Peripherally Presented Emotional Scenes: A Spatiotemporal Analysis of Early ERP Responses

Abstract

Recent findings from event-related potentials (ERPs) studies provided strong evidence that centrally presented emotional pictures could be used to assess affective processing. Moreover, several studies showed that emotionally charged stimuli may automatically attract attention even if these are not consciously identified. Indeed, such perceptive conditions can be compared to those typical of the peripheral vision, particularly known to have low spatial resolution capacities. The aim of the present study was to characterize at behavioral and neural levels the impact of emotional visual scenes presented in peripheral vision. Eighteen participants were asked to categorize neutral and unpleasant pictures presented at central (0°) and peripheral eccentricities (-30 and +30°) while ERPs were recorded from 63 electrodes. ERPs were analysed by means of spatio-temporal principal component analyses (PCA) in order to evaluate influences of the emotional content on ERP components for each spatial position (central vs. peripheral). Main results highlight that affective modulation of early ERP components exists for both centrally and peripherally presented pictures. These findings suggest that, for far peripheral eccentricities as for central vision, the brain engages specific resources to process emotional information.

Sensitivity to emotional scene content outside the focus of attention

“…2 This finding lends support to the hypothesis that emotional content captures attention extrafoveally (see Carretié, 2014). This interpretation is consistent with prior eye-movement research showing selective orienting towards extrafoveal emotional scenes when competing with neutral stimuli (Alpers, 2008;Calvo & Lang, 2004;Kissler & Keil, 2008;McSorley & van Reekum, 2013;Nummenmaa et al, 2006); and with electrocortical research revealing enhanced ERP activity for extrafoveal emotional, relative to neutral, singly presented scenes (De Cesarei et al, 2009;Keil, Moratti, Sabatinelli, Bradley & Lang, 2005;Rigoulot et al, 2008). In general, in the service of identification of motivationally relevant stimuli and preparation for goal-directed action, emotional cues would preferentially draw attention, thus reducing the available resources and disrupting the processing of concurrent or immediately following neutral stimuli (Bradley et al, 2012).…”

“…Emotional scenes in the near periphery (8.2°; but not farther: 16.4°) elicited a negative ERP differential (relative to neutral scenes) over temporo-occipital scalp regions (200-280 ms), and a later positivity over centro-parietal areas (400-800 ms) (De Cesarei, Codispoti & Schupp, 2009). An affective modulation of early ERPs (145 ms) in lateral occipital and inferotemporal cortices has also been reported for emotional pictures at a 30°eccentricity (Rigoulot et al, 2008). Altogether, in the absence of low-level image differences between emotional and neutral scenes, these findings suggest that emotional content is perceived and captures attention extrafoveally.…”

Topographic ERP Analyses: A Step-by-Step Tutorial Review

“…[55,56]). To return to the example in the preceding section, these analyses serve to identify the sequence of ''letters''.…”

Beyond Conventional Event-related Brain Potential (ERP): Exploring the Time-course of Visual Emotion Processing Using Topographic and Principal Component Analyses

“…Finally, we should point out that tPCA may help not only to break down late ERP effects (e.g., P300) into functionally distinct components during visual emotion processing, but may also be used to dissect earlier sensory stages in the visual ERPs to emotional stimuli (e.g., [89,90]). For instance, PCA has been exploited to disentangle overlapping ERP components modulated by anxiety-related biases during emotion perception (including sub-components of the Contingent Negative Variation, see [91]); and to investigate effects of depression on visual emotion processing (including the P300 component, see [92]).…”