School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, China.
State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an, China.
Sci Rep. 2018 Apr 11;8(1):5835. doi: 10.1038/s41598-018-24008-8.
Visual evoked potential-based brain-computer interfaces (BCIs) have been widely investigated because of their easy system configuration and high information transfer rate (ITR). However, the uncomfortable flicker or brightness modulation of existing methods restricts the practical interactivity of BCI applications. In our study, a flicker-free steady-state motion visual evoked potential (FF-SSMVEP)-based BCI was proposed. Ring-shaped motion checkerboard patterns with oscillating expansion and contraction motions were presented by a high-refresh-rate display for visual stimuli, and the brightness of the stimuli was kept constant. Compared with SSVEPs, few harmonic responses were elicited by FF-SSMVEPs, and the frequency energy of SSMVEPs was concentrative. These FF-SSMVEPs evoked "single fundamental peak" responses after signal processing without harmonic and subharmonic peaks. More stimulation frequencies could thus be selected to elicit more responding fundamental peaks without overlap with harmonic peaks. A 40-target online SSMVEP-based BCI system was achieved that provided an ITR up to 1.52 bits per second (91.2 bits/min), and user training was not required to use this system. This study also demonstrated that the FF-SSMVEP-based BCI system has low contrast and low visual fatigue, offering a better alternative to conventional SSVEP-based BCIs.
基于视觉诱发电位的脑-机接口（BCI）因其系统配置简单、信息传输率（ITR）高而得到广泛研究。然而，现有的方法存在闪烁或亮度调制的不舒适问题，限制了 BCI 应用的实际交互性。在我们的研究中，提出了一种无闪烁稳态运动视觉诱发电位（FF-SSMVEP）的 BCI。采用高刷新率显示器呈现具有振荡扩展和收缩运动的环形运动棋盘格图案作为视觉刺激，且刺激的亮度保持不变。与 SSVEPs 相比，FF-SSMVEP 诱发的谐波响应较少，SSMVEP 的频率能量集中。经过信号处理后，FF-SSMVEP 可产生“单一基本峰”响应，而没有谐波和次谐波峰。因此，可以选择更多的刺激频率来诱发更多的响应基本峰，而不会与谐波峰重叠。实现了一个 40 目标的在线 SSMVEP 脑-机接口系统，其 ITR 高达 1.52 位/秒（91.2 位/分钟），并且不需要用户进行训练即可使用该系统。本研究还表明，基于 FF-SSMVEP 的 BCI 系统对比度低、视觉疲劳低，是传统 SSVEP 脑-机接口的更好替代方案。
