MohammadMehdi Kafashan1, Ben Julian A Palanca2, ShiNung Ching3. 1. Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA; Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA. 2. Department of Anesthesiology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA; Division of Biology and Biomedical Sciences, Washington University in St. Louis, St. Louis, MO 63130, USA. 3. Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA; Division of Biology and Biomedical Sciences, Washington University in St. Louis, St. Louis, MO 63130, USA. Electronic address: shinung@ese.wustl.edu.
Abstract
BACKGROUND: Resting wakefulness is not a unitary state, with evidence accumulating that spontaneous reorganization of brain activity can be assayed through functional magnetic resonance imaging (fMRI). The dynamics of correlated fMRI signals among functionally-related brain regions, termed dynamic functional connectivity (dFC), may represent nonstationarity arising from underlying neural processes. However, given the dimensionality and noise inherent in such recordings, seeming fluctuations in dFC could be due to sampling variability or artifacts. NEW METHOD: Here, we highlight key methodological considerations when evaluating dFC in resting-state fMRI data. COMPARISON WITH EXISTING METHOD: In particular, we demonstrate how dimensionality reduction of fMRI data, a common practice often involving principal component analysis, may give rise to spurious dFC phenomenology due to its effect of decorrelating the underlying time-series. CONCLUSION: We formalize a dFC assessment that avoids dimensionality reduction and use it to show the existence of at least two FC states in the resting-state.
BACKGROUND: Resting wakefulness is not a unitary state, with evidence accumulating that spontaneous reorganization of brain activity can be assayed through functional magnetic resonance imaging (fMRI). The dynamics of correlated fMRI signals among functionally-related brain regions, termed dynamic functional connectivity (dFC), may represent nonstationarity arising from underlying neural processes. However, given the dimensionality and noise inherent in such recordings, seeming fluctuations in dFC could be due to sampling variability or artifacts. NEW METHOD: Here, we highlight key methodological considerations when evaluating dFC in resting-state fMRI data. COMPARISON WITH EXISTING METHOD: In particular, we demonstrate how dimensionality reduction of fMRI data, a common practice often involving principal component analysis, may give rise to spurious dFC phenomenology due to its effect of decorrelating the underlying time-series. CONCLUSION: We formalize a dFC assessment that avoids dimensionality reduction and use it to show the existence of at least two FC states in the resting-state.
Authors: C J Honey; O Sporns; L Cammoun; X Gigandet; J P Thiran; R Meuli; P Hagmann Journal: Proc Natl Acad Sci U S A Date: 2009-02-02 Impact factor: 11.205
Authors: Ben Julian A Palanca; Anish Mitra; Linda Larson-Prior; Abraham Z Snyder; Michael S Avidan; Marcus E Raichle Journal: Anesthesiology Date: 2015-08 Impact factor: 7.892