Abstract #0533

Deshpande G, LaConte S, Peltier S, Hu X

In this work, we investigated the nonlinear dynamical properties of BOLDresting state fluctuations. EPI data were acquired at 3T in 5 restingsubjects. Patterns of singularity in the complex plane and Lempel-Zivcomplexity were used to study the deterministic nonlinearity in fMRI. Weobserved greater nonlinearity and determinism in gray matter compared to whitematter and CSF. The removal of respiratory and cardiac pulsations decreasedthe nonlinearity and determinism but did not alter the relative differencebetween gray matter and white matter. Therefore, tissue-specific deterministicnonlinearity may reflect native physiological and metabolic fluctuationsrather than physiological artifacts due to respiration and cardiac pulsation.