Cortical Brain Connectivity Evaluated by Graph Theory in Dementia: A Correlation Study between Functional and Structural Data

Fabrizio Vecchio, Francesca Miraglia, Giuseppe Curcio, Riccardo Altavilla, Federica Scrascia, Federica Giambattistelli, Carlo Cosimo Quattrocchi, Placido Bramanti, Fabrizio Vernieri, Paolo Maria Rossini

Research output: Contribution to journalArticlepeer-review


A relatively new approach to brain function in neuroscience is the "functional connectivity", namely the synchrony in time of activity in anatomically-distinct but functionally-collaborating brain regions. On the other hand, diffusion tensor imaging (DTI) is a recently developed magnetic resonance imaging (MRI)-based technique with the capability to detect brain structural connection with fractional anisotropy (FA) identification. FA decrease has been observed in the corpus callosum of subjects with Alzheimer's disease (AD) and mild cognitive impairment (MCI, an AD prodromal stage). Corpus callosum splenium DTI abnormalities are thought to be associated with functional disconnections among cortical areas. This study aimed to investigate possible correlations between structural damage, measured by MRI-DTI, and functional abnormalities of brain integration, measured by characteristic path length detected in resting state EEG source activity (40 participants: 9 healthy controls, 10 MCI, 10 mild AD, 11 moderate AD). For each subject, undirected and weighted brain network was built to evaluate graph core measures. eLORETA lagged linear connectivity values were used as weight of the edges of the network. Results showed that callosal FA reduction is associated to a loss of brain interhemispheric functional connectivity characterized by increased delta and decreased alpha path length. These findings suggest that "global" (average network shortest path length representing an index of how efficient is the information transfer between two parts of the network) functional measure can reflect the reduction of fiber connecting the two hemispheres as revealed by DTI analysis and also anticipate in time this structural loss.

Original languageEnglish
Pages (from-to)745-756
Number of pages12
JournalJournal of Alzheimer's Disease
Issue number3
Publication statusPublished - 2015


  • Alzheimer's disease
  • delta and alpha bands
  • diffusion tensor imaging
  • EEG
  • functional connectivity
  • graph theory
  • mild cognitive impairment

ASJC Scopus subject areas

  • Psychiatry and Mental health
  • Geriatrics and Gerontology
  • Clinical Psychology
  • Medicine(all)

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