Abstract
Scopolamine administration may be considered as a psychopharmacological model of Alzheimer’s disease (AD). Here, we studied a group of healthy elderly under scopolamine to test whether it elicits similar changes in brain connectivity as those observed in AD, thereby verifying a possible model of AD impairment. We did it by testing healthy elderly subjects in two experimental conditions: glycopyrrolate (placebo) and scopolamine administration. We then analyzed magnetoencephalographic (MEG) data corresponding to both conditions in resting-state with eyes closed. This analysis was performed in source space by combining a nonlinear frequency band-specific measure of functional connectivity (phase locking value, PLV) with network analysis methods. Under scopolamine, functional connectivity between several brain areas was significantly reduced as compared to placebo, in most frequency bands analyzed. Besides, regarding the two complex network indices studied (clustering and shortest path length), clustering significantly decreased in the alpha band while shortest path length significantly increased also in alpha band both after scopolamine administration. Overall our findings indicate that both PLV and graph analysis are suitable tools to measure brain connectivity changes induced by scopolamine, which causes alterations in brain connectivity apparently similar to those reported in AD.
Highlights
Scopolamine administration may be considered as a psychopharmacological model of Alzheimer’s disease (AD)
We have investigated here whether functional brain networks were impaired after the administration of a cholinergic receptor antagonist in healthy elderly subjects
We evaluated whether the effects of scopolamine on Functional Connectivity (FC) and functional MEG network structure mirrored the disconnection syndrome reported in Alzheimer’s Disease (AD) patients[5,28,29]
Summary
Scopolamine administration may be considered as a psychopharmacological model of Alzheimer’s disease (AD). We analyzed magnetoencephalographic (MEG) data corresponding to both conditions in resting-state with eyes closed This analysis was performed in source space by combining a nonlinear frequency band-specific measure of functional connectivity (phase locking value, PLV) with network analysis methods. We re-analyzed here the whole data set (using all MEG channels available: 122) by combining graph theory with a nonlinear index of phase synchronization, the PLV, to study FC in the source space, between 88 brain regions, in 5 frequency bands. We hypothesize that functional MEG connectivity in source space will decrease after scopolamine administration as compared to placebo, and that the architecture of the functional brain network, assessed by graph theory analysis, will resemble that observed in ADs patients. The current study will provide evidences of a model of AD and of the usefulness of FC analysis in the study and description of brain networks
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
