Bidirectional and state-dependent modulation of brain activity by transcranial focused ultrasound in non-human primates

• Published in: Brain stimulation Vol. 14; no. 2; pp. 261 - 272
• Main Authors: Yang, Pai-Feng, Phipps, M. Anthony, Jonathan, Sumeeth, Newton, Allen T., Byun, Nellie, Gore, John C., Grissom, William A., Caskey, Charles F., Chen, Li Min
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-03-2021; Elsevier
• Subjects: Animals; Brain - diagnostic imaging; Brain circuit; Brain Mapping; Female; fMRI; Hand; Humans; Magnetic Resonance Imaging; Neuromodulation; Primates; Rest; Somatosensory; Transcranial focused ultrasound; TES; FUS; MCC; Neuromodulation; Hand; ROI; Ins; Somatosensory; fMRI; Transcranial focused ultrasound; VPL; DBS; Primates; ICS; BOLD; MR-ARFI; TMS; Brain circuit; HRF; S2
• ISSN: 1935-861X; 1876-4754
• DOI: 10.1016/j.brs.2021.01.006

Transcranial focused ultrasound (FUS) stimulation under MRI guidance, coupled with functional MRI (fMRI) monitoring of effects, offers a precise, noninvasive technology to dissect functional brain circuits and to modulate altered brain functional networks in neurological and psychiatric disorders. Here we show that ultrasound at moderate intensities modulated neural activity bi-directionally. Concurrent sonication of somatosensory areas 3a/3b with 250 kHz FUS suppressed the fMRI signals produced there by peripheral tactile stimulation, while at the same time eliciting fMRI activation at inter-connected, off-target brain regions. Direct FUS stimulation of the cortex resulted in different degrees of BOLD signal changes across all five off-target regions, indicating that its modulatory effects on active and resting neurons differed. This is the first demonstration of the dual suppressive and excitative modulations of FUS on a specific functional circuit and of ability of concurrent FUS and MRI to evaluate causal interactions between functional circuits with neuron-class selectivity.
•Ultrasound at moderate intensities modulate neural activity bi-directionally.•It suppresses tactile activation at the target while exciting off-target regions.•It’s modulatory effects on active and resting neurons differed.•It likely acts differently on different types of neurons and specific functional circuits.