Expertise-related Global Efficiency of Functional Brain Networks in Professional and New Divers Under Simulated Deep-Water

Although many researchers have been conducted studies on functional brain connectivity (FC), little work has been dedicated to FC in extreme situations. This study aimed at investigating whether the expertise acquired during deep-sea diving is reflected in global efficiency of the functional brain networks in a group of professional divers (PDs) compared with a group of new divers (NDs). The source signals, derived by electroencephalography (EEG) acquisition in a hyperbaric chamber, and the corresponding functional connectivity matrices were extracted in different frequency bands. Examining the overall organization of the brain network using graph analysis, we found a significant decrease of global efficiency in $\alpha$ band in PDs during air breathing and a significant increase of the upper $\beta$ activity during the oxygen breathing and in the post-oxygen air. This provides evidence in support of the hypothesis that the experience and expertise differences would modulate brain networks. These experiments provided the unique opportunity of investigating the impact of the neurophysiological activity in simulated critical scenarios in view of the investigation in real sea-water experiments.