Neuroticism is associated with reduced oxygenation levels in the lateral prefrontal cortex following exposure to unpleasant images.

The aim of this study was to explore the prefrontal cortex response to emotional salient stimuli in subjects with high scores in Neuroticism (and low in Sensation Seeking) or high scores in Sensation Seeking (and low in Neuroticism) personality traits, -called now Neuroticism and Sensation Seeking groups-. For this purpose, we selected 24 females (mean age: 20; SD: 1.74 years) and assigned them to two different groups according to their extreme score in personality dimensions. Ten pleasant and ten unpleasant pictures from the International Affective Picture System were presented. Neuroticism group showed significant effects for valence at the lateral prefrontal cortex in both brain hemispheres. They showed higher Oxygenation for pleasant pictures, more significantly in the left (Z = 2.49, p = 0.01) than in the right hemisphere (Z = 2.19, p = 0.03). The highest differences were registered in ventral optodes. In contrast, Sensation Seeking group did not show significant differences in hemodynamic variables as depending on the valence of the pictures. These data suggest a differential functioning of the lateral prefrontal cortex, mainly the left ventrolateral cortex, in Neuroticism group to pleasant and unpleasant visual stimuli. We hypothesize that if the lateral prefrontal activity is low, it could be the result of an over-activation of the amygdala in response to unpleasant pictures in subjects with Neuroticism or negative emotionality. These activation patterns could be related to vulnerability to emotional disorders.