Quasi-periodic patterns (QPP): large-scale dynamics in resting state fMRI that correlate with local infraslow electrical activity.
Functional connectivity measurements from resting state blood-oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) are proving a powerful tool to probe both normal brain function and neuropsychiatric disorders. However, the neural mechanisms that coordinate these large networks are poorly understood, particularly in the context of the growing interest in network dynamics. Recent work in anesthetized rats has shown that the spontaneous BOLD fluctuations are tightly linked to infraslow local field potentials (LFPs) that are seldom recorded but comparable in frequency to the slow BOLD fluctuations. These findings support the hypothesis that long-range coordination involves low frequency neural oscillations and establishes infraslow LFPs as an excellent candidate for probing the neural underpinnings of the BOLD spatiotemporal patterns observed in both rats and humans. To further examine the link between large-scale network dynamics and infraslow LFPs, simultaneous fMRI and microelectrode recording were performed in anesthetized rats. Using an optimized filter to isolate shared components of the signals, we found that time-lagged correlation between infraslow LFPs and BOLD is comparable in spatial extent and timing to a quasi-periodic pattern (QPP) found from BOLD alone, suggesting that fMRI-measured QPPs and the infraslow LFPs share a common mechanism. As fMRI allows spatial resolution and whole brain coverage not available with electroencephalography, QPPs can be used to better understand the role of infraslow oscillations in normal brain function and neurological or psychiatric disorders.
Department of Biomedical Engineering, Emory University/Georgia Institute of Technology, 101 Woodruff Circle, Atlanta, GA 30322, USA. Electronic address: garth@gatech.edu.
Garth John
GJ
Thompson
Wen-Ju
WJ
Pan
Matthew Evan
ME
Magnuson
Dieter
D
Jaeger
Shella Dawn
SD
Keilholz
D000818:Animals; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging; D051381:Rats; D012146:Rest / Q000502:physiology*
BOLD; Blood oxygen level dependent; EEG; EPI; FWER; Functional magnetic resonance imaging; Infraslow oscillation; LFP; Local field potential; NPL; NPR; PPL; PPR; QPP; Quasi-periodic; S1FL; SGoF; Slow wave; Spatiotemporal dynamics; blood oxygen level dependent; echo-planar imaging; electroencephalography; fMRI; family-wise error rate; functional magnetic resonance imaging; local field potentials; negative peak on left; negative peak on right; positive peak on left; positive peak on right; primary somatosensory cortex of the forelimb region; quasi-periodic pattern; sequential goodness of fit