We address the recent controversy over whether focused ultrasound (FUS) activates cortical neurons directly or indirectly by initially activating auditory pathways. We obtained two types of evidence that FUS can directly activate cortical neurons. The depth profile of the local field potential (LFP) in the barrel cortex of the rat in vivo indicated a generator was located within the cortical gray matter. The onset and peak latencies of the initial component p1 were 3.2 ± 0.25 ms (mean ± standard error of the mean) and 7.6 ± 0.12 ms, respectively, for the direct cortical response (DCR), 6.8 ± 0.40 and 14.3 ± 0.54 ms for the FUS-evoked LFP (4 MHz, 3.2 MPa, 50 or 300 µs/pulse, 1–20 pulses at 1 kHz) and 6.9 ± 0.51 and 15.8 ± 0.94 ms for the LFP evoked by 1-ms deflection of the C2 whisker projecting to the same area. The peak latency of the FUS p1 was statistically (t-test) longer than the DCR, but shorter than the whisker p1 at p < 0.005.

我们解决了最近关于聚焦超声 (FUS) 是否通过最初激活听觉通路直接或间接激活皮层神经元的争议。我们获得了两种类型的证据，表明 FUS 可以直接激活皮质神经元。体内大鼠桶状皮层局部场电位（LFP）的深度分布表明发电机位于皮质灰质内。初始成分 p1 的起始和峰值延迟分别为 3.2 ± 0.25 ms（平均值 ± 平均值的标准误差）和 7.6 ± 0.12 ms，对于直接皮质反应 (DCR)，分别为 6.8 ± 0.40 和 14.3 ± 0.54 ms FUS 诱发的 LFP（4 MHz，3.2 MPa，50 或 300 µs/脉冲，1 kHz 下的 1-20 个脉冲）和 6.9 ± 0.51 和 15.8 ± 0.94 ms，由 C2 晶须投影的 1 ms 偏转引起的 LFP到同一个区域。FUS p1 的峰值潜伏期在统计学上（t检验）比 DCR 长，但在p < 0.005 时比须 p1 短。