Currently, blindness cannot be cured and patients’ living quality can be compromised severely. Ultrasonic (US) neuromodulation is a promising technology for the development of noninvasive cortical visual prosthesis. We investigated the feasibility of transcranial focused ultrasound (tFUS) for noninvasive stimulation of the visual cortex (VC) to develop improved visual prosthesis. tFUS was used to successfully evoke neural activities in the VC of both normal and retinal degenerate (RD) blind rats. Our results showed that blind rats showed more robust responses to ultrasound stimulation when compared with normal rats. ( ${p} < {0.001}$ , two-sample t-test). Three different types of ultrasound waveforms were used in the three experimental groups. Different types of cortical activities were observed when different US waveforms were used. In all rats, when stimulated with continuous ultrasound waves, only short-duration responses were observed at “US on and off” time points. In comparison, pulsed waves (PWs) evoked longer low-frequency responses. Testing different parameters of PWs showed that a pulse repetition frequency higher than 100 Hz is required to obtain the low-frequency responses. Based on the observed cortical activities, we inferred that acoustic radiation force (ARF) is the predominant physical mechanism of ultrasound neuromodulation.

中文翻译：

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经颅聚焦超声对视觉皮层的非侵入性神经调节

目前，盲目症无法治愈，患者的生活质量可能受到严重损害。超声（US）神经调节是开发无创皮层视觉假体的有前途的技术。我们调查了经颅聚焦超声（tFUS）的无创性刺激视觉皮层（VC）的可行性，以开发改进的视觉假体。tFUS用于成功诱发正常和视网膜变性（RD）盲鼠VC的神经活动。我们的结果表明，与正常大鼠相比，盲大鼠对超声刺激表现出更强的反应。（ $ {p} <{0.001} $ ，两次样本t检验）。在三个实验组中使用了三种不同类型的超声波形。当使用不同的美国波形时，观察到不同类型的皮质活动。在所有大鼠中，当用连续超声波刺激时，在“ US on and off”时间点仅观察到短期响应。相比之下，脉冲波（PW）引起了更长的低频响应。测试PW的不同参数表明，要获得低频响应，需要高于100 Hz的脉冲重复频率。基于观察到的皮层活动，我们推断声辐射力（ARF）是超声神经调节的主要物理机制。