The oscillating brain: Complex and reliable

Phyllis Green and Randolph Cōwen Institute for Pediatric Neuroscience at the New York University Child Study Center, New York, NY, USA.
NeuroImage (Impact Factor: 6.36). 09/2009; 49(2):1432-45. DOI: 10.1016/j.neuroimage.2009.09.037
Source: PubMed

ABSTRACT The human brain is a complex dynamic system capable of generating a multitude of oscillatory waves in support of brain function. Using fMRI, we examined the amplitude of spontaneous low-frequency oscillations (LFO) observed in the human resting brain and the test-retest reliability of relevant amplitude measures. We confirmed prior reports that gray matter exhibits higher LFO amplitude than white matter. Within gray matter, the largest amplitudes appeared along mid-brain structures associated with the "default-mode" network. Additionally, we found that high-amplitude LFO activity in specific brain regions was reliable across time. Furthermore, parcellation-based results revealed significant and highly reliable ranking orders of LFO amplitudes among anatomical parcellation units. Detailed examination of individual low frequency bands showed distinct spatial profiles. Intriguingly, LFO amplitudes in the slow-4 (0.027-0.073 Hz) band, as defined by Buzsáki et al., were most robust in the basal ganglia, as has been found in spontaneous electrophysiological recordings in the awake rat. These results suggest that amplitude measures of LFO can contribute to further between-group characterization of existing and future "resting-state" fMRI datasets.

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Available from: Dylan G. Gee, Jul 21, 2015
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    • "Remarkably stable and reliable functional networks emerge when subjects are scanned in the absence of task demands, in the " resting-state " [Biswal et al., 2010; Shehzad et al., 2009]. These networks are often defined by temporal correlations in spontaneous low-frequency BOLD signal fluctuations between brain regions, and they are highly reproducible and consistent [Damoiseaux et al., 2006; Zuo et al., 2010]. This consistency has been demonstrated in large group studies, including across over 1,414 subjects and 35 centers [Biswal et al., 2010]. "
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    • "Higher ReHo may thus indicate higher synchronization of local field potential of neuronal activity in the human brain (Li et al, 2013). Fractional Amplitude of Low Frequency Fluctuations (fALFF, (Zuo et al., 2008; Zou et al., 2010)) quantifies the amplitude of low frequency oscillations (LFOs), and is defined, for the time course of each voxel, as the power within the low-frequency range (0.01-0.1 "
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