Abstract
Action selection (AS), or selection of an action from a set of alternatives, is an important movement preparation process that engages a frontal-parietal network. The addition of AS demands to arm training after stroke could be used to engage this motor planning process and the neural network that supports it. The purpose of this case series is to describe the feasibility and outcomes associated with task-oriented arm training aimed at engaging the AS behavioral process and the related neural network in three individuals with chronic stroke. Three participants with mild to moderate motor deficits completed 13 to 15 sessions of task-oriented arm training that included AS cues for each movement repetition; cues dictated movement direction, height, or distance. Before and after training, individuals completed an AS brain-behavior probe during functional MRI. AS behavioral performance improved after training (increased accuracy, decreased reaction time) in all participants while brain activation in the AS network (dorsal premotor, parietal, dorsolateral prefrontal cortices) decreased in two participants. Gains in motor function were also found in all three participants, especially on patient-reported measures of perceived difficulty and confidence to complete upper extremity functional tasks. It was feasible to target the AS behavioral process and the related neural network through the addition of AS demands to functional, task-oriented arm training in three individuals with mild to moderate motor dysfunction poststroke.
Highlights
Successful performance of skilled motor tasks involves a variety of movement preparation processes in addition to movement execution
It was feasible to add Action selection (AS) demands to task-oriented arm training in three individuals with mild to moderate motor impairment due to stroke
These findings suggest that these individuals were able to perform the motor preparation process of AS more accurately and more quickly, utilizing less neural resource, after training
Summary
Successful performance of skilled motor tasks involves a variety of movement preparation processes in addition to movement execution. The selection of the action to be performed (e.g., to reach and pick up a cup of water) must occur for the movement parameters to be specified (e.g., descending motor commands to the arm and hand). While some degree of action selection is required for all skilled actions, one can relatively increase AS demands by requiring that a movement response be selected based on an external, abstract visual rule (e.g., selecting to pick up the cup of water from either the low shelf or the high shelf based on an external cue). Task conditions that increase AS demands lead to a longer movement preparation phase and have consistently been shown to engage a network of frontal and parietal brain regions with dorsal premotor cortex (PMd) thought to be a key node in this network [2,3,4,5]. A practice condition that includes AS demands during training has the potential to engage and alter premotor and prefrontal activation
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