The Influence of Voxel-Wise RCBF Covariates in Pharmacological BOLD-FMRI Studies

Fernando O. Zelaya¹, Astrid Pauls¹, Owen O'Daly¹, Matthew Howard¹, David Alsop², Mitul Mehta¹

Several physiological modulators have been proposed as a means of reducing the inter-subject variance of BOLD-fMRI signals in group comparisons. In this abstract, we demonstrate that rCBF maps can be used as a voxel-wise co-variate in standard statistical models that compare brain activity maps, obtained from 2 groups of subjects who execute the same cognitive task after administration of a placebo and a psycho-active substance. The rCBF maps allow us to successfully identify statistically significant, drug-dependent differences that would otherwise appear as a type 2 error (false negative) using conventional analysis models.