Kozhevnikov Maria, Irene Strasser Alina Veronika, McDougal Elizabeth, Dhond Rupali, Samuel Geoffrey
National University of Singapore, Psychology Department, Singapore.
Martinos Center for Biomedical Imaging, MGH & Harvard Medical School, MA, USA.
Curr Res Neurobiol. 2022 Sep 30;3:100053. doi: 10.1016/j.crneur.2022.100053. eCollection 2022.
Here we report meditative techniques, which modulate attentional control by arousal-driven influences and not by monitoring continuous thought processes as during mindfulness-related practices. We focus on Vajrayana (Tantric Buddhism) practices, during which a sequence of generation (self-visualization as a deity - Yidam) or completion with sign (inner heat -Tummo) stages necessarily precedes non-dual awareness (NDA) Tantric Mahamudra. We compared the electrocardiographic and electroencephalographic correlates of Mahamudra performed after rest (non-Tantric Mahamudra) with Mahamudra performed after Yidam (Tantric Mahamudra) in 16 highly experienced Vajrayana practitioners, 10 of whom also performed Tummo. Both Yidam and Tummo developed the state of PNS withdrawal (arousal) and phasic alertness, as reflected by HF HRV decreases and Alpha2 power increases, later neurophysiologically employed in Tantric Mahamudra. The latter led to the unique state of high cortical excitability, "non-selective" focused attention, and significantly reduced attentional control, quantified by power reductions in all frequency bands, except Theta. In contrast, similar to mindfulness-related practices, non-Tantric Mahamudra was performed in a state of PNS dominance (relaxation), tonic alertness, and active monitoring, as suggested by Alpha1 power increases and less pronounced decreases in other frequency bands. A neurobiological model of meditation is proposed, differentiating arousal-based and mindfulness-related practices.
在此，我们报告冥想技巧，这些技巧通过唤醒驱动的影响来调节注意力控制，而不是像正念相关练习那样通过监测连续的思维过程。我们专注于金刚乘（密宗佛教）的修行，在此过程中，一系列生起次第（将自己观想为神灵——本尊）或圆满次第（内在热——拙火）阶段必然先于非二元觉知（NDA）密宗大手印。我们比较了16位经验丰富的金刚乘修行者在休息后进行的大手印（非密宗大手印）与在观想本尊后进行的大手印（密宗大手印）的心电图和脑电图相关性，其中10人还进行了拙火修行。观想本尊和拙火修行都产生了副交感神经系统撤离（唤醒）和相位警觉状态，这通过高频心率变异性降低和α2功率增加得以体现，这些在之后的密宗大手中被神经生理学地应用。后者导致了高皮质兴奋性、“非选择性”集中注意力的独特状态，以及注意力控制显著降低，这通过除θ波外所有频段的功率降低来量化。相比之下，与正念相关练习类似，非密宗大手印是在副交感神经系统主导（放松）、紧张性警觉和主动监测的状态下进行的，这由α1功率增加以及其他频段不太明显的降低所表明。我们提出了一个冥想的神经生物学模型，区分基于唤醒的练习和与正念相关的练习。
