The use of DCEEG to estimate functional and metabolic state of nervous tissue of the brain at hyper- and hypoventilation

Sergey Murik

doi:10.1038/npre.2011.6638.1

Abstract

AbstractA pilot study has been made of the simultaneous DC potential and total slow electrical activity changes during modeling various metabolic and functional states of the human brain. The multi-electrode DCEEG recordings have been performed during the hyperventilation (frequent deep one-minute long breathing motions) and the hypoventilation (voluntary breath holding). It has been shown that the ischemic state occurring in hyperventilation is accompanied by the negative shift of DC potential and increase in the EEG rhythms amplitude. A distention of brain vessels during hypoventilation (voluntary breath-hold) and an improvement of blood supply and thus improvement of vital and functional state of neurons gave rise to an increase in the EEG rhythm amplitude too, though against a background of a positive DC-potential shift. Obtained results are considered in context of the generation of the qualitatively different functional states of brain cells during hyper- and hypoventilation which is reflected in their resting potential and activity. The conducted study shows the prospects for DCEEG and the method we used for DCEEG data processing to understand the character of functional and metabolic changes in the nervous tissue.

Highlights

In the first half of the last decade, there appeared a number of publications [1-2] considering full-band EEG as a promising method that could succeed the classical EEG
Hyperventilation is considered as a model of weak ischemia [29]
We have found some individual characteristics of the character of direct current EEG (DCEEG) change during hyperventilation

Summary

Introduction

In the first half of the last decade, there appeared a number of publications [1-2] considering full-band EEG (fbEEG) as a promising method that could succeed the classical EEG. In the early 21 century some publications [18-19] appeared concerning one of the old ideas [20] about the possibility of non-neuronal origin of the DC potential This idea implies that the DC potential recorded from the brain surface and the scalp is the potential difference occurring at the boundary between the arterial and venous circulatory systems, determined by ion gradients between arterial and venous blood and interstitial fluid accumulated in brain ventricles. The authors reported that the rise or fall of these gases in blood cause the DC potential shift They consider this relationship a direct indication for the non-neuronal nature of the DC potential. The fact that the change in concentration of these gases and vascular responses may cause changes in metabolism in the neurons and shifts in polarization of their membrane is neither considered nor studied experimentally by the authors. We suppose that the number of arguments supplied for non-neuronal origin of the DC potential is insufficient to deny the arguments and facts obtained over many decades by tens of investigators in the support of the neuronal nature of this potential

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Conclusion