Affective perception and imagery: A NIRS study.

The activation of cortical attention networks during affective picture processing has been extensively studied, whereas little is known about affective imagery. It is still unclear whether differences in emotional stimulus content are able to modulate visual cortex activation during imagery. Moreover, individual differences in emotional reactivity and imagery ability have not been investigated. The aim of this experiment was to examine these processes by means of near-infrared spectroscopy (NIRS). Thirty-five healthy adults were instructed to look at affective (disgust and happy) and neutral pictures and afterwards visualize them during multi-channel NIRS recording. Our main results indicated a differential involvement of parietal and occipital areas in the perception and imagery of affective pictures. In general, picture perception provoked increased oxygenated hemoglobin in occipital regions, whereas imagery was associated with an increase in parietal areas. Emotional content modulated activation of the left occipital cortex during both picture perception and imagery. Affective pictures (disgust and happy) provoked greater activation compared to neutral ones. Additionally, the self-rated imagery ability of the participants was positively correlated with their occipital activation during affective imagery. Thus, occipital activation might be crucial for the quality of imagery. In contrast, all correlations with emotional traits (e.g. trait disgust) and oxygenation were nonsignificant, which might be due to the fact that those personality factors predominantly modulate the activation of subcortical limbic structures which are not accessible with NIRS. 2011 Elsevier B.V. All rights reserved.