on motor preparation and involved movements of varying spatial and temporal characteristics. These experiments provided support that practice results in more accurate pre-programming of motor commands, as well as information pertaining to differences in how spatially targeted and temporally defined movements are prepared. For timing based movements, we found evidence for the reliance on an internal timekeeper, of which the pacemaker pulse is affected by activation level. We also examined the effects of extended physical practice on single component and multiple component movements. In support of previous work, we found multiple element movements had a longer reaction time as compared to single element movements, although this difference was minimized with practice. However, because the startling stimulus triggered all movements at short latencies, we suggested that movement complexity may be more related to the neural commands necessary to produce the movement, rather than a sequencing requirement. The last two experiments examined preparation during motor imagery and observation. Limited support was found during imagery for motor preparation processes that mirror those of intended movements; however observational benefits appeared to be largely perceptual in nature.Education, Faculty ofKinesiology, School ofGraduat