Guo Xinmeng, Wang Jiang
School of Electrical and Information Engineering, Tianjin University, Tianjin 300072, China.
Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin 300072, China.
Sensors (Basel). 2021 Nov 9;21(22):7432. doi: 10.3390/s21227432.
Acupuncture is one of the oldest traditional medical treatments in Asian countries. However, the scientific explanation regarding the therapeutic effect of acupuncture is still unknown. The much-discussed hypothesis it that acupuncture's effects are mediated via autonomic neural networks; nevertheless, dynamic brain activity involved in the acupuncture response has still not been elicited. In this work, we hypothesized that there exists a lower-dimensional subspace of dynamic brain activity across subjects, underpinning the brain's response to manual acupuncture stimulation. To this end, we employed a variational auto-encoder to probe the latent variables from multichannel EEG signals associated with acupuncture stimulation at the ST36 acupoint. The experimental results demonstrate that manual acupuncture stimuli can reduce the dimensionality of brain activity, which results from the enhancement of oscillatory activity in the delta and alpha frequency bands induced by acupuncture. Moreover, it was found that large-scale brain activity could be constrained within a low-dimensional neural subspace, which is spanned by the "acupuncture mode". In each neural subspace, the steady dynamics of the brain in response to acupuncture stimuli converge to topologically similar elliptic-shaped attractors across different subjects. The attractor morphology is closely related to the frequency of the acupuncture stimulation. These results shed light on probing the large-scale brain response to manual acupuncture stimuli.
针灸是亚洲国家最古老的传统医学疗法之一。然而，关于针灸治疗效果的科学解释仍然未知。备受讨论的假说是针灸的效果是通过自主神经网络介导的；尽管如此，参与针灸反应的动态脑活动仍未被揭示。在这项研究中，我们假设在不同受试者之间存在一个低维的动态脑活动子空间，它支撑着大脑对手动针刺刺激的反应。为此，我们使用变分自编码器从与足三里穴位针刺刺激相关的多通道脑电图信号中探测潜在变量。实验结果表明，手动针刺刺激可以降低脑活动的维度，这是由针刺诱导的δ和α频段振荡活动增强所致。此外，还发现大规模脑活动可以被限制在一个由“针灸模式”所跨越的低维神经子空间内。在每个神经子空间中，不同受试者大脑对针刺刺激的稳定动态反应收敛到拓扑相似的椭圆形吸引子。吸引子形态与针刺刺激的频率密切相关。这些结果为探究大脑对手动针刺刺激的大规模反应提供了线索。
