Neurogenetic variations in enhanced perceptual vividness are linked to differences in task-related brain activity
36.3045, Sunday, 17-May, 2:45 pm - 6:45 pm, Banyan Breezeway
Mana Ehlers1, Jennifer Whitman1, Daniel Müller2, Adam Anderson3,4, Rebecca Todd1; 1Department of Psychology, University of British Columbia, 2Department of Psychiatry, University of Toronto and Neurogenetics Section, Centre for Addiction and Mental Health, 3Department of Psychology, University of Toronto, 4Department of Human Development, Cornell University
Growing evidence suggests that emotional stimuli are not only better remembered than mundane ones, but that affective salience alters their perception. In a previous study, we demonstrated that emotional events are perceived with the subjective experience of enhanced perceptual vividness, or EEV as assessed with a visual magnitude estimation task (Fig. 1) (Todd et al., 2012). More recently, we were able to show that marked individual differences in EEV can be partly explained by a genetic polymorphism in the ADRA2b gene associated with altered norepinephrine levels. Participants genotyped for the ADRA2b deletion variant had to estimate the magnitude of random noise overlaid on emotionally salient and neutral pictures while fMRI data was collected. EEV is indexed by the extent to which observers rate more emotionally arousing images as containing less overlaid noise, reflecting greater signal-to-noise ratio for the underlying image. Blood oxygenation level-dependent (BOLD) response was analyzed using a novel multivariate approach (Hunter and Takane, 2002). Constrained principle component analysis (CPCA) allows detection of those components or brain networks that account for most of the variance in the data that is directly related to the task. The analysis revealed that ADRA2b deletion carriers show higher activity in general task- and attention-related brain regions such as the visual cortex and parietal regions (Fig. 2). Moreover, EEV modulated activity in a network involving salience-related brain regions such as ACC, the caudate nucleus and early visual areas (Fig. 3) reflecting behavioral findings of greater EEV in ADRA2b deletion carriers. The present study underlines the effectiveness of CPCA to detect task-related brain networks. The findings suggest that common genetic differences linked to norepinephrine influence both brain activity related to overall attention to the magnitude estimation task and EEV modulated activity of salience related brain regions linked to subjective experience of emotionally enhanced perceptual vividness.