3 Clinical Trials for Various Conditions
Objective When learning to tap to a rhythm the brain has to coordinate information from different senses (eyes, ears, touch). This information has to be integrated into a movement plan to allow a smooth, continuous performance. Two brain areas that are of particular interest for this task are the posterior parietal cortex that integrates sensory and motor information and the primary motor cortex that sends out the movement commands to the muscles. These areas communicate via nerve connections with each other. The goal of this research proposal is to examine if the strength of the connection between those areas can be changed by practicing a simple tapping task and if the change in connection strength depends on if the rhythms were shown by visual or auditory stimuli. Additionally we will investigate how the ability to tap rhythms relates to other cognitive abilities like problem solving. Study Population We intend to study 20 adult healthy volunteers on an outpatient basis. Design In three experimental sessions we propose to use transcranial magnetic stimulation (TMS) and electro encephalography (EEG) to examine the role of the posterior parietal cortex in motor learning. In session 1 a neurological examination will be performed and a clinical and anatomical MRI (Magnet Resonance Image) will be taken. Session 1 can be skipped if an MRI and a neurological exam have been performed at the NIH during the last year. In session 2 TMS will be used to examine the connection between posterior parietal cortex and primary motor cortex before and after rhythm training. Additionally, EEG will be recorded during the training session. In session 3 we will examine how the ability to tap to different beats relates to higher cognitive functions. We will record EEG during tapping simple beats and we will administer a pen and paper problem-solving test. Outcome Measures In session 2 the primary outcome measure will be change in conditioned Motor Evoked Potential (MEP) peak-to-peak amplitude after learning temporal motor sequences measured in the primary motor cortex. A secondary outcome measure will be the interregional coherence changes as measured by EEG during training. In session 3 the primary outcome will be performance on the tapping task and on the pen and paper test as well as the interregional coherence changes as measured by EEG during the tapping task.
Motor adaptation and generalization are believed to occur via the integration of various forms of sensory feedback for a congruent representation of the body's position in space along with estimation of inertial properties of the limb segments for accurate specification of movement. Thus, motor adaptation is often studied within curated environments incorporating a "mis-match" between different sensory systems (i.e. a visual field shift via prism googles or a visuomotor rotation via virtual reality environment) and observing how motor plans change based on this mis-match. However, these adaptations are environment-specific and show little generalization outside of their restricted experimental setup. There remains a need for motor adaptation research that demonstrates motor learning that generalizes to other environments and movement types. This work could then inform physical and occupational therapy neurorehabilitation interventions targeted at addressing motor deficits.
Repetitive transcranial magnetic stimulation (rTMS) is a powerful tool to non-invasively modulate brain circuits, brain plasticity, and behavior. This proposal will test the hypothesis that controlling behavioral state during focal multi-day rTMS of a brain region involved in grasping movements will enhance the functional specificity of the neuromodulation action among distributed brain regions involved in voluntary motor control and concomitantly improve manual dexterity. Results from this study will be used to optimize rTMS therapy for individuals with neuromotor impairments by controlling behavioral state to improve the efficacy of rTMS treatment. Healthy volunteers that qualify for this study will have motor skill assessments and basic neuromotor testing (using neurophysiology with TMS and functional Magnetic Resonance Imaging (fMRI) scans). Participants will be asked to come in for up to nine sessions that include 1 screening session, 5 consecutive daily rTMS sessions and 3 assessment sessions with resting-state and task-based fMRI, neurophysiology with TMS, and hand motor tasks over the course of 3-4 weeks.