Emotion Effects on the N170: A Question of Reference?

Department of Psychology, Humboldt-Universität zu Berlin, Rudower Chaussee 18, 12489, Berlin, Germany, .
Brain Topography (Impact Factor: 3.47). 10/2012; 26(1). DOI: 10.1007/s10548-012-0261-y
Source: PubMed


We investigated whether face-specific processes as indicated by the N170 in event-related brain potentials (ERPs) are modulated by emotional significance in facial expressions. Results yielded that emotional modulations over temporo-occipital electrodes typically used to measure the N170 were less pronounced when ERPs were referred to mastoids than when average reference was applied. This offers a potential explanation as to why the literature has so far yielded conflicting evidence regarding effects of emotional facial expressions on the N170. However, spatial distributions of the N170 and emotion effects across the scalp were distinguishable for the same time point, suggesting different neural sources for the N170 and emotion processing. We conclude that the N170 component itself is unaffected by emotional facial expressions, with overlapping activity from the emotion-sensitive early posterior negativity accounting for amplitude modulations over typical N170 electrodes. Our findings are consistent with traditional models of face processing assuming face and emotion encoding to be parallel and independent processes.

Download full-text


Available from: Annekathrin Schacht, Feb 08, 2014
  • Source
    • "During this processing step, structural processing of a face takes place, and the brain distinguishes between faces and other visual objects (Bentin et al., 1996). VPP and N170 very likely reflect the same brain process, and their amplitudes vary depending on which reference is applied to the EEG data (Joyce and Rossion, 2005; Rellecke et al., 2013). Even though these components have been associated with structural face processing, their amplitudes may be modulated by facial expression as well (Hinijosa et al., 2015). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Parkinson's disease (PD) affects patients beyond the motor domain. According to previous evidence, one mechanism that may be impaired in the disease is face processing. However, few studies have investigated this process at the neural level in PD. Moreover, research using dynamic facial displays rather than static pictures is scarce, but highly warranted due to the higher ecological validity of dynamic stimuli. In the present study we aimed to investigate how PD patients process emotional and non-emotional dynamic face stimuli at the neural level using event-related potentials. Since the literature has revealed a predominantly right-lateralized network for dynamic face processing, we divided the group into patients with left (LPD) and right (RPD) motor symptom onset (right versus left cerebral hemisphere predominantly affected, respectively). Participants watched short video clips of happy, angry, and neutral expressions and engaged in a shallow gender decision task in order to avoid confounds of task difficulty in the data. In line with our expectations, the LPD group showed significant face processing deficits compared to controls. While there were no group differences in early, sensory-driven processing (fronto-central N1 and posterior P1), the vertex positive potential, which is considered the fronto-central counterpart of the face-specific posterior N170 component, had a reduced amplitude and delayed latency in the LPD group. This may indicate disturbances of structural face processing in LPD. Furthermore, the effect was independent of the emotional content of the videos. In contrast, static facial identity recognition performance in LPD was not significantly different from controls, and comprehensive testing of cognitive functions did not reveal any deficits in this group. We therefore conclude that PD, and more specifically the predominant right-hemispheric affection in left-onset PD, is associated with impaired processing of dynamic facial expressions, which could be one of the mechanisms behind the often reported problems of PD patients in their social lives.
    Full-text · Article · Jan 2016 · Neuropsychologia
  • Source
    • "However, in another recent study, investigating the N170 and EPN responses to arousing and non-arousing body parts, i.e., insulting versus pointing hand gestures, only EPN but not the N170 response was modulated by the affective arousal of the hand gestures (Flaisch & Schupp, 2013). Thus, previous research using other types of stimuli have provided evidence that the arousal-related EPN activity can overlap with the N170 component (Rellecke et al., 2013), but this is not always the case (Flaisch & Schupp, 2013). Regarding the effects of arousal on body processing, the present data do not allow resolving this issue. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The early visual event-related 'N170 response' is sensitive to human body configuration and it is enhanced to nude versus clothed bodies. We tested whether the N170 response as well as later EPN and P3/LPP responses to nude bodies reflect the effect of increased arousal elicited by these stimuli, or top-down allocation of object-based attention to the nude bodies. Participants saw pictures of clothed and nude bodies and faces. In each block, participants were asked to direct their attention towards stimuli from a specified target category while ignoring others. Object-based attention did not modulate the N170 amplitudes towards attended stimuli; instead N170 response was larger to nude bodies compared to stimuli from other categories. Top-down attention and affective arousal had additive effects on the EPN and P3/LPP responses reflecting later processing stages. We conclude that nude human bodies have a privileged status in the visual processing system due to the affective arousal they trigger.
    Full-text · Article · Sep 2014 · Biological Psychology
  • Source
    • "They suggest that the scalp distribution related to the EPN is sensitive to emotional facial expressions while the parallel distribution associated with the N170 is only sensitive to the structural processing of facial stimuli, and that topographies are largely affected by choice of reference. The EPN is more negative in response to emotional compared to neutral facial expressions and is characterized by a more posterior spatial distribution compared to the N170 ERP (Rellecke et al., 2013). Since studies that measured the N170 used different paradigms and different references, a summary of emotion modulation of the N170 ERP must be tentative. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Facial expressions are encoded via sensory mechanisms, but meaning extraction and salience of these expressions involves cognitive functions. We investigated the time course of sensory encoding and subsequent maintenance in memory via EEG. Twenty-nine healthy participants completed a facial emotion delayed match-to-sample task. P100, N170 and N250 ERPs were measured in response to the first stimulus, and evoked theta power (4-7Hz) was measured during the delay interval. Negative facial expressions produced larger N170 amplitudes and greater theta power early in the delay. N170 amplitude correlated with theta power, however larger N170 amplitude coupled with greater theta power only predicted behavioural performance for one emotion condition (Very Happy) out of six tested (see Supplemental Data). These findings indicate that the N170 ERP may be sensitive to emotional facial expressions when task demands require encoding and retention of this information. Furthermore, sustained theta activity may represent continued attentional processing that supports short-term memory, especially of negative facial stimuli. Further study is needed to investigate the potential influence of these measures, and their interaction, on behavioural performance.
    Full-text · Article · Jun 2014 · International journal of psychophysiology: official journal of the International Organization of Psychophysiology
Show more