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 b 0.05) reduced the time to peak (TTP), the time after the peak at which the response returned to 50% of the peak amplitude (TA 50 ), 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, TA 50 , and the time for the response to reach 50% of the peak amplitude (T 50 ) 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. D

Caffeine-induced uncoupling of cerebral blood flow and oxygen metabolism: A calibrated BOLD fMRI study

“…A robust CBF decrease of 35% in response to caffeine consumption was observed, in good agreement with previous work Cameron et al, 1990;Field et al, 2003;Liu et al, 2004). However, we measured an accompanying decrease in the BOLD signal which, when analyzed in the context of a mathematical model of the BOLD effect (Davis et al, 1998), suggests that the CBF decrease is not accompanied by a change in CMRO 2 .…”

“…Its main action is to bind to adenosine receptors and block the actions of agonists at these receptors (Fredholm et al, 1999), causing vasoconstriction. The resulting decrease in baseline CBF has been demonstrated using various measurement techniques in humans Bendlin et al, 2006;Cameron et al, 1990;Field et al, 2003;Liu et al, 2004;Mathew and Wilson, 1985). In addition, fMRI has previously been used to study the effects of caffeine on the amplitude (Bendlin et al, 2006;Laurienti et al, 2002Laurienti et al, , 2003Mulderink et al, 2002) and temporal dynamics Liu et al, 2004) of the BOLD response, typically detecting a speeding up of the BOLD response that is compatible with a model for the vasculature in which vasoconstrictive agents cause the arterioles to become more responsive to stimulation (Behzadi and Liu, 2005).…”

Acute caffeine administration impact on working memory-related brain activation and functional connectivity in the elderly: A BOLD and perfusion MRI study

“…Medication was applied in a double-blinded way. One capsule (caffeine 200 mg or placebo) was taken per os 30 min prior to the MR imaging in agreement with previous investigations (Mulderink et al, 2002;Liu et al, 2004;Behzadi and Liu, 2006;Perthen et al, 2008 Participants performed an n-back task, a wellestablished WM task in fMRI (for example, see metaanalysis in (Owen et al, 2005)). Briefly, a sequence of letters was presented visually on an MR compatible canvas in the MRI scanner.…”

“…Even usual dietary caffeine consumption significantly interacts with the BOLD response and this is significantly greater in higher dose caffeine consumers (Laurienti et al, 2002). The exact interaction of caffeine on the BOLD response includes a quickening and shortening of the BOLD response in addition to an increase of the BOLD amplitude (Liu et al, 2004), reduction of the initial dip in the visual BOLD response (Behzadi and Liu, 2006) as well as an increase in the linearity of the BOLD response (Liu and Liau, 2010). One could postulate that the observed WM-load related BOLD increase after caffeine ingestion might be partly attributable to its direct vascular effect.…”

Chronic smoking and the BOLD response to a visual activation task and a breath hold task in patients with schizophrenia and healthy controls

“…A reduction in CBF should translate into an increased transit time (assuming no blood volume changes), and according to Friston et al (2000), this would slow down the dynamics of the BOLD signal and produce a delayed IRF [see Cohen et al (2002) for a discussion of this issue]. However, two brief within-subject CBF-lowering manipulations [hypocapnia (Cohen et al, 2002), caffeine (Liu et al, 2004)] have been associated with a reduced time-to-trough. On the other hand, patients with chronically lower CBF due to arterial stenosis (primarily left internal and middle cerebral arteries) did show a slower time to return to baseline after the peak response despite comparable behavioral performance to control subjects (Roc et al, 2006).…”