Neuromodulatory Responses Elicited by Intermittent versus Continuous Transcranial Focused Ultrasound Stimulation of...

Area of Science:

• Neuroscience
• Biomedical Engineering
• Neuromodulation

Background:

• Transcranial focused ultrasound stimulation (tFUS) is a neuromodulation technique.
• tFUS can induce plasticity like long-term potentiation (LTP) or depression (LTD).
• Variability in tFUS effects may stem from stimulation patterns (intermittent vs. continuous).

Purpose of the Study:

• To evaluate the neuromodulatory effects of intermittent and continuous tFUS on motor cortical plasticity.
• To compare the impact of different tFUS stimulation patterns on neural biomarkers.
• To assess the safety of tFUS in a rodent model.

Main Methods:

• Developed a platform for intermittent and continuous tFUS application in rats.
• Measured motor cortical excitability using motor-evoked potentials (MEPs) via transcranial magnetic stimulation (TMS).
• Analyzed c-Fos and GAD-65 expression via immunohistochemistry; assessed GFAP for safety.

Main Results:

• Intermittent tFUS facilitated motor excitability; continuous tFUS inhibited it.
• Intermittent tFUS increased c-Fos and decreased GAD-65 expression.
• Continuous tFUS decreased c-Fos and increased GAD-65 expression.
• Neither tFUS pattern induced observable injury (GFAP analysis).

Conclusions:

• Both intermittent and continuous tFUS effectively modulate cortical excitability.
• Different tFUS patterns yield distinct neuromodulatory effects.
• tFUS interventions are safe and well-tolerated, with potential for clinical applications.