Medial parietal cortex activation related to attention control involving alcohol cues

Abstract

Automatic attentional engagement toward and disengagement from alcohol cues play a role in alcohol use and dependence. In the current study, social drinkers performed a spatial cueing task designed to evoke conflict between such automatic processes and task instructions, a potentially important task feature from the perspective of recent dual-process models of addiction. Subjects received instructions either to direct their attention toward pictures of alcoholic beverages, and away from non-alcohol beverages; or to direct their attention toward pictures of non-alcoholic beverages, and away from alcohol beverages. Instructions were varied per block. Activation in medial parietal cortex was found during "approach alcohol" versus "avoid-alcohol" blocks. This region is associated with the, possibly automatic, shifting of attention between stimulus features. Subjects thus appeared to shift attention away from certain features of alcoholic cues when attention had to be directed toward their location. Further, activation in voxels located close to this region was negatively correlated with riskier drinking behavior. A tentative interpretation of the results is that risky drinking may be associated with a reduced automatic tendency to shift attention away from potentially distracting task-irrelevant alcohol cues. Future study is needed to test this interpretation, and to further determine the role of medial posterior regions in automatic alcohol-related attentional processes in general.

Keywords: addiction; alcohol; attention; dual-process; fMRI; medial posterior cortex.

Figure 1

Illustration of the task. The figure shows an example of valid probe trial in an approach alcohol block, or an invalid probe trial in an avoid-alcohol block. The probe appears at the location of the cue, requiring an “up” response.

Figure 2

FMRI activation for the “toward alcohol” – “away from alcohol” contrast. From left to right, sagittal, coronal and transversal views, left and right reversed. (A) Activation of the contrast “toward alcohol” versus “away from alcohol” blocks. Significant voxels are shown in white. Activation was found in medial parietal cortex, near the precuneus and posterior cingulate. (B) Interaction of the block contrast with AUDIT-scores: white voxels show the region where contrast values were significantly lower for individuals with higher AUDIT-scores. Activation was again found in medial parietal cortex, but somewhat more posterior.