Characterization of in vivo neuronal and inter-neuronal responses to transcranial focused ultrasound

非侵入性神经调节方法已经被开发出来，使神经组织的调节不需要侵入性外科手术。低强度经颅聚焦超声（tFUS）神经调节已经证明了其从神经元到回路水平调节大脑的有效性和准确性。然而，迫切需要阐明tFUS神经调节在体内神经元和神经元间的作用，从而推进tFUS神经调节在人体上的转化应用。我们建议使用一种新型的128元随机超声阵列，系统地检测麻醉和清醒大鼠模型的tFUS参数，以研究tFUS的体内神经元细胞类型特异性反应和长期可塑性效应。提出的实验研究是建立在我们的初步探索和严格理解不同的低强度tFUS参数如何导致独特的体内神经元群体之间的不平等反应以及麻醉啮齿动物模型中使用颅内记录的突触连通性的持续改变的基础上。具体目标如下：目的1。在麻醉大鼠模型上，体感觉皮层回路对tFUS刺激的内在体内细胞型特异性反应的表征。我们将在体内麻醉大鼠模型中使用多通道电生理记录来表征体感觉皮层回路中对tFUS刺激的细胞类型特异性神经反应。我们将通过细胞类型特异性光遗传大鼠模型进一步提高我们的询问精度。目标2。清醒头固定大鼠tFUS内在体内细胞类型特异性的研究。清醒头部固定模型不受麻醉作用的抑制，是研究tFUS神经调节对不同细胞类型时空激活以及清醒大脑局部神经网络间脑活动传播的理想模型。目标3。频率特异性调节tFUS诱导麻醉和清醒头固定大鼠的可塑性。我们将系统地研究tFUS刺激对突触连通性的长期影响。我们将验证以下假设：1)tFUS刺激能够编码频率特异性信息，诱导海马持续突触可塑性；2)tFUS刺激参数的模式对变化程度有显著影响。该研究的成功完成有望通过研究体内细胞类型对超声刺激在体感觉皮层的特异性反应以及海马和体感觉皮层的长期效应的诱导来揭示tFUS的体内细胞机制。我们将系统地表征、建模、验证和了解体内神经元和神经元间对tFUS刺激的反应，不仅推动神经调节疗法向临床应用的转化，而且进一步了解健康大脑中的特定神经回路。

Non-invasive neuromodulation approaches have been developed to enable the modulation of neural tissue without necessitating invasive surgical procedures. Low-intensity transcranial focused ultrasound (tFUS) neuromodulation has proven its efficacy and precision in modulating the brain, from the neuron to circuit level. However, there is an urgent unmet need to elucidate the in vivo neuronal and inter-neuronal effects of the tFUS neuromodulation, thus advancing the translational application of tFUS neuromodulation on humans. We propose to investigate the in vivo neuronal cell-type specific response and long-term plasticity effects of tFUS by systematically examining tFUS parameters in both anesthetized and awake rat models using a novel, cutting-edge 128-element random ultrasound array for rodents. The proposed experimental investigations are built upon our preliminary explorations and rigorous understanding of how different low-intensity tFUS parameters lead to unequal responses among unique in vivo neuron populations and the sustained alteration of synaptic connectivity in anesthetized rodent models using intracranial recordings. We will address the following specific aims. Aim 1. Characterization of intrinsic in vivo cell-type specific response of somatosensory cortical circuits to tFUS stimulation on anesthetized rat models. We will characterize the cell-type specific neural responses to tFUS stimulation in somatosensory cortical circuits using multi-channel electrophysiological recordings in an in vivo anesthetized rat model. We will further increase the precision of our interrogations through cell-type specific optogenetic rat models. Aim 2. Investigation of intrinsic in vivo cell-type specificity of tFUS in awake head-fixed rats. Uninhibited by anesthesia effects, the awake head fixed model is ideal for the investigation of tFUS neuromodulation on the spatial and temporal activation of different cell types, as well as the propagation of brain activities across local neural networks in the awake brain. Aim 3. Frequency specific modulation of tFUS to induce plasticity in anesthetized and awake head-fixed rats. We will systematically study the long-term effects of tFUS stimulation on synaptic connectivity. We will test the hypotheses that 1) tFUS stimulation is able to encode frequency specific information inducing sustained synaptic plasticity in the hippocampus, and 2) the pattern of the tFUS stimulation parameters has a significant effect on the degree of change. The successful completion of the proposed research promises to uncover the in vivo cellular mechanism of tFUS by investigating in vivo cell- type specific responses to ultrasound stimulation at somatosensory cortex and the induction of long-term effects at both the hippocampus and somatosensory cortex. We will systematically characterize, model, validate and understand the in vivo neuronal and inter-neuronal responses to tFUS stimulation, not only to propel the translation of neuromodulation therapies to clinical utility but also further the understanding of the specific neural circuits in healthy brains.