Multi-coil TMS for preclinical applications in ultra-high-field MRI.

Area of Science:

• Neuroscience
• Biomedical Engineering
• Medical Imaging

Background:

• Monitoring brain activity during neuromodulation is crucial for understanding brain function.
• Integrating brain stimulation and imaging techniques presents significant technical challenges, often impacting data quality.

Purpose of the Study:

• To develop and validate a non-invasive brain stimulation system compatible with high-field MRI environments.
• To enable precise, electronically controlled neuromodulation and concurrent neuroimaging in preclinical models.

Main Methods:

• A novel multi-coil transcranial magnetic stimulation (mTMS) system was designed for a 9.4-T MRI scanner.
• The mTMS system allowed for millisecond-level, 1° resolution control of stimulus orientation.
• Concurrent functional magnetic resonance imaging (fMRI) was performed with minimal electromagnetic interference and artifact.

Main Results:

• Orientation-specific cortical stimulation and muscle responses were successfully evoked in anesthetized rats.
• The mTMS system demonstrated minimal interference with MRI magnetic fields (B0 and B1+) and maintained image quality.
• Artifact-free fMRI images were acquired with a short delay (40 ms) between stimulation and imaging.

Conclusions:

• Concurrent electronically targeted brain stimulation and neuroimaging is a feasible and valuable tool for preclinical research.
• This integrated system facilitates the exploration of whole-brain network functions and the development of improved therapeutic strategies.