Neuromodulation of sensory networks in monkey brain by focused ultrasound with MRI guidance and detection

Pai-Feng Yang,Allen T Newton,John C Gore,M Anthony Phipps,Charles F Caskey,Li Min Chen,Vandiver Chaplin

doi:10.1038/s41598-018-26287-7

Pai-Feng Yang, Allen T Newton + Show 5 more

Open Access

https://doi.org/10.1038/s41598-018-26287-7

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Abstract

Focused ultrasound (FUS) has gained recognition as a technique for non-invasive neuromodulation with high spatial precision and the ability to both excite and inhibit neural activity. Here we demonstrate that MRI-guided FUS is capable of exciting precise targets within areas 3a/3b in the monkey brain, causing downstream activations in off-target somatosensory and associated brain regions which are simultaneously detected by functional MRI. The similarity between natural tactile stimulation-and FUS- evoked fMRI activation patterns suggests that FUS likely can excite populations of neurons and produce associated spiking activities that may be subsequently transmitted to other functionally related touch regions. The across-region differences in fMRI signal changes relative to area 3a/3b between tactile and FUS conditions also indicate that FUS modulated the tactile network differently. The significantly faster rising (>1 sec) fMRI signals elicited by direct FUS stimulation at the targeted cortical region suggest that a different neural hemodynamic coupling mechanism may be involved in generating fMRI signals. This is the first demonstration of imaging neural excitation effects of FUS with BOLD fMRI on a specific functional circuit in non-human primates.

Highlights

Regions and circuits within a healthy brain work together in a coordinated fashion; dysfunction in such networks underlie several neurological disorders[1,2,3,4,5,6,7]
We investigated whether long blocks containing Focused ultrasound (FUS) bursts could induce detectable BOLD signals, and how these compared to BOLD effects induced by peripheral cutaneous tactile stimulation
We showed that FUS evoked robust BOLD activations at the target and off-target regions within the touch functional circuit, and that FUS-induced BOLD signal changes are generally similar to those evoked by tactile stimulation, but they can be much stronger and rise faster

Summary

Introduction

Regions and circuits within a healthy brain work together in a coordinated fashion; dysfunction in such networks underlie several neurological disorders[1,2,3,4,5,6,7]. The manipulation of activity within circuits in both positive (excitation) and negative (inhibition) directions, can be a powerful approach to directly correlate changes in neural circuits with functional and behavioral readouts and establish the causal relationships between brain regions. We have developed robust fMRI paradigms that allow us to reliably map brain touch circuits in non-human primates[27,28,29,30,31,32]. We showed that FUS evoked robust BOLD activations at the target and off-target regions within the touch functional circuit, and that FUS-induced BOLD signal changes are generally similar to those evoked by tactile stimulation, but they can be much stronger and rise faster

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