TMS With Real-time E-field and EEG Source Imaging

The main goal of this study is to develop and validate an approach to target and stimulate brain networks using transcranial magnetic stimulation using information from magnetic resonance imaging (MRI).

Participants in this study will first be scanned using an MRI scanner to collect data from the brain. The MRI session will take about 40 minutes to acquire anatomical MRI, diffusion MRI, and resting-state functional MRI from the subjects.

Next, the researchers will analyze the MRI data to determine the stimulation areas of each participant. The method will provide two target areas in the brain, including an area in the left dorsolateral prefrontal cortex (DLPFC) and an area in the left inferior parietal lobule (IPL), which are involved in the frontoparietal network related to the executive control functions of the brain.

In the second visit, the participants will take TMS stimulations to the determined brain targets at DLPFC and IPL. The standard intermittent theta-burst (iTBS) protocol will be applied to the targets. To evaluate the effect of TMS stimulations, the participants will perform a computer-based task, named multi-source interference task (MSIT), before the TMS stimulation and another task after the TMS stimulations. The participants will click mouse buttons to respond to instructions in the tasks.

The response time and response error of the tasks will be the outcome measures of this study. The hypothesis is that applying TMS stimulations to the developed brain network targets reduces the response time and response error.

During the TMS stimulations and tasks, electroencephalogram (EEG) data will be collected from the participants. The EEG data, MRI data, and TMS-induced electric field maps will be analyzed and visualized using a software named SlicerTMS. However, the information shown in SlicerTMS will not be used to change the stimulation protocol in this study.

Inclusion criteria

• Age greater than 18 and less than 65 years.
• Able to understand and give informed consent/assent.
• No prior neuropsychiatric, neurological disorders, epilepsy, or seizures.
• No metal implants.
• Absent of lesions or tumors from MRI scans.

Exclusion criteria

• The presence of a cardiac pacemaker or pacemaker wires.
• Metallic particles in the eye.
• Vascular clips in the head or previous neurosurgery.
• Prosthetic heart valves.
• Significant claustrophobia.
• Non-fixed metallic particles (shrapnel).
• Any magnetic metallic particles in the body.
• Failure to assure non-pregnant status.
• Failure to perform the task of lying still.