EEG Synchronizations Length During Meditation


The dynamic structure of the EEG signal is characterized by segments of synchronization and desynchronization. In this paper, the frequency and duration of these segments were monitored during calm meditation and insight meditation in experienced and naive meditators. A newly developed methodology based on complex continuous wavelet coherence was used to estimate these parameters. The durations highly depend on frequency band and vary from 60 ms to 250 ms. A shorter duration and a lower frequency of synchronization were found for experienced meditators during both types of meditations for the real and the imaginary parts of the complex continuous wavelet coherence. The greatest duration differences were in the gamma band, which may be associated with handling attention during meditation, whereas the differences in the alpha band were most significant for frequency. Combining the two parameters resulted in the total duration of the synchronization, which has discriminative accuracy of up to 100% and appears to be a sensitive parameter of the length of training of meditators.

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Continuous wavelet transform


Wavelet cross spectrum


Complex continuous wavelet coherence


Receiver operating characteristic




Finite impulse response


  1. 1.

    Ito, J., Nikolaev, A. R., & van Leeuwen, C. (2005). Spatial and temporal structure of phase synchronization of spontaneous alpha EEG activity. Biological Cybernetics, 92, 54–60.

    Article  MATH  Google Scholar 

  2. 2.

    Gong, P., Nikolaev, A. R., & van Leeuwen, C. (2007). Intermittent dynamics underlying the intrinsic fluctuations of the collective synchronization patterns in electrocortical activity. Physical Review E, 76, 011904.

    Article  Google Scholar 

  3. 3.

    Freeman, W. J. (2007). Proposed cortical “shutter” mechanism in cinematographic perception. In I. Leonid (Ed.), Neurodynamics of cognition and consciousness (pp. 11–38). Berlin: Springer.

    Google Scholar 

  4. 4.

    Thatcher, R. W., Krause, P. J., & Hrybyk, M. (1986). Cortico-cortical associations and EEG coherence: a two-compartmental model. Electroencephalography and Clinical Neurophysiology, 64, 123–143.

    Article  Google Scholar 

  5. 5.

    Rodriguez, E., George, N., Lachaux, J. P., Martinerie, J., Renault, B., & Varela, F. J. (1999). Perception’s shadow: long-distance synchronization of human brain activity. Nature, 397, 430–433.

    Article  Google Scholar 

  6. 6.

    Burkitt, G. R., Silberstein, R. B., Cadusch, P. J., & Wood, A. W. (2000). Steady-state visual evoked potentials and travelling waves. Clinical Neurophysiology, 111, 246–258.

    Article  Google Scholar 

  7. 7.

    Varela, F., Lachaux, J. P., Rodriguez, E., & Martinerie, J. (2001). The brainweb: phase synchronisation and large-scale integration. Nature Reviews Neurosciences, 2, 228–239.

    Article  Google Scholar 

  8. 8.

    Netoff, T. I., & Schiff, S. J. (2002). Decreased neuronal synchronization during experimental seizures. Journal of Neuroscience, 22, 7297–7307.

    Google Scholar 

  9. 9.

    Gupta, D., & James, C.J. (2007). Narrowband vs. broadband phase synchronization analysis applied to independent components of ictal and interictal EEG. In Engineering in Medicine and Biology Society (pp. 3864–3867). Lyon: IEEE

  10. 10.

    Ying, J., Zhou, D., Lin, K., & Gao, X. (2015). Network analysis of functional brain connectivity driven by gamma-band auditory steady-state response in auditory hallucinations. Journal of Medical and Biological Engineering, 35, 45–51.

    Article  Google Scholar 

  11. 11.

    Al-Subari, K., Al-Baddai, S., Tomé, A. M., Volberg, G., Hammwöhner, R., & Lang, E. W. (2015). Ensemble empirical mode decomposition analysis of EEG data collected during a Contour integration task. PLoS ONE, 10(4), e0119489.

    Article  Google Scholar 

  12. 12.

    Tanaka, K., Mizuno, Y., Tanaka, T., & Kitajo, K. (2013). Detection of phase synchronization in EEG with bivariate empirical mode decomposition. In 35th Annual International Conference of the IEEE Engineering in Medicine and Biology (vol. 213, pp. 973–976).

  13. 13.

    Räsänen, O., Metsäranta, M., & Vanhatalo, S. (2013). Development of a novel robust measure for interhemispheric synchrony in the neonatal EEG: activation synchrony index (ASI). Neuroimage, 69, 256–266.

    Article  Google Scholar 

  14. 14.

    Nolte, G., Bai, O., Wheaton, L., Mari, Z., Vorbach, S., & Hallett, M. (2004). Identifying true brain interaction from EEG data using the imaginary part of coherency. Clinical Neurophysiology, 115, 2292–2307.

    Article  Google Scholar 

  15. 15.

    Pantev, C., Makeig, S., Hoke, M., Galambos, R., Hampson, S., & Gallen, C. (1991). Human auditory evoked gamma-band magnetic fields. Proceedings of the National Academy of Sciences USA, 88, 8996–9000.

    Article  Google Scholar 

  16. 16.

    Tiitinen, H., Sinkkonen, J., Reinikainen, K., Alho, K., Lavikainen, J., & Näätänen, R. (1993). Selective attention enhances the auditory 40-Hz transient response in humans. Nature, 364, 59–60.

    Article  Google Scholar 

  17. 17.

    Strüber, D., Basar-Eroglu, C., Hoff, E., & Stadler, M. (2000). Reversal-rate dependent differences in the EEG gamma-band during multistable visual perception. International Journal of Psychophysiology, 38, 243–252.

    Article  Google Scholar 

  18. 18.

    Basar, E., Basar-Eroglu, C., Karakas, S., & Schurmann, M. (2001). Gamma, alpha, delta, and theta oscillations govern cognitive processes. International Journal of Psychophysiology, 39, 241–248.

    Article  Google Scholar 

  19. 19.

    Keil, A., Müller, M. M., Gruber, T., Wienbruch, C., & Elbert, T. (2001). Human large-scale oscillatory brain activity during an operant shaping procedure. Cognitive Brain Research, 12, 397–407.

    Article  Google Scholar 

  20. 20.

    Freeman, W. J., & Rogers, L. J. (2002). Fine temporal resolution of analytic phase reveals episodic synchronization by state transitions in gamma EEGs. Journal of Neurophysiology, 87, 937–945.

    Google Scholar 

  21. 21.

    Baer, R. A. (2005). Mindfulness-based treatment approaches: clinician’s guide to evidence base and applications. London: Academic Press.

    Google Scholar 

  22. 22.

    Didonna, F. (2009). Clinicall hanbook of mindfulness. New York: Springer.

    Google Scholar 

  23. 23.

    Tang, Y. Y., & Posner, M. I. (2013). Tools of the trade: theory and method in mindfulness neuroscience. Social Cognive and Affective Neuroscience, 8, 118–120.

    Article  Google Scholar 

  24. 24.

    Ahani, A., Wahbeh, H., Nezamfar, H., Miller, M., Erdogmus, D., & Oken, B. (2014). Quantitative change of EEG and respiration signals during mindfulness meditation. Journal of Neuroengineering and Rehabilitation, 11, 1–11.

    Article  Google Scholar 

  25. 25.

    Cahn, B. R., & Polich, J. (2006). Meditation states and traits: EEG, ERP, and neuroimaging studies. Psychological Bulletin, 132, 180–211.

    Article  Google Scholar 

  26. 26.

    Lutz, A., Slagter, H. A., Dunne, J. D., & Davidson, R. J. (2008). Attention regulation and monitoring in meditation. Trends in Cognitive Science, 12, 163–169.

    Article  Google Scholar 

  27. 27.

    Lutz, A., Greischar, L. L., Rawlings, N. B., Ricard, M., & Davidson, R. J. (2004). Long-term meditators self-induce high-amplitude gamma synchrony during mental practice. Proceedings of the National Academy of Sciences USA, 16, 16369–16373.

    Article  Google Scholar 

  28. 28.

    Cahn, B. R., Delorme, A., & Polich, J. (2010). Occipital gamma activation during Vipassana meditation. Cognitive Processing, 11, 39–56.

    Article  Google Scholar 

  29. 29.

    Engell, A. D., & McCarthy, G. (2010). Selective attention modulates face-specific induced gamma oscillations recorded from ventral occipitotemporal cortex. Journal of Neuroscience, 30, 8780–8786.

    Article  Google Scholar 

  30. 30.

    Jensen, O., Kaiser, J., & Lachaux, J. P. (2007). Human gamma-frequency oscillations associated with attention and memory. Trends in Neuroscience, 30, 317–324.

    Article  Google Scholar 

  31. 31.

    Cahn, B. R., Delorme, A., & Polich, J. (2013). Event-related delta, theta, alpha and gamma correlates to auditory oddball processing during Vipassana meditation. Social Cognitive and Affective Neuroscience, 8, 100–111.

    Article  Google Scholar 

  32. 32.

    Fries, P., Nikolic, D., & Singer, W. (2007). The gamma cycle. Trends. Neuroscience, 30, 309–316.

    Google Scholar 

  33. 33.

    Duncan, N. W., Wiebking, C., & Northoff, G. (2014). Associations of regional GABA and glutamate with intrinsic and extrinsic neural activity in humans-A review of multimodal imaging studies. Neuroscience and Biobehavioral Reviews, 47, 36–52.

    Article  Google Scholar 

  34. 34.

    Womelsdorf, T., Fries, P., Mitra, P. P., & Desimone, R. (2006). Gamma-band synchronization in visual cortex predicts speed of change detection. Nature, 439, 733–736.

    Article  Google Scholar 

  35. 35.

    Steinmetz, P. N., Roy, A., Fitzgerald, P. J., Hsiao, S. S., Johnson, K. O., & Niebur, E. (2000). Attention modulates synchronized neuronal firing in primate somatosensory cortex. Nature, 404, 187–190.

    Article  Google Scholar 

  36. 36.

    Taylor, K., Mandon, S., Freiwald, W. A., & Kreiter, A. K. (2005). Coherent oscillatory activity in monkey area V4 predicts successful allocation of attention. Cerebral Cortex, 15, 1424–1437.

    Article  Google Scholar 

  37. 37.

    Torrence, C., & Compo, G.P. (1998). A practical guide to wavelet analysis. Bulletin of the American. Meteorological Society, 79, 61–78.

  38. 38.

    Shnibha, R., & Albarbar, A. (2013). Petroleum Pumps’ current and vibration signatures analysis using wavelet coherence technique. Advances in Acoustics and Vibration, 6.

  39. 39.

    Grinsted, A., Moore, J. C., & Jevrejeva, S. (2004). Application of the cross wavelet transform and wavelet coherence to geophysical time series. Nonlinear Processes in Geophysics, 11, 561–566.

    Article  Google Scholar 

  40. 40.

    Walker, J.S. (2008). A primer on wavelets and their scientific applications. New York: CRC Press

  41. 41.

    Buzsáki, G., & Draguhn, A. (2004). Neuronal oscillations in cortical networks. Science, 304, 1926–1929.

    Article  Google Scholar 

  42. 42.

    Chung, D., Yun, K., & Jeong, J. (2015). Decoding covert motivations of free riding and cooperation from multi-feature pattern analysis of EEG signals. Social Cognitive and Affective Neuroscience, 10(9), 1210–1218.

  43. 43.

    Kopal, J., Vyšata, O., Burian, J., Schätz, M., Procházka, A., & Vališ, M. (2014). Complex continuous wavelet coherence for EEG microstates detection in insight and calm meditation. Consciousness and Cognition, 30, 13–23.

    Article  Google Scholar 

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This work was supported by the grant MH CZ- DRO. Faculty Hospital in Hradec Kralove (long-term organization development plan) (UHHK, 00179906) and by the grant PRVOUK: P37/08.

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Correspondence to Jakub Kopal.

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The authors declare that they have no competing interests.

Authors’ contributions

JK, OV, AP participated in the design of the study and performed the statistical analysis. Data were collected and analyzed by the investigators JK, JB, OV. OV, AP, MV conceived of the study, and participated in its design and helped to draft the manuscript. All authors read and approved the final manuscript.

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Kopal, J., Vyšata, O., Burian, J. et al. EEG Synchronizations Length During Meditation. J. Med. Biol. Eng. 37, 220–229 (2017).

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  • Calm meditation
  • Continuous complex wavelet coherence
  • EEG synchronization
  • Insight meditation