Large-amplitude, spatially correlated fluctuations in BOLD fMRI signals during extended rest and early sleep stages

@article{citeulike:887325, abstract = {A number of recent studies of human brain activity using blood-oxygen-level-dependent (BOLD) fMRI and EEG have reported the presence of spatiotemporal patterns of correlated activity in the absence of external stimuli. Although these patterns have been hypothesized to contain important information about brain architecture, little is known about their origin or about their relationship to active cognitive processes such as conscious awareness and monitoring of the environment. In this study, we have investigated the amplitude and spatiotemporal characteristics of resting-state activity patterns and their dependence on the subjects' alertness. For this purpose, BOLD fMRI was performed at 3.0 T on 12 normal subjects using a visual stimulation protocol, followed by a 27 min rest period, during which subjects were allowed to fall asleep. In subjects who were asleep at the end of the scan, we found (a) a higher amplitude of BOLD signal fluctuation during rest compared with subjects who were awake at the end of the scan; (b) spatially independent patterns of correlated activity that involve all of gray matter, including deep brain nuclei; (c) many patterns that were consistent across subjects; (d) that average percentage levels of fluctuation in visual cortex (VC) and whole brain were higher in subjects who were asleep (up to 1.71\% and 1.16\%, respectively) than in those who were awake (up to 1.15\% and 0.96\%) at the end of the scan and were comparable with those levels evoked by intense visual stimulation (up to 1.85\% and 0.76\% for two subject groups); (e) no confirmation of correlation, positive or negative, between thalamus and VC found in earlier studies. These findings suggest that resting-state activity continues during sleep and does not require active cognitive processes or conscious awareness.}, author = {Fukunaga, Masaki and Horovitz, Silvina G. and van Gelderen, Peter and de Zwart, Jacco A. and Jansma, Martijn J. and Ikonomidou, Vasiliki N. and Chu, Renxin and Deckers, Roel H. and Leopold, David A. and Duyn, Jeff H. }, citeulike-article-id = {887325}, doi = {http://dx.doi.org/10.1016/j.mri.2006.04.018}, journal = {Magnetic Resonance Imaging}, keywords = {fmri, resting-state}, month = {October}, number = {8}, pages = {979--992}, posted-at = {2007-01-27 08:57:51}, priority = {3}, title = {Large-amplitude, spatially correlated fluctuations in BOLD fMRI signals during extended rest and early sleep stages}, url = {http://dx.doi.org/10.1016/j.mri.2006.04.018}, volume = {24}, year = {2006} }

TY - JOUR ID - citeulike:887325 L3 - citeulike-article-id:887325 TI - Large-amplitude, spatially correlated fluctuations in BOLD fMRI signals during extended rest and early sleep stages JF - Magnetic Resonance Imaging VL - 24 IS - 8 SP - 979 EP - 992 N2 - A number of recent studies of human brain activity using blood-oxygen-level-dependent (BOLD) fMRI and EEG have reported the presence of spatiotemporal patterns of correlated activity in the absence of external stimuli. Although these patterns have been hypothesized to contain important information about brain architecture, little is known about their origin or about their relationship to active cognitive processes such as conscious awareness and monitoring of the environment. In this study, we have investigated the amplitude and spatiotemporal characteristics of resting-state activity patterns and their dependence on the subjects' alertness. For this purpose, BOLD fMRI was performed at 3.0 T on 12 normal subjects using a visual stimulation protocol, followed by a 27 min rest period, during which subjects were allowed to fall asleep. In subjects who were asleep at the end of the scan, we found (a) a higher amplitude of BOLD signal fluctuation during rest compared with subjects who were awake at the end of the scan; (b) spatially independent patterns of correlated activity that involve all of gray matter, including deep brain nuclei; (c) many patterns that were consistent across subjects; (d) that average percentage levels of fluctuation in visual cortex (VC) and whole brain were higher in subjects who were asleep (up to 1.71% and 1.16%, respectively) than in those who were awake (up to 1.15% and 0.96%) at the end of the scan and were comparable with those levels evoked by intense visual stimulation (up to 1.85% and 0.76% for two subject groups); (e) no confirmation of correlation, positive or negative, between thalamus and VC found in earlier studies. These findings suggest that resting-state activity continues during sleep and does not require active cognitive processes or conscious awareness. KW - fmri KW - resting-state AU - Fukunaga, Masaki AU - Horovitz, Silvina AU - van Gelderen, Peter AU - de Zwart, Jacco AU - Jansma, Martijn AU - Ikonomidou, Vasiliki AU - Chu, Renxin AU - Deckers, Roel AU - Leopold, David AU - Duyn, Jeff PY - 2006/10// UR - http://dx.doi.org/10.1016/j.mri.2006.04.018 ER -