State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai, People's Republic of China.
J Neural Eng. 2020 Aug 14;17(4):046041. doi: 10.1088/1741-2552/aba55f.
We used EEG to investigate cortical oscillatory activities during the tactile discrimination task and characterize the correlation between the EEG features and subjects' discrimination performance.
Transcutaneous electrical nerve stimulation (TENS) was applied on two finger areas (thumb and index for healthy hands, thumb and index-projected areas for disabled hands) to evoke two kinds of tactile sensations (vibration and pressure) with three levels of intensities (low, medium and high). Four forearm amputees and thirteen able-bodied subjects were recruited to discriminate the specific intensity and area of the applied stimulation. We assessed the discrimination performance [discrimination accuracy rate (AR) and response time (RT)] to quantify the tactile acuity. During the stimulation, EEG signals were recorded and the evoked cortical oscillatory activities were analyzed. Linear regression analyses were performed between EEG features and tactile discrimination performance.
Spectral analysis revealed that alpha ERD over somatosensory regions persisted the whole task period and was related to the sensory information processing. Alpha ERD over prefrontal regions was only found during the stimulation judgement period and might reflect advanced cognitive process. There was no linear correlation between prefrontal alpha ERD and tactile discrimination performance. While contralateral somatosensory alpha ERDs exhibited significantly negative correlations with ARs ([Formula: see text]) and positive correlations with RTs ([Formula: see text]). Specifically, the fitting results of higher alpha band (10-13 Hz) were superior to lower alpha band (8-10 Hz).
Alpha ERD over contralateral somatosensory cortex could be used as an objective index for the evaluation of tactile acuity and might have the potential to be applied in sensory rehabilitation for amputees.
我们使用 EEG 研究触觉辨别任务期间的皮质振荡活动，并描述 EEG 特征与受试者辨别性能之间的相关性。
经皮神经电刺激（TENS）施加于两个手指区域（健康手的拇指和食指，残疾手的拇指和食指投影区域），以三种强度（低、中、高）诱发两种触觉感觉（振动和压力）。招募了四名前臂截肢者和 13 名健全受试者来辨别应用刺激的特定强度和区域。我们评估了辨别性能（辨别准确率（AR）和反应时间（RT））以量化触觉敏锐度。在刺激期间，记录 EEG 信号并分析诱发的皮质振荡活动。在 EEG 特征和触觉辨别性能之间进行线性回归分析。
频谱分析表明，感觉区域的 alpha 去同步（ERD）持续整个任务期间，与感觉信息处理有关。前额叶区域的 alpha ERD 仅在刺激判断期间发现，可能反映了高级认知过程。前额叶 alpha ERD 与触觉辨别性能之间没有线性相关性。而对侧感觉 alpha ERD 与 ARs 呈显著负相关（[公式：见正文]），与 RTs 呈正相关（[公式：见正文]）。具体而言，较高 alpha 频段（10-13 Hz）的拟合结果优于较低 alpha 频段（8-10 Hz）。
对侧感觉皮质的 alpha ERD 可作为触觉敏锐度评估的客观指标，有可能应用于截肢者的感觉康复。
