Paper Info
Title
Caffeine alters the temporal dynamics of the visual BOLD response.
Abstract
The blood oxygenation level-dependent (BOLD) responses to visual stimuli, using both a 1-s long single trial stimulus and a 20-s long block stimulus, were measured in a 4-T magnetic field both before and immediately after a 200-mg caffeine dose. In addition, resting levels of cerebral blood flow (CBF) were measured using arterial spin labeling. For the single trial stimulus, the caffeine dose significantly (p<0.05) reduced the time to peak (TTP), the time after the peak at which the response returned to 50% of the peak amplitude (TA50), and the amplitude of the poststimulus undershoot in all subjects (N=5). Other parameters, such as the full-width half-maximum (FWHM) and the peak amplitude, also showed significant changes in the majority of subjects. For the block stimulus, the TTP, TA50, and the time for the response to reach 50% of the peak amplitude (T50) were significantly reduced. In some subjects, oscillations were observed in the poststimulus portion of the response with median peak periods of 9.1 and 9.5 s for the single trial and block responses, respectively. Resting CBF was reduced by an average of 24%. The reproducibility of the results was verified in one subject who was scanned on 3 different days. The dynamic changes are similar to those previously reported for baseline CBF reductions induced by hypocapnia and hyperoxia.
Year
DOI
Venue
2004
10.1016/j.neuroimage.2004.07.061
NeuroImage
Keywords
DocType
Volume
BOLD responses,Hypocapnia,Hyperoxia
Journal
23
Issue
ISSN
Citations 
4
1053-8119
30
PageRank 
References 
Authors
2.64
6
8
Name
Order
Citations
PageRank
Thomas T Liu1102276.03
Yashar Behzadi239920.35
Khaled Restom343824.27
Kamil Uludag47511.67
Kun Lu5302.64
Giedrius T Buracas6544.18
David J Dubowitz712612.66
Richard B. Buxton847540.65