Department of Information Engineering & Bioengineering and Robotics Research Center E. Piaggio, School of Engineering, University of Pisa, Pisa, Italy.
Department of Applied Neuroscience, Neurons, Inc., Taastrup, Denmark.
Am J Physiol Regul Integr Comp Physiol. 2023 Apr 1;324(4):R513-R525. doi: 10.1152/ajpregu.00251.2022. Epub 2023 Feb 20.
Dynamical information exchange between central and autonomic nervous systems, as referred to functional brain-heart interplay, occurs during emotional and physical arousal. It is well documented that physical and mental stress lead to sympathetic activation. Nevertheless, the role of autonomic inputs in nervous system-wise communication under mental stress is yet unknown. In this study, we estimated the causal and bidirectional neural modulations between electroencephalogram (EEG) oscillations and peripheral sympathetic and parasympathetic activities using a recently proposed computational framework for a functional brain-heart interplay assessment, namely the sympathovagal synthetic data generation model. Mental stress was elicited in 37 healthy volunteers by increasing their cognitive demands throughout three tasks associated with increased stress levels. Stress elicitation induced an increased variability in sympathovagal markers, as well as increased variability in the directional brain-heart interplay. The observed heart-to-brain interplay was primarily from sympathetic activity targeting a wide range of EEG oscillations, whereas variability in the efferent direction seemed mainly related to EEG oscillations in the γ band. These findings extend current knowledge on stress physiology, which mainly referred to top-down neural dynamics. Our results suggest that mental stress may not cause an increase in sympathetic activity exclusively as it initiates a dynamic fluctuation within brain-body networks including bidirectional interactions at a brain-heart level. We conclude that directional brain-heart interplay measurements may provide suitable biomarkers for a quantitative stress assessment and bodily feedback may modulate the perceived stress caused by increased cognitive demand.
中枢神经系统和自主神经系统之间的动态信息交换，即所谓的功能性大脑-心脏相互作用，发生在情绪和身体兴奋时。有充分的文献记载表明，身体和精神压力会导致交感神经激活。然而，自主输入在精神压力下对神经系统内通讯的作用尚不清楚。在这项研究中，我们使用最近提出的用于功能性大脑-心脏相互作用评估的计算框架——交感神经迷走神经综合数据生成模型，估计了脑电图（EEG）振荡与外周交感和副交感活动之间的因果和双向神经调制。通过在三个与压力水平增加相关的任务中增加认知需求，我们在 37 名健康志愿者中诱发了精神压力。压力诱发引起了交感神经标记物变异性的增加，以及大脑-心脏相互作用的变异性增加。观察到的心脏到大脑的相互作用主要来自于针对广泛 EEG 振荡的交感神经活动，而传出方向的变异性似乎主要与 γ 波段的 EEG 振荡有关。这些发现扩展了当前关于应激生理学的知识，应激生理学主要涉及自上而下的神经动力学。我们的结果表明，精神压力可能不会仅导致交感神经活动增加，因为它会在包括大脑-心脏水平双向相互作用的大脑-身体网络内引发动态波动。我们得出结论，定向大脑-心脏相互作用测量可能为定量应激评估提供合适的生物标志物，并且身体反馈可能会调节由于认知需求增加而引起的感知压力。
