Directional Connectivity between Frontal and Posterior Brain Regions Is Altered with Increasing Concentrations of Propofol

Anu Maksimow, Minna Silfverhuth, Jaakko Långsjö, Kimmo Kaskinoro, Stefanos Georgiadis, Satu Jääskeläinen, Harry Scheinin, Martin Walter
2014 PLoS ONE  
Recent studies using electroencephalography (EEG) suggest that alteration of coherent activity between the anterior and posterior brain regions might be used as a neurophysiologic correlate of anesthetic-induced unconsciousness. One way to assess causal relationships between brain regions is given by renormalized partial directed coherence (rPDC). Importantly, directional connectivity is evaluated in the frequency domain by taking into account the whole multichannel EEG, as opposed to time
more » ... n or two channel approaches. rPDC was applied here in order to investigate propofol induced changes in causal connectivity between four states of consciousness: awake (AWA), deep sedation (SED), loss (LOC) and return of consciousness (ROC) by gathering full 10/20 system human EEG data in ten healthy male subjects. The target-controlled drug infusion was started at low rate with subsequent gradual stepwise increases at 10 min intervals in order to carefully approach LOC (defined as loss of motor responsiveness to a verbal stimulus). The direction of the causal EEG-network connections clearly changed from AWA to SED and LOC. Propofol induced a decrease (p50.002-0.004) in occipital-to-frontal rPDC of 8-16 Hz EEG activity and an increase (p50.001-0.040) in frontal-to-occipital rPDC of 10-20 Hz activity on both sides of the brain during SED and LOC. In addition, frontal-to-parietal rPDC within 1-12 Hz increased in the left hemisphere at LOC compared to AWA (p50.003). However, no significant changes were detected between the SED and the LOC states. The observed decrease in back-to-front EEG connectivity appears compatible with impaired information flow from the posterior sensory and association cortices to the executive prefrontal OPEN ACCESS Citation: Maksimow A, Silfverhuth M, Långsjö J, Kaskinoro K, Georgiadis S, et al. (2014) Directional Connectivity between Frontal and Posterior Brain Regions Is Altered with Increasing Concentrations of Propofol. PLoS ONE 9(11): e113616.
doi:10.1371/journal.pone.0113616 pmid:25419791 pmcid:PMC4242654 fatcat:wxwjrrszj5apdnu6t3otzjti6a