State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China.
State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China; IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China; Center for Collaboration and Innovation in Brain and Learning Sciences, Beijing Normal University, Beijing, China.
Neuroimage. 2020 Apr 15;210:116550. doi: 10.1016/j.neuroimage.2020.116550. Epub 2020 Jan 22.
Transcranial brain mapping techniques, such as functional near-infrared spectroscopy (fNIRS) and transcranial magnetic stimulation (TMS), have been playing an increasingly important role in studies of human brain functions. Given a brain function of interest, fNIRS probes and TMS coils should be properly placed on the scalp to ensure that the function is effectively measured or modulated. However, since brain activity is inside the skull and invisible to the researcher during placement, this blind targeting may cause the device to partially or completely miss the functional target, resulting in inconsistent experimental results and divergent clinical outcomes, especially when participants' structural MRI data are not available. To address this issue, we propose here a framework for targeting a designated function directly from the scalp. First, a functional brain atlas for the targeted brain function is constructed via a meta-analysis of large-scale functional magnetic resonance imaging datasets. Second, the functional brain atlas is presented on the scalp surface by using a transcranial mapping previously established from an structural MRI dataset (n = 114), resulting in a novel functional transcranial brain atlas (fTBA). Finally, a low-cost, portable scalp-navigation system is used to localize the transcranial device on the individual's scalp with the guidance of the fTBA. To demonstrate the feasibility of the targeting framework, both fNIRS and TMS mapping experiments were conducted. The results show that fTBA-guided fNIRS positioning can detect functional activity with high sensitivity and specificity for working memory and motor systems; Moreover, compared with traditional TMS targeting approaches (e.g. the International 10-20 System and the conventional 5-cm rule), the fTBA suggested motor stimulation site is closesr to both the motor hotspot and the center of gravity of motor evoked potentials (MEP-COG). In summary, the proposed method unblinds the transcranial function targeting process using prior information, providing an effective and straightforward approach to transcranial brain mapping studies, especially those without participants' structural MRI data.
经颅脑映射技术，如功能近红外光谱（fNIRS）和经颅磁刺激（TMS），在人类大脑功能研究中发挥着越来越重要的作用。给定感兴趣的大脑功能，应将 fNIRS 探头和 TMS 线圈正确放置在头皮上，以确保有效地测量或调节功能。然而，由于大脑活动在头骨内部，在放置过程中对研究人员不可见，这种盲目靶向可能导致设备部分或完全错过功能目标，导致实验结果不一致和临床结果分歧，尤其是当参与者的结构 MRI 数据不可用时。为了解决这个问题，我们在这里提出了一种从头皮直接靶向指定功能的框架。首先，通过对大规模功能磁共振成像数据集的元分析构建靶向大脑功能的功能脑图谱。其次，通过使用先前从结构 MRI 数据集（n = 114）建立的经颅映射在头皮表面呈现功能脑图谱，从而产生新的功能经颅脑图谱（fTBA）。最后，使用低成本、便携式头皮导航系统在 fTBA 的指导下将经颅设备定位在个体的头皮上。为了证明靶向框架的可行性，进行了 fNIRS 和 TMS 映射实验。结果表明，fTBA 引导的 fNIRS 定位可以以高灵敏度和特异性检测工作记忆和运动系统的功能活动；此外，与传统的 TMS 靶向方法（例如国际 10-20 系统和传统的 5 厘米规则）相比，fTBA 建议的运动刺激部位更接近运动热点和运动诱发电位（MEP-COG）的重心。总之，该方法使用先验信息使经颅功能靶向过程不受限制，为经颅脑映射研究提供了一种有效且直接的方法，特别是对于没有参与者结构 MRI 数据的研究。
