Parameter optimisation for mitigating somatosensory confounds during transcranial ultrasonic stimulation

Area of Science:

• Neuroscience
• Biophysics
• Biomedical Engineering

Background:

• Transcranial Ultrasonic Stimulation (TUS) offers precise, non-invasive neuromodulation.
• Peripheral confounds, particularly somatosensory, are overlooked challenges in TUS.
• Increasing TUS intensity and device compactness necessitate managing these confounds.

Purpose of the Study:

• Systematically characterize somatosensory co-stimulation during TUS.
• Identify parameters to effectively mitigate TUS-induced somatosensory confounds.
• Map the confound-parameter space for optimized TUS protocols.

Main Methods:

• Investigated dose-response effects, pulse shaping, and transducer parameters.
• Systematically mapped somatosensory confound across various TUS parameters.
• Analyzed particle displacement (strain) as a potential biophysical driver.

Main Results:

• Somatosensory confounds are reduced by avoiding scalp intensity peaks and spreading ultrasound energy.
• Longer, lower-intensity pulses are more effective than shorter, higher-intensity pulses.
• Higher pulse repetition frequencies and fundamental frequencies decrease somatosensory effects.

Conclusions:

• Actionable strategies are provided to minimize somatosensory confounds in TUS.
• Optimized TUS parameters enhance experimental control and reliability.
• Findings support the advancement of TUS for scientific and clinical applications.