Functional MRI of rat brain was performed at 2 Tesla following intravenous
injection of cocaine in order to 1) determine if changes in CBV and changes
in BOLD signal were regionally coupled in brain parenchyma, and 2) compare
the sensitivities of these imaging methods across different brain structur
es. Percent changes in CBV and BOLD relaxation rate were spatially and temp
orally coupled during this graded brain activation. The use of contrast age
nt increased functional sensitivity in all parenchymal brain structures, wi
th a strong but predictable dependence on the resting-state blood volume fr
action. (C) 2001 Wiley-Liss, Inc.