title: Cortical response of the ventral attention network to unattended angry facial expressions: an EEG source analysis study.
abstract: BACKGROUND
  We used an affective prime task composed of emotional (happy, angry, and neutral) prime faces and target words with either positive or negative valence. By asking subjects to attend to either the faces' emotional expression or to the glasses' shape, we assessed whether angry facial expressions were processed when they were unattended and task-irrelevant.
  
  
  METHODS
  We conducted a distributed source analysis on the corresponding event-related potentials focused on the early activity of face processing and attention networks' related areas. We also evaluated the magnitude of the affective priming effect.
  
  
  RESULTS
  We observed a reduction of occipitotemporal areas' (BA37) activation to unattended compared to attended faces and a modulation of primary visual areas' activity lateralization. The latter was more right lateralized for attended than for unattended faces, and emotional faces were more right lateralized than neutral ones only in the former condition. Affective priming disappeared when emotional expressions of prime faces were ignored. Moreover, an increased activation in the right temporo-parietal junction (TPJ), but not in the intraparietal sulcus, was observed only for unattended angry facial expressions at ∼170 ms after face presentation.
  
  
  CONCLUSIONS
  We suggest that attentional resources affect the early processing in visual and occipito-temporal areas, irrespective of the faces' threatening content. The disappearance of the affective priming effect suggests that when subjects were asked to focus on glasses' shape, attentional resources were not available to process the facial emotional expression, even though emotion-relevant and emotion-irrelevant features of the face were presented in the same position. On the other hand, unattended angry faces evoked a pre-attentive TPJ activity, which most likely represents a bottom-up trigger that signals their high behavioral relevance, although it is unrelated to task demands.
authors.affiliation: Basque Center on Cognition, Brain and Language San Sebastián, Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: Inuggi
authors.affiliation: Departamento de Psicología Básica y Metodología, University of Murcia Murcia, Spain.
authors.forename: Federica
authors.initials: F
authors.lastname: Sassi
authors.affiliation: Departamento de Psicología Básica y Metodología, University of Murcia Murcia, Spain.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Castillo
authors.affiliation: Departamento de Psicología Básica y Metodología, University of Murcia Murcia, Spain.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Campoy
authors.affiliation: Institute of Experimental Neurology, L'Istituto di Ricovero e Cura a Carattere Scientifico San Raffaele Milan, Italy.
authors.forename: Letizia
authors.initials: L
authors.lastname: Leocani
authors.affiliation: Servicio de Radiología, Hospital Morales Meseguer Murcia, Spain.
authors.forename: José M
authors.initials: JM
authors.lastname: García Santos
authors.affiliation: Departamento de Psicología Básica y Metodología, University of Murcia Murcia, Spain.
authors.forename: Luis J
authors.initials: LJ
authors.lastname: Fuentes
keywords: EEG source analysis; attention modulation; temporo–parietal junction; threatening facial expressions; ventral attentional network