Neuronal responses to focused ultrasound are gated by pre-stimulation brain rhythms

Abstract

Background: Owing to its high spatial resolution and penetration depth, transcranial focused ultrasound stimulation (tFUS) is one of the most promising approaches to non-invasive neuromodulation. Identifying the impact of endogenous neural activity on neuromodulation outcome is critical to harnessing the potential of tFUS.Objective: Here we sought to identify the relationship between pre-stimulation neural activity and the neuronal response to tFUS. Methods: We applied 3 min of continuous-wave tFUS to the hippocampal region of the rat while recording local field potentials (LFP) and multi-unit activity (MUA) from the target. We also tested the application of tFUS but with an air gap separating the transducer and the skull, as well as active stimulation of the contralateral olfactory bulb. Results: We observed a modest but significant increase in firing rate during hippocampal tFUS, but not during stimulation of the olfactory bulb or when an air gap was present. Importantly, the observed firing rate increase was significantly modulated by the power of baseline oscillations in the LFP, with low levels of delta (1e3 Hz) and high levels of theta (4e10 Hz) and gamma (30e250 Hz) power producing significantly larger firing rate increases. Firing rate increases were also amplified by a factor of 7Â when stimulation was applied during periods of frequent sharp-wave ripple (SWR) activity. Conclusion: Our findings suggest that baseline brain rhythms may effectively "gate" the response to tFUS.

Noninvasive Brain Stimulation Therapies to Promote Recovery of Consciousness: Where We Are and Where We Should Go

“…78 A recent study employing continuous LIFU in the animal model, for example, indicates that the increase in neural firing rates in response to sonication might be modulated by the power of baseline oscillations in local field potential. Specifically, firing rates were maximally increased in the presence of faster baseline oscillations (i.e., high levels of theta and gamma power and low levels of delta power), 79 a profile typically associated with lower levels of impairment in DoC patients. 80…”

Focalização de feixes ultrassônicos provocada pela calota craniana

“…Estudos in vitro forneceram a primeira evidência de que o ultrassom pulsado de baixa intensidade poderia estimular diretamente os potenciais de ação e a transmissão sináptica em circuitos cerebrais (TYLER et al, 2008). O ultrassom focalizado transcraniano (em inglês, transcranial focused ultrasound -tFUS) possui bioefeitos não térmicos (mecânicos) capazes de estimular a atividade de circuitos corticais, talâmicos e hipocampais usado com segurança e eficácia para a neuromodulação cortical em coelhos (YOO et al, 2011b), roedores (KIM et al, 2014KING et al, 2013;LI et al, 2016;MEHIĆ et al, 2014;MOORE et al, 2015;NGUYEN et al, 2022;TUFAIL et al, 2010;YANG et al, 2012), porco (DALLAPIAZZA et al, 2018, ovelhas (LEE et al, 2016a), e revelou modular os comportamentos visomotores em macacos (DEFFIEUX et al, 2013). O tFUS, também, demonstrou ser um método seguro e eficaz de estimulação cortical transitória em humanos (FINI;TYLER, 2017;LEE et al, 2016aLEE et al, , 2016bLEGON et al, 2018a;MUELLER et al, 2014;SANGUINETTI et al, 2020), ver Tabela 1-2.…”