Early (M170) activation of face-specific cortex by face-like objects

The tendency to perceive faces in random patterns exhibiting configural properties of faces is an example of pareidolia. Perception of 'real' faces has been associated with a cortical response signal arising at approximately 170 ms after stimulus onset, but what happens when nonface objects are perceived as faces? Using magnetoencephalography, we found that objects incidentally perceived as faces evoked an early (165 ms) activation in the ventral fusiform cortex, at a time and location similar to that evoked by faces, whereas common objects did not evoke such activation. An earlier peak at 130 ms was also seen for images of real faces only. Our findings suggest that face perception evoked by face-like objects is a relatively early process, and not a late reinterpretation cognitive phenomenon. NeuroReport 20:403-407 (C) 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins

Mind Perception: Real but Not Artificial Faces Sustain Neural Activity beyond the N170/VPP

Faces are visual objects that hold special significance as the icons of other minds. Previous researchers using event-related potentials (ERPs) have found that faces are uniquely associated with an increased N170/vertex positive potential (VPP) and a more sustained frontal positivity. Here, we examined the processing of faces as objects vs. faces as cues to minds by contrasting images of faces possessing minds (human faces), faces lacking minds (doll faces), and non-face objects (i.e., clocks). Although both doll and human faces were associated with an increased N170/VPP from 175–200 ms following stimulus onset, only human faces were associated with a sustained positivity beyond 400 ms. Our data suggest that the N170/VPP reflects the object-based processing of faces, whether of dolls or humans; on the other hand, the later positivity appears to uniquely index the processing of human faces—which are more salient and convey information about identity and the presence of other minds

Using transcranial Direct Current Stimulation (tDCS) to modulate the face inversion effect on the N170 ERP component

This is the final version. Available from the Cognitive Science Society via the link in this recordIn the present study, we combined tDCS and EEG to examine the electrophysiological responses to the tDCS-induced effects on the face inversion effect showed in recent studies. A double-blind procedure with a between-subjects design (n=48) was used with the subjects, recruited from the student population, being randomly assigned to either tDCS anodal or sham condition. The tDCS stimulation was delivered over the DLPFC at Fp3 site for 10 min at an intensity of 1.5mA while subjects engaged in an old/new recognition task traditionally used to obtain the inversion effect. The behavioural results generally confirmed previous findings. Critically, the results from the N170 show an effect of tDCS. Specifically, the tDCS procedure was able to modulate the N170 peak component by reducing the inversion effect on the latencies (i.e. less delay between upright and inverted faces) and by increasing the inversion effect on the amplitudes (i.e. larger N170 for inverted vs upright faces). We interpret the results based on the previous literature in regard to the inversion effect on the N170 component.European Union Horizon 2020Economic and Social Research Council (ESRC

The N170 event-related potential differentiates congruent and incongruent gaze responses in gaze leading

To facilitate social interactions, humans need to process the responses that other people make to their actions, including eye movements that could establish joint attention. Here, we investigated the neurophysiological correlates of the processing of observed gaze responses following the participants’ own eye movement. These observed gaze responses could either establish, or fail to establish, joint attention. We implemented a gaze leading paradigm in which participants made a saccade from an on-screen face to an object, followed by the on-screen face either making a congruent or incongruent gaze shift. An N170 event-related potential was elicited by the peripherally located gaze shift stimulus. Critically, the N170 was greater for joint attention than non-joint gaze both when task-irrelevant (Experiment 1) and task-relevant (Experiment 2). These data suggest for the first time that the neurocognitive system responsible for structural encoding of face stimuli is affected by the establishment of participant-initiated joint attention

Category Specificity in Early Perception: Face and Word N170 Responses Differ in Both Lateralization and Habituation Properties

N170 event-related potential (ERP) responses to both faces and visual words raises questions about category specific processing mechanisms during early perception and their neural basis. Topographic differences across word and face N170s suggests a form of category specific processing in early perception – the word N170 is consistently left-lateralized, while less consistent evidence supports a right-lateralization for the face N170. Additionally, the face N170 shows a reduction in amplitude across consecutive individual faces, a form of habituation that might differ across studies thereby helping to explain inconsistencies in lateralization. This effect remains unexplored for visual words. The current study directly contrasts N170 responses to words and faces within the same subjects, examining both category-level habituation and lateralization effects. ERP responses to a series of different faces and words were collected under two contexts: blocks that alternated faces and words vs. pure blocks of a single category designed to induce category-level habituation. Global and occipito-temporal measures of N170 amplitude demonstrated an interaction between category (words, faces) and block context (alternating categories, same category). N170 amplitude demonstrated class-level habituation for faces but not words. Furthermore, the pure block context diminished the right-lateralization of the face N170, pointing to class-level habituation as a factor that might drive inconsistencies in findings of right-lateralization across different paradigms. No analogous effect for the word N170 was found, suggesting category specificity for this form of habituation. Taken together, topographic and habituation effects suggest distinct forms of perceptual processing drive the face N170 and the visual word form N170

Nägude ja majade tajukorrelaatide võrdlus mõõdetuna elektroentsefalograafia meetodiga

Käesoleva seminaritöö raames on uuritud nägude ja mittenägude tajumise erinevusi. Selleks näidati katseisikutele 10 ms vältel stiimuleid, millel oli kujutatud üks kahest erineva kategooria kujutisest (nägu või maja). Esimesel kategoorial oli katseisikutele teadmata kaks alamkategooriat (tuttav nägu või võõras nägu). Stiimulid olid pikselleeritud neljal erineval astmel (maskeerimisastmed) ning katseisikud pidid vastama, millisesse kategooriasse kuuluvat kujutist (nägu või maja) nad nägid. Samal ajal, kui katseisikud ülesannet täitsid, mõõdeti nende ajutegevust EEG abil. Igal maskeerimisastmel tuvastati tuttavaid nägusid paremini kui võõraid nägusid. Kolmel esimesel maskeerimisastmel tuvastati tuttavaid nägusid paremini kui majasid, võõraste nägude ja majade vahel erinevusi ei ilmnenud. Tuttavate nägude jaoks ilmnenud käitumuslik efekt võrreldes võõraste nägudega kajastus ka EEG-ga mõõdetud sündmuspotentsiaalides. Mainitud tingimuste vahel ilmnesid erinevused alates 200 ms pärast stiimuli esitamist. Sündmuspotentsiaalid erinesid olenevalt sellest, millist stiimulit näidati eelneval katsekorral, need erinevused hakkasid ilmnema vahetult enne 200 ms möödumist stiimuli esitamisest.http://www.ester.ee/record=b4431516~S1*es

Combined effects of inversion and feature removal on N170 responses elicited by faces and car fronts

The final publication is available at Elsevier via http://dx.doi.org/10.1016/j.bandc.2013.01.002. © 2013. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/The face-sensitive N170 is typically enhanced for inverted compared to upright faces. Itier, Alain, Sedore, and McIntosh (2007) recently suggested that this N170 inversion effect is mainly driven by the eye region which becomes salient when the face configuration is disrupted. Here we tested whether similar effects could be observed with non-face objects that are structurally similar to faces in terms of possessing a homogeneous within-class first-order feature configuration. We presented upright and inverted pictures of intact car fronts, car fronts without lights, and isolated lights, in addition to analogous face conditions. Upright cars elicited substantial N170 responses of similar amplitude to those evoked by upright faces. In strong contrast to face conditions however, the car-elicited N170 was mainly driven by the global shape rather than the presence or absence of lights, and was dramatically reduced for isolated lights. Overall, our data confirm a differential influence of the eye region in upright and inverted faces. Results for car fronts do not suggest similar interactive encoding of eye-like features and configuration for non-face objects, even when these objects possess a similar feature configuration as faces

The role of eyes in early face processing: a rapid adaptation study of the inversion effect.

This is the peer reviewed version of the following article: Nemrodov, D. and Itier, R. J. (2011), The role of eyes in early face processing: A rapid adaptation study of the inversion effect. British Journal of Psychology, 102: 783–798. doi:10.1111/j.2044-8295.2011.02033.x, which has been published in final form at https://dx.doi.org/10.1111/j.2044-8295.2011.02033.x. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.The current study employed a rapid adaptation procedure to test the neuronal mechanisms of the face inversion effect (FIE) on the early face-sensitive event-related potential (ERP) component N170. Five categories of face-related stimuli (isolated eyes, isolated mouths, eyeless faces, mouthless faces, and full faces) and houses were presented in upright and inverted orientations as adaptors for inverted full face test stimuli. Strong adaptation was found for all face-related stimuli except mouths. The adaptation effect was larger for inverted than upright stimuli, but only when eyes were present. These results underline an important role of eyes in early face processing. A mechanism of eye-dependent orientation sensitivity during the structural encoding stage of faces is proposed.103305-1/Canadian Institutes of Health Research89822-1/Canadian Institutes of Health ResearchMOP-89822/Canadian Institutes of Health Researc

The impact of task relevance and degree of distraction on stimulus processing

Peer reviewedPublisher PD

Neurophysiological markers of emotion processing in burnout syndrome

The substantial body of research employing subjective measures indicates that burnout syndrome is associated with cognitive and emotional dysfunctions. The growing amount of neurophysiological and neuroimaging research helps in broadening existing knowledge of the neural mechanisms underlying core burnout components (emotional exhaustion and depersonalization/cynicism) that are inextricably associated with emotional processing. In the presented EEG study, a group of 93 participants (55 women; mean age = 35.8) were selected for the burnout group or the demographically matched control group on the basis of the results of the Maslach Burnout Inventory - General Survey (MBI-GS) and the Areas of Worklife Survey (AWS). Subjects then participated in an EEG experiment using two experimental procedures: a facial recognition task and viewing of passive pictures. The study focuses on analyzing event-related potentials (ERPs): N170, VPP, EPN, and LPP, as indicators of emotional information processing. Our results show that burnout subjects, as compared to the control group, demonstrate significantly weaker response to affect-evoking stimuli, indexed by a decline in VPP amplitude to emotional faces and decreased EPN amplitude in processing emotional scenes. The analysis of N170 and LPP showed no significant between-group difference. The correlation analyses revealed that VPP and EPN, which are ERP components related to emotional processing, are associated with two core burnout symptoms: emotional exhaustion and cynicism. To our knowledge, we are one of the first research groups to use ERPs to demonstrate such a relationship between neurophysiological activity and burnout syndrome in the context of emotional processing. Thus, in conclusion we emphasized that the decreased amplitude of VPP and EPN components in the burnout group may be a neurophysiological manifestation of emotional blunting and may be considered as neurophysiological markers of emotional exhaustion and cynicism. Additionally, we did not observe a decrease in LPP, which may be considered as a marker that significantly differentiates burnout from depression