BACKGROUND Transcranial focused ultrasound (tFUS) is a noninvasive brain stimulation method that may modulate deep brain structures. This study investigates whether sonication of the right anterior thalamus would modulate thermal pain thresholds in healthy individuals. METHODS We enrolled 19 healthy individuals in this three-visit, double-blind, sham-controlled, crossover trial. Participants first underwent a structural MRI scan used solely for tFUS targeting. They then attended two identical experimental tFUS visits (counterbalanced by condition) at least one week apart. Within the MRI scanner, participants received two, 10-minute sessions of either active or sham tFUS spread 10 minutes apart targeting the right anterior thalamus [fundamental frequency: 650kHz, Pulse repetition frequency: 10 Hz, Pulse Width: 5ms, Duty Cycle: 5%, Sonication Duration: 30s, Inter-Sonication Interval: 30 s, Number of Sonications: 10, ISPTA.0 995 mW/cm2, ISPTA.3 719 mW/cm2, Peak rarefactional pressure 0.72 MPa]. The primary outcome measure was quantitative sensory thresholding (QST), measuring sensory, pain, and tolerance thresholds to a thermal stimulus applied to the left forearm before and after right anterior thalamic tFUS. RESULTS The right anterior thalamus was accurately sonicated in 17 of the 19 subjects. Thermal pain sensitivity was significantly attenuated after active tFUS. The pre-post x active-sham interaction was significant (F(1,245.95)=4.03, p=.046). This interaction indicates that in the sham stimulation condition, thermal pain thresholds decreased 1.08ºC (SE=.28) pre-post session, but only decreased .51ºC (SE=.30) pre-post session in the active stimulation group. CONCLUSIONS Two 10-minute sessions of anterior thalamic tFUS induces antinociceptive effects in healthy individuals. Future studies should optimize the parameter space, dose and duration of this effect which may lead to multi-session tFUS interventions for pain disorders.

中文翻译：

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使用 MRI 引导的经颅聚焦超声 (tFUS) 超声处理前丘脑改变健康成人的疼痛阈值：一项双盲、假对照研究

背景经颅聚焦超声（tFUS）是一种无创的脑刺激方法，可以调节脑深部结构。这项研究调查了右前丘脑的超声处理是否会调节健康个体的热痛阈值。方法 我们在这项三访视、双盲、假对照、交叉试验中招募了 19 名健康个体。参与者首先接受了仅用于 tFUS 靶向的结构 MRI 扫描。然后，他们至少相隔一周参加了两次相同的实验性 tFUS 访问（由条件抵消）。在 MRI 扫描仪中，参与者接受了两次 10 分钟的主动或假 tFUS 会话，间隔 10 分钟，针对右前丘脑 [基本频率：650kHz，脉冲重复频率：10Hz，脉冲宽度：5ms，占空比：5 %, 超声处理持续时间：30 秒，超声处理间隔：30 秒，超声处理次数：10，ISPTA.0 995 mW/cm2，ISPTA.3 719 mW/cm2，峰值稀疏压力 0.72 MPa]。主要结果测量是定量感觉阈值 (QST)，测量在右前丘脑 tFUS 之前和之后应用于左前臂的热刺激的感觉、疼痛和耐受阈值。结果 19 名受试者中有 17 名的右前丘脑被准确地超声处理。主动 tFUS 后热痛敏感性显着减弱。前后 x 主动假交互是显着的 (F(1,245.95)=4.03, p=.046)。这种相互作用表明，在假刺激条件下，热痛阈值在训练前降低了 1.08ºC (SE=.28)，但在主动刺激组中仅降低了 0.51ºC (SE=.30)。结论 两次 10 分钟的丘脑前部 tFUS 治疗可在健康个体中诱导镇痛作用。未来的研究应该优化这种效应的参数空间、剂量和持续时间，这可能会导致疼痛障碍的多会话 tFUS 干预。