Novičić Marija, Savić Andrej M
School of Electrical Engineering, University of Belgrade, Bulevar Kralja Aleksandra 73, 11120 Belgrade, Serbia.
Brain Sci. 2023 May 5;13(5):766. doi: 10.3390/brainsci13050766.
Tactile attention tasks are used in the diagnosis and treatment of neurological and sensory processing disorders, while somatosensory event-related potentials (ERP) measured by electroencephalography (EEG) are used as neural correlates of attention processes. Brain-computer interface (BCI) technology provides an opportunity for the training of mental task execution via providing online feedback based on ERP measures. Our recent work introduced a novel electrotactile BCI for sensory training, based on somatosensory ERP; however, no previous studies have addressed specific somatosensory ERP morphological features as measures of sustained endogenous spatial tactile attention in the context of BCI control. Here we show the morphology of somatosensory ERP responses induced by a novel task introduced within our electrotactile BCI platform i.e., the sustained endogenous spatial electrotactile attention task. By applying pulsed electrical stimuli to the two proximal stimulation hotspots at the user's forearm, stimulating sequentially the mixed branches of radial and median nerves with equal probability of stimuli occurrence, we successfully recorded somatosensory ERPs for both stimulation locations, in the attended and unattended conditions. Waveforms of somatosensory ERP responses for both mixed nerve branches showed similar morphology in line with previous reports on somatosensory ERP components obtained by stimulation of exclusively sensory nerves. Moreover, we found statistically significant increases in ERP amplitude on several components, at both stimulation hotspots, while sustained endogenous spatial electrotactile attention task is performed. Our results revealed the existence of general ERP windows of interest and signal features that can be used to detect sustained endogenous tactile attention and classify between spatial attention locations in 11 healthy subjects. The current results show that features of N140, P3a and P3b somatosensory ERP components are the most prominent global markers of sustained spatial electrotactile attention, over all subjects, within our novel electrotactile BCI task/paradigm, and this work proposes the features of those components as markers of sustained endogenous spatial tactile attention in online BCI control. Immediate implications of this work are the possible improvement of online BCI control within our novel electrotactile BCI system, while these finding can be used for other tactile BCI applications in the diagnosis and treatment of neurological disorders by employing mixed nerve somatosensory ERPs and sustained endogenous electrotactile attention task as control paradigms.
触觉注意力任务用于神经和感觉处理障碍的诊断与治疗，而通过脑电图（EEG）测量的体感事件相关电位（ERP）被用作注意力过程的神经关联指标。脑机接口（BCI）技术通过基于ERP测量提供在线反馈，为心理任务执行训练提供了机会。我们最近的工作基于体感ERP引入了一种用于感觉训练的新型电触觉BCI；然而，以前没有研究在BCI控制的背景下将特定的体感ERP形态特征作为持续内源性空间触觉注意力的指标。在这里，我们展示了在我们的电触觉BCI平台内引入的一项新任务（即持续内源性空间电触觉注意力任务）所诱发的体感ERP反应的形态。通过向用户前臂的两个近端刺激热点施加脉冲电刺激，以相等的刺激发生概率依次刺激桡神经和正中神经的混合分支，我们成功记录了在注意和未注意条件下两个刺激位置的体感ERP。两个混合神经分支的体感ERP反应波形显示出与先前关于仅通过感觉神经刺激获得的体感ERP成分的报告一致的相似形态。此外，我们发现，在执行持续内源性空间电触觉注意力任务时，两个刺激热点的几个成分的ERP振幅在统计学上有显著增加。我们的结果揭示了存在可用于检测持续内源性触觉注意力并在11名健康受试者中对空间注意力位置进行分类的一般ERP感兴趣窗口和信号特征。当前结果表明，在我们的新型电触觉BCI任务/范式中，N140、P3a和P3b体感ERP成分的特征是所有受试者中持续空间电触觉注意力最突出的全局标志物，并且这项工作提出将这些成分的特征作为在线BCI控制中持续内源性空间触觉注意力的标志物。这项工作的直接影响是可能改善我们新型电触觉BCI系统中的在线BCI控制，而这些发现可通过采用混合神经体感ERP和持续内源性电触觉注意力任务作为控制范式，用于神经疾病诊断和治疗中的其他触觉BCI应用。
