Transcranial focused ultrasound stimulation with high spatial resolution

Area of Science:

• Neuroscience
• Biomedical Engineering
• Acoustics

Background:

• Low-intensity transcranial focused ultrasound stimulation offers noninvasive brain modulation.
• Current limitations include challenges in achieving high spatial resolution for targeting small animal brain sub-regions, particularly in the axial direction.

Purpose of the Study:

• To develop a dual-crossed transducer system for achieving high axial resolution in ultrasound neuromodulation.
• To enable precise targeting of small brain regions without complex microfabrication or signal processing.

Main Methods:

• Designed a dual-crossed transducer system using two commercially available piezoelectric curved transducers.
• Implemented a fixture to cross the ultrasound beams at their focal lengths.
• Conducted in vivo animal experiments (n=38) to demonstrate target specificity.

Main Results:

• Achieved a full-width at half maximum (FWHM) focal volume under 0.52 μm³.
• Reported a focal diameter of 1 mm in both lateral and axial directions.
• Demonstrated successful in vivo brain stimulation in mice, including targeting the habenula and observing forepaw movement.

Conclusions:

• The dual-crossed transducer system enables highly specific targeting of brain regions using ultrasound stimulation.
• This system is a valuable tool for noninvasive study of complex neurological circuitry.