NCT05103176

Brain State-dependent Stimulation to Improve Movement

Leveraging Behavioral State to Enhance Specificity of Non-invasive Brain Stimulation on Motor Circuits

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 59 (actual)
• Sponsor: University of Michigan · Academic / Other
• Sex: All
• Age: 18 Years – 50 Years
• Healthy volunteers: Accepted

Summary

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.

Detailed description

This study will examine a particular type of rTMS, known as theta burst stimulation (TBS), which has been shown to induce longer lasting effects than other forms of rTMS, making TBS an important tool for therapeutic applications. While TBS provides relatively focal stimulation, effects on the brain occur through interconnected networks in ways that are poorly understood. Moreover, stimulation is highly state-dependent, and the use of rTMS in most therapeutic settings, such as the treatment of motor impairments, leaves behavioral state uncontrolled. Augmenting rTMS therapy by inducing specific behavioral states is an attractive idea for improving therapeutic rTMS, but the relevant knowledge base is sparse. To address this critical gap, this exploratory R21 proposal will examine the effects of TBS and behavioral state on brain and motor behavior. The investigators will test the broad hypothesis that when TBS is applied during a controlled behavior state, motor function will be facilitated, compared to stimulation when behavioral state is uncontrolled. The investigators will focus on the posterior parietal cortex (PPC), and associated parietofrontal circuits, which subserve skilled grasp control, an ability known to be impaired in stroke, traumatic brain injury, and other motor disorders. The investigators will collect functional magnetic resonance imaging (fMRI), neurophysiological measures with TMS, and behavioral measures in all subjects for three different interventions. In Aim 1, the investigators will show improvement in action performance by manipulating the behavioral state during PPC stimulation. In Aim 2, the investigators will demonstrate modulation of neurophysiological aftereffects of PPC stimulation on motor output by manipulating behavioral state. In Aim 3, the investigators will assess the relationship between brain connectivity, plasticity and behavior in response to the behavioral state during brain stimulation. Impact: Results will provide insights into the effects of rTMS and behavioral state on the brain and behavior. This knowledge will lay a mechanistic foundation for future studies to show how controlling behavioral state during rTMS can improve therapeutic efficacy in neurological disorders.

Conditions

• Healthy

Interventions

Type	Name	Description
DEVICE	TMS	A MagPro X100 magnetic stimulator with a 90mm figure-8 coil (MC-B70, MagVenture Inc.) will be utilized to deliver brain stimulation. All participants will receive five consecutive days of stimulation. The 3-minute session of intermittent Theta Burst Stimulation (iTBS) will consist of 10 bursts of high-frequency stimulation (a 2 s train of 3 biphasic waveform pulses at 50 Hz repeated every 200 ms at 80% AMT) repeated every 10 s for a total of 190 s (600 pulses) to the target area. The target area will be located using BrainSight2 neuronavigation system. The baseline structural scan obtained during the scan 1 will be utilized for this localization process.
BEHAVIORAL	Object directed grasping	Subjects will perform a precision grip with the right hand towards either a small or large target object positioned in front of them. The illumination of an LED (green or red) will instruct the subject to plan a precision grip towards either a small or large target object positioned in front of them. After \~1 second, the LED will extinguish and cue subjects to execute the intended object-directed hand action. The presentation of the visual stimuli will be synchronized with the iTBS stimulation, which will occur 800ms before the onset of every "GO" cue in order to modulate cortical activity during both the planning and execution phase of the action.

Timeline

• Start date: 2022-02-15
• Primary completion: 2023-05-31
• Completion: 2023-05-31
• First posted: 2021-11-02
• Last updated: 2025-04-04
• Results posted: 2025-04-04

Locations

1 site across 1 country: United States