Paper Info
Title
Caffeine increases the temporal variability of resting-state BOLD connectivity in the motor cortex.
Abstract
Correlations between spontaneous fluctuations in the blood oxygenation level dependent (BOLD) signal measured with functional MRI are finding increasing use as measures of functional connectivity in the brain, where differences can potentially predict cognitive performance and diagnose disease. Caffeine, which is a widely consumed neural stimulant and vasoactive agent, has been found to decrease the amplitude and correlation of resting-state BOLD fluctuations, and hence is an important factor to consider in functional connectivity studies. However, because the BOLD signal is sensitive to neural and vascular factors, the physiological mechanisms by which caffeine alters spontaneous BOLD fluctuations remain unclear. Resting-state functional connectivity has traditionally been assessed using stationary measures, such as the correlation coefficient between BOLD signals measured across the length of a scan. However, recent work has shown that the correlation of resting-state networks can vary considerably over time, with periods as short as 10s. In this study, we used a sliding window correlation analysis to assess temporal variations in resting-state functional connectivity of the motor cortex before and after caffeine ingestion. We found that the temporal variability of BOLD correlation was significantly higher following a caffeine dose, with transient periods of strong correlation alternating with periods of low or negative correlation. This phenomenon was primarily due to increased variability in the phase difference between BOLD time courses in the left and right motor cortices. These results indicate that caffeine may cause underlying spontaneous neural fluctuations to go in and out of coherence more frequently, and emphasizes the need to consider non-stationary measures when studying changes in functional connectivity.
Year
DOI
Venue
2012
10.1016/j.neuroimage.2011.10.001
NeuroImage
Keywords
Field
DocType
Nonstationary,Functional MRI,Resting-state network,Temporal dynamics,Correlation,Spectral decomposition
Brain mapping,Developmental psychology,Caffeine,Correlation coefficient,Neuroscience,Resting state fMRI,Psychology,Correlation,Motor cortex,Effects of sleep deprivation on cognitive performance,Correlation analysis
Journal
Volume
Issue
ISSN
59
3
1053-8119
Citations 
PageRank 
References 
16
0.87
15
Authors
2
Name
Order
Citations
PageRank
Anna Leigh Rack-Gomer1331.76
Thomas T Liu2102276.03