Effects of rTMS on Human Brain Activity Measured With fMRI

Study Overview
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Brief Summary
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This project investigates the effects of repetitive transcranial magnetic stimulation (rTMS) on neural circuits as a function of spatiotemporal parameters and brain state in order to better understand why the method works and how to improve its efficacy. Leveraging our expertise in application of TMS methodology during concurrent single neuron recording techniques in non-human primates and imaging and scalp potential techniques in humans, the investigators aim to resolve three interlocking problems in the design and application of rTMS: stimulation frequency, spatial targeting, and interactions with brain state.

Official Title
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Effects of rTMS on Human Brain Activity Measured With fMRI

Conditions
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Human Brain Activity

Intervention / Treatment
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* Device: Repetitive TMS


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age between 18-30. Use of effective method of birth control for women of childbearing capacity. Willing to provide informed consent. Exclusion Criteria: Current or recent (within the past 6 months) of substance abuse or dependence, excluding nicotine and caffeine (urine test). Current serious medical illness (self report). History of seizure except those therapeutically induced by ECT (childhood febrile seizures are acceptable and these subjects may be included in the study), history of epilepsy in self or first degree relatives, stroke, brain surgery, head injury, cranial metal implants, known structural brain lesion, devices that may be affected by rTMS or MRI (pacemaker, medication pump, cochlear implant, implanted brain stimulator); [TMS Adult Safety Screening (TASS) form]. Subjects are unable or unwilling to give informed consent. Diagnosed any Axis I DSM-IV disorder (MINI, DSM-IV) Subjects with a clinically defined neurological disorder including, but not limited to: Any condition likely to be associated with increased intracranial pressure Space occupying brain lesion. History of stroke. Transient ischemic attack within two years. Cerebral aneurysm. Dementia. Mini Mental Status Exam (MMSE) score of <24. Parkinson's disease. Huntington's disease. i. Multiple sclerosis. Increased risk of seizure for any reason, including prior diagnosis of increased intracranial pressure (such as after large infarctions or trauma), or currently taking medication that lowers the seizure threshold. Subjects with cochlear implants Subjects not willing to tolerate the confinement associated with being in the MRI scanner. Women who are pregnant or breast-feeding (urine test). Blindness. Inability to read or understand English.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 30 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Non-Randomized
Intervention Model: Factorial Assignment
Interventional Model Description: The study is a within-subjects design focused on estimating the fMRI BOLD response to different levels of TMS intensity. The conditions in the study (arms) are repeated within each participant (20%, 40%, 80%, or 120% of an individual's titrated resting motor threshold).
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Dose-response TMS - Intensity = 20%RMT<br>Four levels of TMS intensity (here, 20% of Resting Motor Threshold), titrated to each individual, tested within the MRI. Outcome measures include accuracy, RT, and BOLD signal. | Device: Repetitive TMS<br>* 1-10 Hertz rTMS will be administered<br>|
| Experimental: Dose-response TMS - Intensity = 40%RMT<br>Four levels of TMS intensity (here, 40% of Resting Motor Threshold), titrated to each individual, tested within the MRI. Outcome measures include accuracy, RT, and BOLD signal. | Device: Repetitive TMS<br>* 1-10 Hertz rTMS will be administered<br>|
| Experimental: Dose-response TMS - Intensity = 80%RMT<br>Four levels of TMS intensity (here, 80% of Resting Motor Threshold), titrated to each individual, tested within the MRI. Outcome measures include accuracy, RT, and BOLD signal. | Device: Repetitive TMS<br>* 1-10 Hertz rTMS will be administered<br>|
| Experimental: Dose-response TMS - Intensity = 120%RMT<br>Four levels of TMS intensity (here, 120% of Resting Motor Threshold), titrated to each individual, tested within the MRI. Outcome measures include accuracy, RT, and BOLD signal. | Device: Repetitive TMS<br>* 1-10 Hertz rTMS will be administered<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Motion Perception Accuracy | Acute effect of a rTMS session on the performance for a motion task, as measured by accuracy (in percentage of correct responses) | during each TMS session, up to 3 hours | 
| Reaction Time | Acute effect of a rTMS session on the performance for a motion task, as measured by reaction time (in ms) | during each TMS session, up to 3 hours | 
| Activation of Cortical Networks During a Visual Motion Task. | Acute effect of a rTMS session on fMRI activation during a motion task, as measured by the change in BOLD signal | during each TMS session, up to 3 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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TMS, BOLD activity, Network activity