Analysis of Meditation vs. Sensory Engaged Brain States Using Shannon Entropy and Pearson’s First Skewness Coefficient Extracted from EEG Data

Abstract

It has been proposed that meditative states show different brain dynamics than other more engaged states. It is known that when people sit with closed eyes instead of open eyes, they have different brain dynamics, which may be associated with a combination of deprived sensory input and more relaxed inner psychophysiological and cognitive states. Here, we study such states based on a previously established experimental methodology, with the aid of an electro-encephalography (EEG) array with 128 electrodes. We derived the Shannon Entropy (H) and Pearson’s 1st Skewness Coefficient (PSk) from the power spectrum for the modalities of meditation and video watching, including 20 participants, 11 meditators and 9 non-meditators. The discriminating performance of the indices H and PSk was evaluated using Student’s t-test. The results demonstrate a statistically significant difference between the mean H and PSk values during meditation and video watch modes. We show that the H index is useful to discriminate between Meditator and Non-Meditator participants during meditation over both the prefrontal and occipital areas, while the PSk index is useful to discriminate Meditators from Non-Meditators based on the prefrontal areas for both meditation and video modes. Moreover, we observe episodes of anti-correlation between the prefrontal and occipital areas during meditation, while there is no evidence for such anticorrelation periods during video watching. We outline directions of future studies incorporating further statistical indices for the characterization of brain states.

Information-Theoretical Analysis of the Cycle of Creation of Knowledge and Meaning in Brains under Multiple Cognitive Modalities

“…Experiments were conducted using Electrical Geodesics Inc (EGI, Eugene, OR, USA) 128-channel scalp EEG electrode arrays [ 44 ], following the basic methodology for experimental design and data acquisition described in [ 36 ] with 20 participants. Expanding on the previous results using only 2 modalities (meditation and video watching) with 20 participants, here we describe the outcomes corresponding to 6 modalities:…”

“…Amongst the participants were eleven (11) meditators varying in expertise and nine (9) non-meditators. The present work excludes the analysis of the significance of meditation experience among the participants; for meditation-related results, see [ 36 ]. Here we group meditation and relaxation in the modality MED as described above.…”

“…In order to fill in the open positions in the matrix, some of the data channels were duplicated. Two locations on the prefrontal cortex, A(12,3) and A(12,10), were used as reference positions and left open; see [ 36 ] for experimental details.…”

“…The challenges are daunting, as the extraction of meaning from scalp EEG signals appears to be intractable due to, for example, the drastic deterioration of the brain electric signals after passing through the skull, amongst other challenges. Nonetheless, a breakthrough in this problem is possible, based on advanced signal processing and information-theoretical analysis [ 34 , 35 , 36 ].…”

“…Next, we present EEG experiments based on human participants in different modalities, collected in Ian J. Kirk’s Lab, Centre for Brain Research at The University of Auckland in New Zealand [ 42 , 43 ]. Previously, we reported results of EEG measurements with two modalities, meditation and video watching [ 36 ], which are now extended to six modalities [ 37 ], including meditation, scrambled words, video watching, ambiguous images, math mind, and sentences, for a comprehensive and robust analysis. We apply mathematical and statistical analysis using pragmatic information indices to evaluate the EEG experimental data.…”