Attentional capture by emotional information in Alzheimer’s disease

Abstract

Alzheimer’s disease (AD) is a neurodegenerative pathological condition involving widespread cerebral lesions and a dementia syndrome that mainly affects cognitive functions. Moreover, the attentional salience of emotion seems to be incorrectly processed in patients with AD (Hot et al., 2013). This phenomenon could be due to early atrophy of the amygdala, a structure largely involved in the detection of emotional salience (Klein-Koerkamp et al., 2014). By conducting an oculometric paradigm, we investigated the mechanism of attentional capture in AD in order to test its preservation during emotional processing. AD patients, as well as age-matched and young controls, performed pro-saccade (PS) and anti-saccade (AS) tasks on positive, negative, and neutral images presented on a computer screen at the left and right sides of a central fixation cross. In the PS task, participants were instructed to quickly move their gaze to the stimulus after its appearance. Conversely, in the AS task, they had to move their gaze to the opposite side of the stimulus. Throughout the experiment, the participants’ eye movements were recorded by an infrared eye-tracking camera. In the AS task, the age-matched controls made more mistakes for negative than for neutral stimuli, whereas AD patients made as many mistakes for both categories of stimuli. These data support our hypothesis, as they suggest a decrease in attentional capture of negative stimuli in AD patients, whereas this phenomenon seems to be preserved in age-matched controls. Nonetheless, we need to extend these results to a wider group of participants to strengthen our hypothesis. Our results also revealed that overall, AD patients made more mistakes than did the controls in the AS task. Therefore, we must ascertain whether our results in AD patients can be explained by a deficit in attentional capture of emotional stimuli, in accordance with our hypothesis, or by a decrease in inhibition abilities, resulting in a loss of selectivity and an increase in attentional capture of non-salient stimuli. Future investigations are required to determine whether this phenomenon applies to more complex stimuli (e.g., visual scenes) and to other sensorial modalities.