Yoo Seung-Schik, Yoon Kyungho, Croce Phillip, Cammalleri Amanda, Margolin Ryan W, Lee Wonhye
Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA.
Int J Imaging Syst Technol. 2018 Jun;28(2):106-112. doi: 10.1002/ima.22262. Epub 2017 Dec 15.
Low-intensity transcranial focused ultrasound (FUS) has emerged as a non-invasive brain stimulation modality that can reach deep brain areas with high spatial specificity. Previous studies have identified transient effects of FUS on the brain excitability and accompanying physiological responses. Yet the presence of long-lasting effects of FUS, which extend on the order of half an hour or more, has not been probed. We transcranially applied FUS to the somatosensory areas of the anesthetized rats for 10 min at a low duty cycle (5%) and intensity, far below the level that could alter the tissue temperature. Concurrently, we measured electroencephalographic (EEG) somatosensory evoked potentials (SEP) induced by the unilateral electrical stimulation of the hind limb before and after the sonication. Compared to the control sham condition that did not involve sonication, differential SEP features were evident and persisted beyond 35 min after the administration of FUS. The presence of this non-transient neuromodulatory effect may provide early evidence that FUS-mediated brain stimulation has the potential to induce neuroplasticity.
低强度经颅聚焦超声（FUS）已成为一种非侵入性脑刺激方式，能够以高空间特异性到达脑深部区域。以往研究已确定FUS对脑兴奋性及伴随的生理反应具有短暂影响。然而，FUS持续半小时或更长时间的长期影响尚未得到探究。我们以低占空比（5%）和强度，在远低于可改变组织温度的水平下，经颅对麻醉大鼠的体感区施加FUS 10分钟。同时，我们在超声处理前后测量了单侧后肢电刺激诱发的脑电图（EEG）体感诱发电位（SEP）。与未进行超声处理的对照假手术条件相比，差异SEP特征明显，且在给予FUS后35分钟以上持续存在。这种非短暂性神经调节作用的存在可能提供早期证据，表明FUS介导的脑刺激有诱导神经可塑性的潜力。
