Investigating the effects of sub-anesthetic nitrous oxide exposure on EEG features
Chukwu, Emmanuel Chimezie (2023)
Chukwu, Emmanuel Chimezie
2023
Bioteknologian ja biolääketieteen tekniikan maisteriohjelma - Master's Programme in Biotechnology and Biomedical Engineering
Lääketieteen ja terveysteknologian tiedekunta - Faculty of Medicine and Health Technology
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Hyväksymispäivämäärä
2023-05-08
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202303032741
https://urn.fi/URN:NBN:fi:tuni-202303032741
Tiivistelmä
The human brain has one of the most complex networks in the world. Neuroscience attempts to address this complexity by studying the function of the regular nervous system and the effects of neurological, neurodevelopmental, and psychiatric disorders. Major depressive disorder is a known clinical condition plaguing millions today. Some research seeks to give insight into the mechanisms and therapeutic processes of clinical depression. There has been some evidence that nitrous oxide relieves depression symptoms in some subjects, but little is known about how nitrous gas affects brain interactions after anaesthesia. In this work, continuous and intermittent EEG data of subjects induced with the gas were pre-processed to remove prevalent noise and separated into even window trials according to a pipeline. It was possible to evaluate the effects of the circumstances on brain connections since the weight phase lag index had the greater statistical power to identify phase synchronization alterations and was least sensitive to additional noise sources that are uncorrelated. Graph analysis of EEG data shows that nitrous oxide alters brain connectivity on a varied scale. The strength of these changes differs among the subjects and frequency bands considered, but all subjects' neural interactions were consistently altered by nitrous oxide. The effects of nitrous oxide on the EEG were evident in both groups, with some participants exhibiting increased delta connectivity values. After anaesthesia, a noticeable decline in beta band connection strength was observed in individuals in the continuous group. Small data size, sensor-level data and lack of preceding research are potential limitations of this work. With more participants, data points and source-level data analysis, a more comprehensive understanding of nitrous oxide's effect on the brain may be possible. This thesis does not, therefore, make any general assertions about the use of nitrous oxide as an antidepressant. However, the methods developed in this work will be beneficial in further study of this investigation.