Graph theoretical analysis of functional brain networks during Alzheimer´s disease

In this study, the functional magnetic resonance imaging data from Alzheimer´s patients and nondemented older adults are investigated using graph theory. Voxel-based graphs were built on the data obtained from an international data center and their clustering coefficients and characteristic path lengths were calculated. No significant differences were found between the two groups in these two parameters. Afterwards, the voxels acting as hubs and their corresponding brain regions were determined. Some differences were observed with respect to the hub locations. These results point to the fact that rather than a change in the global organization of the brain, Alzheimer´s disease causes a functional change in some brain regions.