Cognitive Processing

, Volume 19, Issue 4, pp 527–536 | Cite as

Topographical assessment of neurocortical connectivity by using directed transfer function and partial directed coherence during meditation

  • Laxmi ShawEmail author
  • Aurobinda Routray
Research Report


Due to the presence of nonlinearity and volume conduction in electroencephalography (EEG), sometimes it’s challenging to find out the actual brain network from neurodynamical alteration. In this paper, two well-known time–frequency brain connectivity measures, namely partial directed coherence (PDC) and directed transfer function (DTF), have been applied to evaluate the performance analysis of EEG signals obtained during meditation. These measures are implemented to the multichannel meditation EEG data to get the directed neural information flow. Mostly the assessment of PDC and DTF is entirely subjective and there are probabilities to have erroneous connectivity estimation. To avoid the subjective evaluation, the performance results are compared in terms of absolute energy, signal-to-noise ratio (SNR) and relative SNR (R-SNR) scale. In most of the cases, the PDC result is found to be more efficient than DTF. The limitation of DTF and PDC in terms of the time-varying multivariate autoregressive (MVAR) model is highlighted. The time-varying MVAR model can track the neurodynamical changes better than any other method. In the present study, we would like to show that the PDC-based connectivity gives a better understanding of the non-symmetric relation in EEG obtained during Kriya Yoga meditation in comparison to DTF. However, it needs to be investigated further to warrant this claim.


EEG Partial directed coherence Multivariate autoregressive model Volume conduction Meditation Brain connectivity 



This research was supported by MHRD funded grant ‘CEH-Sandhi’ at Indian Institute of Technology, Kharagpur. We thank all the subjects from Hariharananda Gurukulam Ashram, the holy city of Puri, in Odisha, India, for their participation. We would also like to thank the research team for their help and cooperation.

Compliance with ethical standards

Conflict of interest

The authors declare no conflict of interest.


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Copyright information

© Marta Olivetti Belardinelli and Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Electrical EngineeringIndian Institute of Technology KharagpurKharagpurIndia

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