Spatial localization and resolution of BOLD fMRI

It has been demonstrated that the blood-oxygenation-level-dependent (BOLD) fMRI initial dip allows us to resolve (without differential subtraction) st ructures of the order of 0.5 mm. However, recent results support the propos ition that even the later, positive BOLD fMRI signal component can allow us to resolve structures less than 1 mm in size by using differential subtrac tion when the signal-to-noise ratio is high. So, with a sufficient signal-t o-noise ratio, the later, positive component should be useable as a probe f or testing cognitive neuroscientific hypotheses that predict neuroanatomica l dissociations of less than 1 mm.