Electrocortical and hemodynamic measures of emotional and reward relevant scene perception
Filkowski, Megan M
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The origins of emotional and reward disorders, which are increasing in prevalence, can be associated with dysfunction of neural circuitry involved in emotional cue perception. By identifying the specific brain mechanisms involved in disorders of emotion and addiction, treatments such as neuromodulation can be better understood and refined. Here, we use recent developments in neuroimaging techniques, including steady state evoked potentials (ssVEP) and rapidly sampled functional magnetic resonance imaging (fMRI) to investigate the modulation of, and causal connectivity among brain regions involved in emotional and rewarding scene processing. Specifically, we were interested in individual differences in evaluative and neural responses to naturalistic scenes of cigarrette smoking in nicotine users, and acceleration-relevant scenes in thrill seekers. While event-related and steady-state evoked potential amplitudes were enhanced during arousing (pleasant and unpleasant), relative to neutral scenes, no interactions were found between nicotine users, thrill-seekers, and controls. Whole brain fMRI analysis revealed increased activation in nicotine users relative to controls in response to smoking cues in multiple brain regions including visual association cortex and reward-related medial prefrontal cortex. Granger causality analyses of rapidly sampled fMRI data found significant bidirectional connectivity between amygdala, fusiform gyrus, and orbitofrontal cortex, with variable connectivity patterns between groups in response to reward-relevant scene contents. The interpretation of patterns of EEG and fMRI reactivity and connectivity are discussed with respect to selective and evolved attention mechanisms.