Last updated on July 2020

Mechanism of Non-invasive Magnetic Stimulation


Brief description of study

Background

Transcranial magnetic stimulation (TMS) is form of non-invasive brain stimulation. It is approved to treat depression. TMS may help decrease drug craving. It is important to understand how TMS affects the brain. Such a better understanding would help to design ways to treat drug addiction.

Objectives

To learn how TMS affects the brain when it stimulates an area in the front of the brain. Also, to see how the stimulation affects the area stimulated and other connected areas.

Eligibility

Healthy, right-handed adults ages 18 60 who are non-drug users.

Design

Participants will be screened under protocol 06-DA-N415.

Participants will have at least 3 visits. The first visit will last about 3 hours. All other visits will last up to 6 hours. Participants cannot use drugs or alcohol at least 24 hours before a visit. They cannot have more than half a cup of a caffeinated drink at least 12 hours before a visit.

Each visit will include a brief medical history update, urine test for drugs and pregnancy (if female), a breath test for alcohol and smoking, and questionnaires.

Participants will have a TMS orientation visit. A wire coil will be placed on the head. An electrical current will pass through the coil to create a magnetic pulse that stimulates the brain.

The other visits will include 2 sessions of TMS-MRI. Participants will lie on a table that slides into a cylinder. The TMS coil and the MRI coil will be placed over the head. Pictures will be taken of the brain with and without stimulation.

Participants will complete a questionnaire about how they feel before and after each TMS session and in a follow-up call 2 3 weeks after their last session.

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Detailed Study Description

Objectives: The goal of the protocol is to investigate acute modulations of brain activity by transcranial magnetic stimulation (TMS). Using simultaneous TMS and functional magnetic resonance imaging (fMRI), we will evaluate TMS induced changes in brain activity, including regional brain activation and inter-regional functional connectivity. Repetitive TMS will be applied over the dorsolateral prefrontal cortex (DLPFC) with different frequencies and interleaved with fMRI acquisition to provide online monitoring of brain activity. Furthermore, we will assess the relationship between the TMS induced brain activity and the anatomical connection obtained from diffusion tensor imaging (DTI), using individual variations in these imaging measures. Results from this study will help to understand the underling mechanism of TMS and will provide insights for interpretation of TMS and fMRI data.

Study population: Up to 70 healthy, adults will be tested. Subjects must fit exclusion/inclusion criteria for both TMS and MRI. We expect to enroll 70 subjects to arrive at 50 who complete the protocol.

Design: The study is a within-subject design with each subject completing up to 4 TMS-fMRI sessions in two days (2 sessions per day)

Outcome measures: The outcome measures will be the effects of TMS on fMRI blood oxygen level-dependent (BOLD) responses, TMS induced changes on resting state functional connectivity, and their associations with relevant structural connectivity revealed by DTI.

Clinical Study Identifier: NCT03394066

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Recruitment Status: Open


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