Modulation of steady state functional connectivity in the default mode and working memory networks by cognitive load

Interregional correlations between blood oxygen level dependent (BOLD) magnetic resonance imaging (fMRI) signals in the resting state have been interpreted as measures of connectivity across the brain. Here we investigate whether such connectivity in the working memory and default mode networks is modulated by changes in cognitive load. Functional connectivity was measured in a steady‐state verbal identity N‐back task for three different conditions (N = 1, 2, and 3) as well as in the resting state. We found that as cognitive load increases, the functional connectivity within both the working memory the default mode network increases. To test whether functional connectivity between the working memory and the default mode networks changed, we constructed maps of functional connectivity to the working memory network as a whole and found that increasingly negative correlations emerged in a dorsal region of the posterior cingulate cortex. These results provide further evidence that low frequency fluctuations in BOLD signals reflect variations in neural activity and suggests interaction between the default mode network and other cognitive networks. Hum Brain Mapp, 2010. © 2010 Wiley‐Liss, Inc.

[1]  B. Biswal,et al.  Functional connectivity in the motor cortex of resting human brain using echo‐planar mri , 1995, Magnetic resonance in medicine.

[2]  Maurizio Corbetta,et al.  The human brain is intrinsically organized into dynamic, anticorrelated functional networks. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[3]  M. Lowe,et al.  Functional Connectivity in Single and Multislice Echoplanar Imaging Using Resting-State Fluctuations , 1998, NeuroImage.

[4]  H. Swadlow,et al.  Neuronal responses in rabbit cingulate cortex linked to quick-phase eye movements during nystagmus. , 1988, Journal of Neurophysiology.

[5]  P. Fransson.  Spontaneous low‐frequency BOLD signal fluctuations: An fMRI investigation of the resting‐state default mode of brain function hypothesis , 2005, Human brain mapping.

[6]  Catie Chang,et al.  Effects of model-based physiological noise correction on default mode network anti-correlations and correlations , 2009, NeuroImage.

[7]  M. Fukunaga,et al.  Low frequency BOLD fluctuations during resting wakefulness and light sleep: A simultaneous EEG‐fMRI study , 2008, Human brain mapping.

[8]  Rory A. Fisher,et al.  The general sampling distribution of the multiple correlation coefficient , 1928 .

[9]  John C Gore,et al.  Task demand modulation of steady‐state functional connectivity to primary motor cortex , 2007, Human brain mapping.

[10]  P. Fransson.  How default is the default mode of brain function? Further evidence from intrinsic BOLD signal fluctuations , 2006, Neuropsychologia.

[11]  M. Fox,et al.  The global signal and observed anticorrelated resting state brain networks. , 2009, Journal of neurophysiology.

[12]  Abraham Z. Snyder,et al.  A method for using blocked and event-related fMRI data to study “resting state” functional connectivity , 2007, NeuroImage.

[13]  Jarl Risberg,et al.  Observations on the functional significance of regional cerebral blood flow in “resting” normal subjects , 1980, Neuropsychologia.

[14]  Catie Chang,et al.  Time–frequency dynamics of resting-state brain connectivity measured with fMRI , 2010, NeuroImage.

[15]  Adam Gazzaley,et al.  Measuring functional connectivity during distinct stages of a cognitive task , 2004, NeuroImage.

[16]  Kathryn M. McMillan,et al.  N‐back working memory paradigm: A meta‐analysis of normative functional neuroimaging studies , 2005, Human brain mapping.

[17]  D. S. Olton,et al.  Effects of fornix transection and cingulate cortical ablation on spatial memory in rhesus monkeys , 2004, Experimental Brain Research.

[18]  Thomas E. Nichols,et al.  Thresholding of Statistical Maps in Functional Neuroimaging Using the False Discovery Rate , 2002, NeuroImage.

[19]  Rainer Goebel,et al.  Independent component model of the default-mode brain function: Assessing the impact of active thinking , 2006, Brain Research Bulletin.

[20]  Michelle Hampson,et al.  Connectivity–behavior analysis reveals that functional connectivity between left BA39 and Broca's area varies with reading ability , 2006, NeuroImage.

[21]  C R Olson,et al.  Posterior cingulate cortex: sensory and oculomotor properties of single neurons in behaving cat. , 1992, Cerebral cortex.

[22]  M. Goldberg,et al.  Single neurons in posterior cingulate cortex of behaving macaque: eye movement signals. , 1996, Journal of neurophysiology.

[23]  D. Schacter,et al.  The Brain's Default Network , 2008, Annals of the New York Academy of Sciences.

[24]  E. Formisano,et al.  Functional connectivity as revealed by spatial independent component analysis of fMRI measurements during rest , 2004, Human brain mapping.

[25]  Kevin Murphy,et al.  The impact of global signal regression on resting state correlations: Are anti-correlated networks introduced? , 2009, NeuroImage.

[26]  Vinod Menon,et al.  Functional connectivity in the resting brain: A network analysis of the default mode hypothesis , 2002, Proceedings of the National Academy of Sciences of the United States of America.

[27]  Rupert Lanzenberger,et al.  Correlations and anticorrelations in resting-state functional connectivity MRI: A quantitative comparison of preprocessing strategies , 2009, NeuroImage.

[28]  M. D’Esposito,et al.  The neural basis of the central executive system of working memory , 1995, Nature.

[29]  M E Meyerand,et al.  Combining independent component analysis and correlation analysis to probe interregional connectivity in fMRI task activation datasets. , 2000, Magnetic resonance imaging.

[30]  Stephen M. Smith,et al.  Investigations into resting-state connectivity using independent component analysis , 2005, Philosophical Transactions of the Royal Society B: Biological Sciences.

[31]  D Curran-Everett,et al.  Multiple comparisons: philosophies and illustrations. , 2000, American journal of physiology. Regulatory, integrative and comparative physiology.

[32]  D. S. Olton,et al.  A comparative analysis of the role of fornix and cingulate cortex in memory: rats , 2004, Experimental Brain Research.

[33]  Anke Meyer-Bäse,et al.  Comparison of two exploratory data analysis methods for fMRI: unsupervised clustering versus independent component analysis , 2004, IEEE Transactions on Information Technology in Biomedicine.

[34]  B. Biswal,et al.  Simultaneous assessment of flow and BOLD signals in resting‐state functional connectivity maps , 1997, NMR in biomedicine.

[35]  Jieun Kim,et al.  Effects of Verbal Working Memory Load on Corticocortical Connectivity Modeled by Path Analysis of Functional Magnetic Resonance Imaging Data , 2002, NeuroImage.

[36]  P. Skudlarski,et al.  Brain Connectivity Related to Working Memory Performance , 2006, The Journal of Neuroscience.

[37]  Adam Gazzaley,et al.  Dynamic adjustments in prefrontal, hippocampal, and inferior temporal interactions with increasing visual working memory load. , 2008, Cerebral cortex.

[38]  V. Haughton,et al.  Frequencies contributing to functional connectivity in the cerebral cortex in "resting-state" data. , 2001, AJNR. American journal of neuroradiology.

[39]  D. Amaral,et al.  Macaque monkey retrosplenial cortex: III. Cortical efferents , 2003, The Journal of comparative neurology.

[40]  Tara A. Cairo,et al.  Functional connectivity reveals load dependent neural systems underlying encoding and maintenance in verbal working memory , 2006, Neuroscience.

[41]  Michelle Hampson,et al.  Changes in functional connectivity of human MT/V5 with visual motion input , 2004, Neuroreport.

[42]  J. Lurito,et al.  Correlations in Low-Frequency BOLD Fluctuations Reflect Cortico-Cortical Connections , 2000, NeuroImage.

[43]  G L Shulman,et al.  INAUGURAL ARTICLE by a Recently Elected Academy Member:A default mode of brain function , 2001 .

[44]  M. Greicius,et al.  Persistent default‐mode network connectivity during light sedation , 2008, Human brain mapping.

[45]  G. Shulman,et al.  Medial prefrontal cortex and self-referential mental activity: Relation to a default mode of brain function , 2001, Proceedings of the National Academy of Sciences of the United States of America.

[46]  John C Gore,et al.  Assessing functional connectivity in the human brain by fMRI. , 2007, Magnetic resonance imaging.

[47]  Daniel S. Margulies,et al.  Mapping the functional connectivity of anterior cingulate cortex , 2007, NeuroImage.

[48]  P. Goldman-Rakic,et al.  Functional magnetic resonance imaging of human prefrontal cortex activation during a spatial working memory task. , 1994, Proceedings of the National Academy of Sciences of the United States of America.