Mesoscopic Behavior in Biological and Physical Systems, August 28-September 4, 2006, Budapest, Hungary
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Large-Scale Cortical Oscillatory Network Graphs Steven L. Bressler Center of Complex Systems and Brain Sciences Florida Atlantic University Abstract The mammalian cerebral cortex has a highly complex pattern of large-scale anatomical connectivity. This anatomical structure provides a huge combinatorial space of possible functional arrangements of distributed neuronal assemblies. My colleagues and I have developed an approach to the analysis of cortical functional activity that reveals an oscillatory network structure that coordinates distributed assemblies in relation to specific cognitive microstates. This analytic approach involves the use of power spectra to identify distributed cortical assemblies generating oscillatory activity in specific frequency ranges. These assemblies represent nodes of large-scale network graphs. Significantly synchronized assemblies are then identified using spectral coherence analysis. Pairs of synchronized assemblies represent edges of large-scale network graphs. Finally, significant directed causal influences are identified using spectral Granger causality analysis. The causal relations between assembly pairs represent directed edges of large-scale graphs. Our analytic approach has made possible new insights into the functional organization of the cerebral cortex in relation to specific cognitive functions. |
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