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Scale-Free Properties of the Functional Magnetic Resonance Imaging Signal during Rest and Task.
- Source :
-
Journal of Neuroscience . 9/28/2011, Vol. 31 Issue 39, p13786-13795. 10p. - Publication Year :
- 2011
-
Abstract
- It has been shown recently that a significant portion of brain electrical field potentials consists of scale-free dynamics. These scale-free brain dynamics contain complex spatiotemporal structures and are modulated by task performance. Here we show that the fMRI signal recorded from the human brain is also scale free; its power-law exponent differentiates between brain networks and correlates with fMRI signal variance and brain glucose metabolism. Importantly, in parallel to brain electrical field potentials, the variance and power-law exponent of the fMRI signal decrease during task activation, suggesting that the signal contains more long-range memory during rest and conversely is more efficient at online information processing during task. Remarkably, similar changes also occurred in task-deactivated brain regions, revealing the presence of an optimal dynamic range in the fMRI signal. The scale-free properties of the fMRI signal and brain electrical field potentials bespeak their respective stationarity and nonstationarity. This suggests that neurovascular coupling mechanism is likely to contain a transformation from nonstationarity to stationarity. In summary, our results demonstrate the functional relevance of scale-free properties of the fMRI signal and impose constraints on future models of neurovascular coupling. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 02706474
- Volume :
- 31
- Issue :
- 39
- Database :
- Academic Search Index
- Journal :
- Journal of Neuroscience
- Publication Type :
- Academic Journal
- Accession number :
- 175155905
- Full Text :
- https://doi.org/10.1523/JNEUROSCI.2111-11.2011