Abstract
We examined the effects of two doses of alcohol (EtOH) on functional magnetic resonance imaging (fMRI) activation during a visual perception task. The Motor‐Free Visual Perception Test–Revised (MVPT‐R) provides measures of overall visual perceptual processing ability. It incorporates different cognitive elements including visual discrimination, spatial relationships, and mental rotation. We used the MVPT‐R to study brain activation patterns in healthy controls (1) sober, and (2) at two doses of alcohol intoxication with event‐related fMRI. The fMRI data were analyzed using a general linear model approach based upon a model of the time course and a hemodynamic response estimate. Additionally, a correlation analysis was performed to examine dose‐dependent amplitude changes. With regard to alcohol‐free task‐related brain activation, we replicate our previous finding in which SPM group analysis revealed robust activation in visual and visual association areas, frontal eye field (FEF)/dorsolateral prefrontal cortex (DLPFC), and the supplemental motor area (SMA). Consistent with a previous study of EtOH and visual stimulation, EtOH resulted in a dose‐dependent decrease in activation amplitude over much of the visual perception network and in a decrease in the maximum contrast‐to‐noise ratio (in the lingual gyrus). Despite only modest behavior changes (in the expected direction), significant dose‐dependent activation increases were observed in insula, DLPFC, and precentral regions, whereas dose‐dependent activation decreases were observed in anterior and posterior cingulate, precuneus, and middle frontal areas. Some areas (FEF/DLPFC/SMA) became more diffusely activated (i.e., increased in spatial extent) at the higher dose. Alcohol, thus, appears to have both global and local effects upon the neural correlates of the MVPT‐R task, some of which are dose dependent. Hum. Brain Mapping 21:15–26, 2004. © 2003 Wiley‐Liss, Inc.