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. Author manuscript; available in PMC: 2012 Aug 1.
Published in final edited form as: Neuroimage. 2011 May 7;57(3):809–816. doi: 10.1016/j.neuroimage.2011.04.064

Table 2.

Absolute CBF and R2∗.

CBF ROI
CBF (ml/100 ml/min) R2* (s−1)
Pre-caffeine (baseline) 82.6 (4.4) 24.4 (1.1)
Pre-caffeine (stimulus) 124.6 (5.2)* 23.9 (1.1)*
Post-caffeine (baseline) 59.9 (3.5)* 27.1 (1.2)*
Post-caffeine (stimulus) 93.6 (4.8)* 26.6 (1.2)*

Mean (one s.e.m., *p<0.001), absolute values of CBF and R2∗ measured in the pre- and post-caffeine experiments (10 subjects). ‘Baseline' isa veraged over the 10 s prior to the start of the stimulus during which a gray background with a white square in the middle was presented. The stimulus response was averaged over the last 10 s of the stimulus and denotes the steady state response to the flashing checkerboard visual stimulus. Significance for the pre-caffeine stimulus response and the post-caffeine baseline shift were tested against the pre-caffeine baseline. Significance for the post-caffeine stimulus response was testing against the post-caffeine baseline.