This study investigates the effects of sub-maximal exercise to task-failure (e.g., fatigue) with the less involved, or so-called non-paretic hand, in people who have experienced a stroke. In previous work the investigators found that non-paretic hand exercise to task-failure increased excitability of the motor cortex in the more involved hemisphere and produced behavioral improvements in the unexercised paretic hand. Importantly, the magnitude of increased brain excitability is greater than what has been observed following brain stimulation with either repetitive transcranial magnetic stimulation (TMS) or transcranial direct current stimulation (tDCS) and lasts longer. This approach could be implemented in the clinical setting and could be accessible to a greater number of people than brain stimulation. The investigators' goals in the current study are to: repeat previous findings in a different group of participants and investigate the neural mechanisms that produce brain and behavioral facilitation in order to inform development of this approach for clinical implementation.
The long-term goal is to restore upper extremity (UE) motor function following stroke. The overall objective of this proposal is to improve the investigators' understanding of neural mechanisms contributing to inter-limb and inter-hemispheric transfer following non-paretic limb exercise to task failure. The investigators will use transcranial magnetic stimulation to probe acute adaptations in cortical excitability, intracortical and inter-hemispheric circuits that accompany behavioral facilitation of the paretic hand.
The work proposed in this two year project will enable the investigators to obtain three data elements critical to complete the working hypothesis:
1. . Changes in intracortical and interhemispheric inhibition in both hemispheres following non-paretic limb exercise to task-failure.
2. . Behavioral effects using a motor task involving manipulation and dexterity.
3. . Determine the persistence and consistency of neural and behavioral facilitation.
- Submaximal exercise (grip) Other
Intervention Desc: participants perform repeated gripping with visual feedback to task failure ARM 1: Kind: Experimental Label: Stroke Description: individuals with upper-extremity impairment following stroke
please see inclusion criteria
|Type||Measure||Time Frame||Safety Issue|
|Primary||Short Intracortical Inhibition (SICI)||baseline, post task-failure (minutes to an hour), every 45 min up to 3.5 hours post-task-failure (7 points total)|