Song Xizi, Su Xiuli, Chen Xinrui, Xu Minpeng, Ming Dong
IEEE Trans Neural Syst Rehabil Eng. 2022;30:2233-2241. doi: 10.1109/TNSRE.2022.3196828. Epub 2022 Aug 11.
Based on the acoustoelectric (AE) effect, transcranial acoustoelectric brain imaging (tABI) is of potential for brain functional imaging with high temporal and spatial resolution. With nonlinear and non-steady-state, brain electrical signal is microvolt level which makes the development of tABI more difficult. This study demonstrates for the first time in vivo tABI of different steady-state visual stimulation paradigms.
To obtain different brain activation maps, we designed three steady-state visual stimulation paradigms, including binocular, left eye and right eye stimulations. Then, tABI was implemented with one fixed recording electrode. And, based on decoded signal power spectrum (tABI-power) and correlation coefficient between steady-state visual evoked potential (SSVEP) and decoded signal (tABI-cc) respectively, two imaging methods were investigated. To quantitatively evaluate tABI spatial resolution performance, ECoG was implemented at the same time. Finally, we explored the performance of tABI transient imaging.
Decoded AE signal of activation region is consistent with SSVEP in both time and frequency domains, while that of the nonactivated region is noise. Besides, with transcranial measurement, tABI has a millimeter-level spatial resolution (< 3mm). Meanwhile, it can achieve millisecond-level (125ms) transient brain activity imaging.
Experiment results validate tABI can realize brain functional imaging under complex paradigms and is expected to develop into a brain functional imaging method with high spatiotemporal resolution.
基于声电（AE）效应，经颅声电脑成像（tABI）在脑功能成像方面具有高时空分辨率的潜力。由于脑电信号具有非线性和非稳态性，其幅值处于微伏级，这使得tABI的发展更加困难。本研究首次在体内实现了不同稳态视觉刺激范式下的tABI。
为了获得不同的脑激活图，我们设计了三种稳态视觉刺激范式，包括双眼、左眼和右眼刺激。然后，使用一个固定的记录电极进行tABI。并且，分别基于解码信号功率谱（tABI-power）以及稳态视觉诱发电位（SSVEP）与解码信号之间的相关系数（tABI-cc），研究了两种成像方法。为了定量评估tABI的空间分辨率性能，同时进行了皮层脑电图（ECoG）检查。最后，我们探索了tABI瞬态成像的性能。
激活区域的解码声电信号在时域和频域上均与SSVEP一致，而非激活区域的解码声电信号则为噪声。此外，通过经颅测量，tABI具有毫米级的空间分辨率（<3mm）。同时，它能够实现毫秒级（125ms）的脑瞬态活动成像。
实验结果验证了tABI能够在复杂范式下实现脑功能成像，并有望发展成为一种具有高时空分辨率的脑功能成像方法。
