Attentional capture by emotional information in Alzheimer’s disease : automatic and motivational processes

Abstract

Based on recent work, the attentional salience of emotion seems to be incorrectly processed in Alzheimer’s Disease (AD). This phenomenon could be due to early amygdala atrophy, a structure involved in the detection of emotional salience. Using attentional tasks, we investigated the mechanism of attentional capture in AD to test its preservation during emotional processing. AD patients and age-matched controls performed pro-saccade, anti-saccade and dot-probe tasks on positive, negative, and neutral images presented on a computer screen. In the pro-saccade task, participants were instructed to quickly move their gaze to the stimulus after its appearance. Conversely, in the anti-saccade task, they had to move their gaze to the opposite side of the stimulus. Finally, in the dot-probe task, they had to focus their attention on a target preceded by two probes, one neutral, and one emotional. The emotional one could be presented on the same side as the target (congruent condition), or on the opposite side (incongruent condition). In the pro-saccade and anti-saccade tasks, age-matched controls respectively moved their gaze more quickly and frequently to negative than to neutral stimuli, whereas AD patients moved their gaze equally for both categories of stimuli. In the dot-probe task, age-matched controls were slower to focus on the target preceded by a negative probe in the congruent than in the incongruent condition, whereas AD patients showed no differences between both conditions. These results support our hypothesis, as they suggest a decrease of emotional influence on attentional processes in AD patients.