16This study examines the short-term effects of focused-attention meditation on 17 functional brain state in novice meditators. There are a number of feature metrics 18 for functional brain states, such as functional connectivity, graph theoretical 19 metrics, and amplitude of low frequency fluctuation (ALFF). It is necessary to 20 choose appropriate metrics and also to specify the region of interests (ROIs) 21 from a number of brain regions. Here, we use a Tucker3 clustering method, 22 which simultaneously selects the feature vectors (graph theoretical metrics and 23 fractional ALFF) and the ROIs that can discriminate between resting and 24 meditative states based on the characteristics of the given data. In this study, 25 breath-counting meditation, one of the most popular forms of focused-attention 26 meditation, was used and brain activities during resting and meditation states 27 were measured by functional magnetic resonance imaging. The results indicated 28 that the clustering coefficients of eight brain regions tended to increase through 29 the meditation. Our results reveal that short-term effects of breath-counting 30 meditation can be explained by network density changes in these eight brain 31 regions.
33Mindfulness meditation is said to be influential in physicality, cognition, and 34 mentality, and also has positive effects on well-being [1, 2]. Mindfulness-based 35 stress reduction (MBSR) [3] and mindfulness-based cognitive therapy (MBCT) [4] 36 are clinical interventions based on mindfulness meditation, and it has been 37 reported that these interventions alleviate symptoms of disorders, such as anxiety 38 disorders [5, 6], depression [7], and substance use disorders [8]. Furthermore, it 39 has also been reported that the practice of meditation contributes to improvement 40 of well-being, quality of life [1, 2], immune function [9, 10], and cognitive function 41 [11][12][13][14], not only for unhealthy people but also for healthy ones. 42 On the other hand, the biological mechanisms of mindfulness meditation 43 have also been studied. In particular, the neural basis of mindfulness meditation 44 has been investigated using noninvasive neuroimaging methods such as elec-45 troencephalography (EEG) [15, 16] and functional magnetic resonance imaging 46 (fMRI) [17, 18]. 47 For example, Short et al. have reported that expert meditators showed higher 48 activation in the anterior cingulate cortex (ACC) and dorsolateral prefrontal 49 cortex (dlPFC) during meditation [19], indicating that long-term practice of 50 meditation affects brain function through effects on neuroplasticity. Hasenkamp 51 et al. have revealed that there were four cognitive states during meditation: 52 FOCUS (representing maintenance of attentional focus on the breath), MW 53 (representing mind wandering or loss of focus), AWARE (representing the aware-54ness of mind wandering), and SHIFT (representing shifting of focus back to the 55 breath). They also found that the different brain regions were activated ...
