Miniaturized optically-generated Bessel beam ultrasound for volumetric transcranial brain stimulation

TL;DR

This paper introduces a miniaturized optically-generated Bessel beam ultrasound device that enables precise, volumetric, and transcranial brain stimulation, overcoming current limitations in size, resolution, and tissue penetration.

Contribution

The study presents a novel 2.33 mm device capable of volumetric brain stimulation with improved transcranial efficiency and resolution, advancing non-invasive neuromodulation techniques.

Findings

Achieves 152 um lateral and 1.93 mm axial resolution

Stimulates cells at 2.2 mm depth in mouse brain slices

Outperforms conventional ultrasound in transcranial transmission

Abstract

Non-invasive stimulation of small, variably shaped brain sub-regions is crucial for advancing our understanding of brain functions. Current ultrasound neuromodulation faces two significant trade-offs when targeting brain sub-regions: miniaturization versus volumetric control and spatial resolution versus transcranial capability. Here, we present an optically-generated Bessel beam ultrasound (OBUS) device designed to overcome these limitations. This 2.33 mm-diameter miniaturized device delivers a column-shaped field achieving a lateral resolution of 152 um and an axial resolution of 1.93 mm, targeting brain sub-regions with an elongated volume of tissue activation. Immunofluorescence imaging of mouse brain slices confirms its ability to stimulate cells at a depth of 2.2 mm. Additionally, OBUS outperforms conventional Gaussian ultrasound in transcranial transmission efficiency and beam shape preservation. Electrophysiological recordings and functional MRI captured rodent brain responses evoked by OBUS, demonstrating OBUS's ability to non-invasively activate neural circuits in intact brains. This technology offers new possibilities for studying brain functions with precision and volumetric control.