Manipulation of Subcortical and Deep Cortical Activity in the Primate Brain Using Transcranial Focused Ultrasound Stimulation

Summary

The causal role of an area within a neural network can be determined by interfering with its activity and measuring the impact. Many current reversible manipulation techniques have limitations preventing their application, particularly in deep areas of the primate brain. Here, we demonstrate that a focused transcranial ultrasound stimulation (TUS) protocol impacts activity even in deep brain areas: a subcortical brain structure, the amygdala (experiment 1), and a deep cortical region, the anterior cingulate cortex (ACC, experiment 2), in macaques. TUS neuromodulatory effects were measured by examining relationships between activity in each area and the rest of the brain using functional magnetic resonance imaging (fMRI). In control conditions without sonication, activity in a given area is related to activity in interconnected regions, but such relationships are reduced after sonication, specifically for the targeted areas. Dissociable and focal effects on neural activity could not be explained by auditory confounds.

Highlights

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  Ultrasound stimulation exerts regionally specific neural effects in primates

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  It can be used to alter activity even in subcortical and deep cortical areas

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  After stimulation, activity in a brain area is less related to that of its network

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  The effect lasted for more than 1 h and was not mediated by auditory confounds

Abstract

Ultrasound can be used to modulate activity in deep brain areas. After stimulation, activity in the targeted brain area becomes less coupled to its network. Effects are specific to the stimulation site, long-lasting, and not due to auditory confounds.