Investigating the impact of executive function on complex motor control strategies

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For many years, gait was primarily thought of as an automatic motor task with little cognitive input, it is only recently that have we come to realize the impact of cognitive function on locomotor control. In fact, most of our daily activities require our central nervous system to coordinate our motor actions while simultaneously processing external information about our environment and surroundings.For example, consider crossing a busy street, which requires us to observe the traffic flow, and adjust our locomotion patterns to the surrounding environment. This series of tasks actually requires a high level of cognitive involvement, termed executive function; in addition, we routinely execute these complex movement patterns while also performing a thinking task, e.g. generation of a shopping list. These locomotorcognitive interactions can be described as dual-task performance. Emerging evidence has also suggested the importance of executive function in the control of other complex motor tasks, such the generation of reactive recovery steps by the central nervous system following an external perturbation. Given that multi-tasking is becoming increasingly more common in our activities of daily living (e.g. talking on cell phone while walking) dual-task paradigms offer an interesting perspective towards understanding attentional demands of complex motor tasks. As sub-optimal performance can present serious threats to our stability, it is logical to ask if dual-task performance can be improved with practice; until recently however, little was known about what constitutes an effective practice strategy to improve concurrent performance of complex motor tasks. Thus the long term objective of my research is to advance our understanding of the mechanisms behind visuomotor control and the role that cognitive resources play in the execution of adaptive control strategies used to maintain dynamic stability. The short term objectives over the next five years are to: (i) discover the optimal number of practice sessions and assess the retention of improved dual-task performance for an obstacle avoidance motor task (Study I), (ii) explore novel dual-task practice modalities for this motor task (Study II); (iii) ascertain effective dual-task practice strategies for a reactive stepping task (Study III), and (iv) discover the optimal number of practice sessions and assess the retention of improved dual-task performance for a reactive stepping task (Study IV).This research has both theoretical and practical importance; it will help elucidate competing theories of cognitive attention and identify strategies to improve concurrent performance of demanding motor and cognitive tasks.