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Abstract
A widely used paradigm to understand human cortical activity associated with perception, attention, and emotion involves displaying scenes that depict realistic content while recording with electroencephalography (EEG) or magnetoencephalography (MEG). This paradigm has led to many scientific advances, and the approach is increasingly used in clinical settings. However, previous research found the early posterior negativity (EPN) primarily used as a measure of emotional arousal, was more strongly affected by nudist couple scenes than emotional content such as erotica and mutilated body content. The available evidence suggested that this may have occurred because the previously used EPN window may encompass activity more sensitive to the perception of bodies known as the N170. The extent of spatial and content-modulation differences between 130 – 200 ms versus 200 – 300 ms after scene onset was not well captured by the EEG system used in previous studies. To address this, the same scenes were presented using complementary high-density EEG and MEG with L2-Minimum-Norm-Estimation. The results suggested that both components are spatially similar, but they vary in their sensitivities to different content. While both periods were sensitive to bodies and emotion, the N170 was more affected by the emotional neutral nudist couples while the EPN is more sensitive to the other emotional categories. Additionally, pupil diameter suggested that the evoked physiological arousal of nudist content did not explain the strong N170 and EPN modulatory effects. The results were also found to be consistent between participants recruited from the University of Georgia in the United States of America and the University of Münster, Germany. This research also featured two mostly separate auxiliary aims. A well-studied, although inconsistently found, effect suggests that the N170 is larger when evoked by pictures of faces of a different race than the participant’s own. This was one of the first studies to recruit a meaningfully large sample of Black participants to address this topic and found no differences based on the participant’s identified race. In the last auxiliary aim, a within-participant manipulation of the scene presentation speed did not meaningfully change the relevant emotion-related scene evoked potentials and fields.