Search

International audience; The main goal of present work is to gain new insight into the temporal dynamics underlying the voluntary memory control for neutral faces associated with neutral, positive and negative contexts. A directed forgetting (DF) procedure was used during the recording of EEG to answer the question whether is it possible to forget a face that has been encoded within a particular emotional context. A face-scene phase in which a neutral face was showed in a neutral or emotional scene (positive, negative) was followed by the voluntary memory cue (cue phase) indicating whether the face had to-be remember or to-be-forgotten (TBR and TBF). Memory for faces was then assessed with an old/new recognition task. Behaviorally, we found that it is harder to suppress faces-in-positive-scenes compared to faces-in-negative and neutral-scenes. The temporal information obtained by the ERPs showed: 1) during the face-scene phase, the Late Positive Potential (LPP), which indexes motivated emotional attention, was larger for faces-in-negative-scenes compared to faces-in-neutral-scenes. 2) Remarkably, during the cue phase, ERPs were significantly modulated by the emotional contexts. Faces-in-neutral scenes showed an ERP pattern that has been typically associated to DF effect whereas faces-in-positive-scenes elicited the reverse ERP pattern. Faces-in-negative scenes did not show differences in the DF-related neural activities but larger N1 amplitude for TBF vs. TBR faces may index early attentional deployment. These results support the hypothesis that the pleasantness or unpleasantness of the contexts (through attentional broadening and narrowing mechanisms, respectively) may modulate the effectiveness of intentional memory suppression for neutral information.

Objective The aim of this study was to characterize the temporal dynamics of face encoding and recognition as a function of inversion. Methods Event-related potentials (ERPs) were recorded while participants performed a recognition task in which orientation was manipulated both at study and retrieval. This procedure was used to compare the effects of same and different orientation at encoding and retrieval on early and later recognition-related components. Results Changes in orientation from encoding to retrieval led to worse recognition performance, as compared to unchanged face orientations. Changes in face orientation were also associated with longer N170 latencies at retrieval. Later memory related ERP components (>300 ms) were affected by inversion and changes in orientation in a graded manner: upright faces encoded upright yielded the largest old–new effects, followed by inverted faces encoded inverted and finally by faces that differed in orientation from encoding to retrieval. Conclusions These results suggest that the disruption of configural information caused by inversion has different effects on memory depending on whether the face is presented at retrieval with the same orientation as at encoding. Significance These findings show a dynamic interplay between perception and memory in which face orientation interacts with structural encoding and memory.

A rapid neural adaptation procedure and Event Related Potentials (ERPs) were employed to study individual differences in Good and Bad recognizers in face perception. The major goal was to characterize the sensitivity of the P100 and the N170 to the identity repetition effect as a function of inter-individual perceptual abilities. For these purposes an integrated methodological approach was used in which a self-report, a standardized test and behavioral performances were combined with ERPs measures. Specifically, two groups of face recognizers (Good and Bad recognizers) were selected by means of a self-report questionnaire on face recognition abilities (The Italian Face Abilities Questionnaire) and the scoring at the Cambridge Face Memory Test. The P100 showed an early neural tuning for faces in Good recognizers. The N170 triggered by the adaptor showed face specificity compared to cars but, importantly, only Good recognizers showed a decreased amplitude of N170 for test faces of the same identity compared to test faces of different identity while this was not the case for Bad recognizers. These results show that ERPs are a suitable and sensitive tool to tap individual differences in face recognition. In conclusion, our results show the importance of considering inter-individual different perceptual abilities in face processing research.

The relation between attractiveness and motor affordance is a key topic in design and has not yet been investigated electrophysiologically. In this respect, action affordance and attractiveness represent two crucial dimensions in object processing (specifically for tools). In light of this evidence, Event Related Potentials (ERPs) enabled us to gain new insights into the time course of the interaction between these two dimensions during an explicit tool evaluation task. Behaviorally, tools that were judged as high affording and high attractive yielded faster response times than those judged as low affording and low attractive. The ERP results showed that early processes related to sensory gating and feature extraction (N100) were sensitive to both affordance and attractiveness; the P200 was dominated by affordance, indexing a facilitated access to motor action representation. The N300, P300 and the Late Positive Potential (LPP) showed enhanced responses for highly affording/attractive tools, reflecting the interconnection between attractiveness and affordance. Later responses were entirely affected by attractiveness, suggesting additional affective responses evoked by desirable tools. We are showing that things that are perceived as more functional and attractive have a privileged neural activation in the time course of tool evaluation, for the first time.

Event related potentials (ERPs) were employed to investigate whether and when brain activity related to face recognition varies according to the processing level undertaken at encoding. Recognition was assessed when preceded by a "shallow" (orientation judgement) or by a "deep" study task (occupation judgement). Moreover, we included a further manipulation by presenting at encoding faces either in the upright or inverted orientation. As expected, deeply encoded faces were recognized more accurately and more quickly with respect to shallowly encoded faces. The ERP showed three main findings: i) as witnessed by more positive-going potentials for deeply encoded faces, at early and later processing stage, face recognition was influenced by the processing strategy adopted during encoding; ii) structural encoding, indexed by the N170, turned out to be "cognitively penetrable" showing repetition priming effects for deeply encoded faces; iii) face inversion, by disrupting configural processing during encoding, influenced memory related processes for deeply encoded faces and impaired the recognition of faces shallowly processed. The present study adds weight to the concept that the depth of processing during memory encoding affects retrieval. We found that successful retrieval following deep encoding involved both familiarity- and recollection-related processes showing from 500 ms a fronto-parietal distribution, whereas shallow encoding affected only earlier processing stages reflecting perceptual priming.

The aim of the current study was to investigate the electrophysiological correlates of face processing in different groups of subjects selected on the basis of their poor, low or high face ability, namely Congenital Prosopagnosics, Bad and Good face recognizers. We examined how the Event Related Potentials (ERP) components were modulated by individual differences. The study was characterized by two sessions, in the first session face ability was evaluated by means of two tests: the Cambridge Face Memory Test and the Cambridge Face Perception Test. Subjects whose scores fell within two and one SDs below the mean were classified as Congenital Prosopagnosics and Bad recognizers respectively; whereas those that fell within one SD above the mean were classified as Good recognizers. In the second session, ERP were recorded during a same/different task with the procedure of the neural rapid visual adaptation. A modulation of neural activity emerged as function of individual differences. Specifically, the N170 component – a face-specific neural marker – showed an adaptation pattern according to different groups. Amplitude and latency varied as function of face ability showed by subjects, indicating a specific brain activity linked to individual differences in face processing.

In order to tap the electrophysiological correlates of the perceptual and structural encoding stages of face processing, we investigated how inversion and familiarity affect the face-specific event-related potentials (ERPs) components. ERPs were recorded while participants performed a familiarity judgment task with upright and inverted photographs of famous and unknown faces. The early P100 component was found to be sensitive to facial configuration that is disrupted by face inversion. Noteworthy, in addition to the ongoing effect of orientation, an effect of familiarity, although limited to upright faces, emerged at the processing stage indexed by N170. Later on, as witnessed by the P250 component, the familiarity effect was generalized to both upright and inverted faces with a larger amplitude for inverted famous faces. All in all, the present results suggest that the face structural encoding stage is cognitively permeable by higher-order factors such as familiarity, especially when familiarity is crucial for mastering the task. From a more general viewpoint, these results indicate that face processing is subserved by multiple mechanisms in which structural (i.e. orientation) and semantic (i.e. familiarity) factors begin to interact at early processing stages with different time courses. The electrophysiological correlates of these mechanisms are documented by the differential involvement of the major ERP components in the "familiarity check". With upright faces familiarity affects the N170 component, while with inverted faces it affects later components, in keeping with a prolonged time course of the familiarity decision when orientation is not upright.

The ability to encode together emotional attributes and face identity has a key role in human interactions. Several neuroimaging studies investigated the emotional stimuli encoding but a still open question is the temporal dynamic of the interaction between emotion and memory. We used ERPs with the major goal to investigate whether and when the emotional processing effectiveness drives the encoding. Emotional processing (Early frontal positivity) and subsequent memory (Dm effect) was investigated for faces with either happy, fearful or neutral expressions at encoding. At retrieval all faces were presented with neutral expression and participants were to judge old and new faces. ERP results showed a very early interaction between emotion and successful encoding of faces. Furthermore, the Dm amplitude was modulated as a function of the emotional attributes of the stimuli. All in all, our data suggest that the emotional processing influence encoding through two distinct mechanisms. At an early latency, the effectiveness of salience-related processing may benefit memory in a nonspecific way, while later on a valence-related facilitation may enhance memory formation, particularly for fearful faces.

Objective Time processing in the millisecond-to-minute range is reflected by Event-Related Potentials (ERPs), but the neural circuits of timing remains controversial. In the present study we investigated the role of different cortical areas in the processing of basic temporal information using an interference approach with repetitive transcranial magnetic stimulation (rTMS) and ERPs as indices of timing mechanisms. Methods Nine healthy volunteers performed a temporal discrimination task in which they had to decide whether the time interval between two tones was shorter (800 ms), equal to, or longer (1200 ms) than a previously listened standard interval (1000 ms) and press different buttons accordingly. The task was performed at the baseline and immediately after a 15-min-long train of focal 1-Hz rTMS delivered to supplementary motor area, right posterior parietal cortex, right superior temporal gyrus, or Oz (control area). Accuracy and reaction times and ERPs during (contingent negative variation, CNV) and after the end of the comparison interval were analyzed. Results At the baseline, CNV was modulated by the interval duration and the analysis of the ERP evoked after the end of the comparison interval showed that the amplitude of the positive peak emerging approximately after 200 ms was higher for ‘Long’ compared to ‘Short’ intervals, whereas amplitude for ‘Equal’ was intermediate. RTMS interference had no significant effect on behavioural performance or ERP components. Conclusion These data may suggest that these cortical areas are less crucially involved than other brain regions (e.g. sub-cortical or cerebellar areas) in the neural mechanisms processing basic temporal information like interval duration.