Correlation Between GABA+ Levels In The MPFC Of Young Adults During Light Sleep And Topological Efficiency Of EEG Network Connections

Objective: The aim of our study is to explore the relationship between γ-aminobutyric acid(GABA)levels of medial prefrontal cortex(mPFC)and the topological characters of cerebral EEG functional connectivity network in young adults during light sleep using synchronous electroencephalogram-magnetic resonance spectroscopy(EEG-MRS)scanning technology.Methods: Participants in this study included 37 young adults(right-handed,16 males,21females;age 25(23,26)years,education level,mean = 16.35±1.99 years).Using a 32-channel EEG system to record EEG signals,using Hadamard Encoding and Reconstruction of Mega-Edited Spectroscopy(HERMES)technology and mPFC as the spectral scanning region of interest,synchronous EEG-MRS scanning was used to record the electrical activity of the whole brain and measure the GABA+ level of the medial prefrontal cortex.Using Gannet 3.1 software package to process the MRS data,correcting the brain parenchymal volume according to 3D-TIWI sequence,and then the corrected GABA+level of mPFC was obtained.EEGLAB software was used to preprocess EEG data.Using REAT software to establish the relevant connection matrixes under delta(0.5-4 Hz),theta(4-8 Hz),alpha(8-13 Hz),beta(13-30 Hz)and gamma(above 30 Hz).Then GRETNA software package was used to calculate small world,global efficiency,local efficiency under the five bands during light sleep(N2),applied correlation analysis was to explore the correlation between the topological efficiency of EEG connection networks and the GABA+ level of the medial prefrontal cortex.Results: In this study,the GABA+ level of the medial prefrontal cortex: 0.10(0.07,0.12),was negatively correlated with the global efficiency under theta band(mean = 0.22±0.01)of EEG functional connection network in the N2 phase sleep(r =-0.4520,p = 0.005).The global efficiency of EEG connection network in the rest frequency bands,the local efficiency and small world of EEG connection network in all frequency bands were not correlated with the GABA+ level of mPFC.Conclusion: Our study revealed the correlation between global efficiency of EEG functional connectivity network in theta band and GABA+ levels in medial prefrontal cortex during light sleep.