Locating Temporal Functional Dynamics of Visual Short-Term Memory Binding using Graph Modular Dirichlet Energy

Keith Smith, Benjamin Ricaud, Nauman Shahid, Stephen Rhodes, John M. Starr, Augustin Ibáñez, Mario Parra Rodriguez, Javier Escudero, Pierre Vandergheynst

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)
35 Downloads (Pure)


Visual short-term memory binding tasks are a promising early marker for Alzheimer’s disease (AD). To uncover functional
deficits of AD in these tasks it is meaningful to first study unimpaired brain function. Electroencephalogram recordings were
obtained from encoding and maintenance periods of tasks performed by healthy young volunteers. We probe the task’s transient
physiological underpinnings by contrasting shape only (Shape) and shape-colour binding (Bind) conditions, displayed in the left
and right sides of the screen, separately. Particularly, we introduce and implement a novel technique named Modular Dirichlet
Energy (MDE) which allows robust and flexible analysis of the functional network with unprecedented temporal precision. We
find that connectivity in the Bind condition is less integrated with the global network than in the Shape condition in occipital and
frontal modules during the encoding period of the right screen condition. Using MDE we are able to discern driving effects in
the occipital module between 100-140ms, coinciding with the P100 visually evoked potential, followed by a driving effect in
the frontal module between 140-180ms, suggesting that the differences found constitute an information processing difference
between these modules. This provides temporally precise information over a heterogeneous population in promising tasks for
the detection of AD.
Original languageEnglish
Article number42013
JournalScientific Reports
Early online date10 Feb 2017
Publication statusE-pub ahead of print - 10 Feb 2017


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