title: Perceived arousal of facial expressions of emotion modulates the N170, regardless of emotional category: Time domain and time-frequency dynamics.
abstract: Findings concerning the emotional modulation of the N170 component of the visual event-related potential are mixed. In the present report we tested the hypothesis that the emotional modulation of the N170 may be driven by the perceived emotional arousal of the stimuli, rather than by specific emotional categories. Fifty-four participants viewed facial expressions of anger, disgust, fear and happiness, plus low arousal neutral faces. All emotional categories were matched in arousal, while stimuli within each category varied parametrically in this dimension. The modulation of the electrocortical activity on the N170 time-window was analyzed in the time domain and via time-frequency decomposition. The effects of emotion and arousal were analyzed separately. In the time domain N170 amplitudes co-varied parametrically with perceived arousal, regardless of emotional category. This modulation was linearly associated with the power of the theta, alpha, and beta frequency bands. Moreover, fear was associated with a trend for increased N170 amplitudes, enhanced alpha power, and increased broad band inter-trial phase coherence. These results support the views that a) the activity in N170 time window is fundamentally modulated by perceived arousal, b) the modulation of the N170 may be the product of an increased evoked response, rather than the result of phase resetting processes, and c) facial expressions of fear retain some processing primacy, that may be related to their increased value as environmental cues.
authors.affiliation: Laboratory of Neuropsychophysiology, Faculty of Psychology and Educational Sciences, University of Porto, Portugal; School of Criminology, Faculty of Law, University of Porto, Portugal.
authors.forename: Pedro R
authors.initials: PR
authors.lastname: Almeida
authors.affiliation: Laboratory of Neuropsychophysiology, Faculty of Psychology and Educational Sciences, University of Porto, Portugal; Human Neurobehavioral Laboratory, Faculty of Education and Psychology, Catholic Unviersity of Portugal-Porto, Portugal.
authors.forename: Fernando
authors.initials: F
authors.lastname: Ferreira-Santos
authors.affiliation: Laboratory of Neuropsychophysiology, Faculty of Psychology and Educational Sciences, University of Porto, Portugal; Faculty of Medicine, University of Porto, Portugal; Mind, Brain Imaging and Neuroethics Research Unit, University of Ottawa Institute of Mental Health Research, Ottawa, Canada.
authors.forename: Pedro L
authors.initials: PL
authors.lastname: Chaves
authors.affiliation: Laboratory of Neuropsychophysiology, Faculty of Psychology and Educational Sciences, University of Porto, Portugal; Faculty of Medicine, University of Porto, Portugal. Electronic address: tiagopaiva@fpce.up.pt.
authors.forename: Tiago O
authors.initials: TO
authors.lastname: Paiva
authors.affiliation: Laboratory of Neuropsychophysiology, Faculty of Psychology and Educational Sciences, University of Porto, Portugal.
authors.forename: Fernando
authors.initials: F
authors.lastname: Barbosa
authors.affiliation: Laboratory of Neuropsychophysiology, Faculty of Psychology and Educational Sciences, University of Porto, Portugal.
authors.forename: João
authors.initials: J
authors.lastname: Marques-Teixeira
mesh_terms: D000328:Adult; D001143:Arousal / Q000502:physiology*; D004644:Emotions / Q000502:physiology*; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005149:Facial Expression; D005260:Female; D006801:Humans; D008297:Male; D010775:Photic Stimulation / Q000379:methods*; D013997:Time Factors; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult
keywords: EEG/ERP; Facial expressions of emotion; N170; Perceived arousal