Abstract：
Objective. Closed-loop transcranial ultrasound stimulation (TUS) can be applied at a specific time according to the state of neural activity to achieve timely and precise neuromodulation and improve the modulation effect. In a previous study, we found that closed-loop TUS at the peaks and troughs of the theta rhythm in the mouse hippocampus was able to increase the absolute power and decrease the relative power of the theta rhythm of local field potentials (LFPs) independent of the peaks and troughs of the stimulus. However, it remained unclear whether the modulation effect of this closed-loop TUS-induced mouse hippocampal neural oscillation depended on the peaks and troughs of the theta rhythm.Approach. In this study, we used ultrasound with different stimulation modes and durations to stimulate the peaks (peak stimulation) and troughs (trough stimulation) of the hippocampal theta rhythm. The LFPs in the area of ultrasound stimulation were recorded and the amplitudes and power spectra of the theta rhythm before and after ultrasound stimulation were analyzed.Main results. The results showed that (a) the relative change in amplitude of theta rhythm decreases as the number of stimulation trials under peak stimulation increases; (b) the relative change in the absolute power of the theta rhythm decreases as the number of stimulation trials under peak stimulation increases; (c) the relative change in amplitude of the theta rhythm increases nonlinearly with the stimulation duration (SD) under peak stimulation, and; (d) the relative change in absolute power exhibits a nonlinear increase with SD under peak stimulation.Significance. These results suggest that the modulation effect of closed-loop TUS on theta rhythm is dependent on the stimulation mode and duration under peak stimulation. TUS has the potential to precisely modulate theta rhythm-related neural activity.
摘要：
Objective.闭环经颅超声刺激（TUS）可以根据神经活动的状态在特定时间施加，以实现及时，精确的神经调制，提高调制效果。在之前的研究中,我们发现,在小鼠海马theta节律的波峰和波谷处的闭环TUS能够增加局部场电位(LFP)的theta节律的绝对功率并降低其相对功率,而与刺激的波峰和波谷无关.然而,目前尚不清楚这种闭环TUS诱导的小鼠海马神经振荡的调节作用是否取决于theta节律的峰和谷。方法。在这项研究中,我们使用不同刺激模式和持续时间的超声来刺激海马theta节律的峰（峰刺激）和谷（谷刺激）。记录超声刺激区域的LFP，并分析超声刺激前后θ节律的幅度和功率谱。主要结果。结果表明:(a)θ节律振幅的相对变化随峰值刺激试验次数的增加而减小;(b)θ节律绝对功率的相对变化随峰值刺激试验次数的增加而减小;(c)θ节律振幅的相对变化随峰值刺激持续时间(SD)呈非线性增加,（d）在峰值刺激下，绝对功率的相对变化随SD呈非线性增加。意义。这些结果表明，闭环TUS对theta节律的调节作用取决于峰值刺激下的刺激模式和持续时间。TUS具有精确调节theta节律相关神经活动的潜力。
