Nathalie George | Sorbonne University (original) (raw)

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Papers by Nathalie George

Recently, the neuroscience field took a particular interest in the use of a neuroimaging techniqu... more Recently, the neuroscience field took a particular interest in the use of a neuroimaging technique called ‘hyperscanning’. This new technique consists in the simultaneous recording of the hemodynamic or neuroelectric activities of multiple subjects. Behind this small technical step lays a giant methodological leap. Groundbreaking insight in the understanding of social cognition shall be achieved if the right paradigms are implemented. A growing number of studies demonstrate the potential of this recent technique. In this paper, we will focus on current issues and future perspectives of brain studies using hyperscanning. We will also add to this review two studies initiated by Line Garnero. These studies will illustrate the promising possibilities offered by hyperscanning through two different key phenomena pertaining to social interaction: gesture imitation and joint attention.

Neurophysiologie Clinique/Clinical Neurophysiology, 2008

The processing of upright, inverted and contrast-reversed faces was investigated using MEG.

Age-related changes in famous face incongruity detection were examined in middle-aged (mean ϭ 50.... more Age-related changes in famous face incongruity detection were examined in middle-aged (mean ϭ 50.6) and young (mean ϭ 24.8) subjects. Behavioral and ERP responses were recorded while subjects, after a presentation of a ''prime face'' (a famous person with the eyes masked), had to decide whether the following ''test face'' was completed with its authentic eyes (congruent) or with other eyes (incongruent). The principal effects of advancing age were (1) behavioral difficulties in discriminating between incongruent and congruent faces;

Social cognitive and affective neuroscience, Jan 28, 2015

Gaze direction, a cue of both social and spatial attention, is known to modulate early neural res... more Gaze direction, a cue of both social and spatial attention, is known to modulate early neural responses to faces e.g. N170. However, findings in the literature have been inconsistent, likely reflecting differences in stimulus characteristics and task requirements. Here, we investigated the effect of task on neural responses to dynamic gaze changes: away and toward transition (resulting or not in eye contact). Subjects performed, in random order, social (away/toward them) and non-social (left/right) judgment tasks on these stimuli. Overall, in the non-social task, results showed a larger N170 to gaze aversion than gaze motion toward the observer. In the social task, however, this difference was no longer present in the right hemisphere, likely reflecting an enhanced N170 to gaze motion toward the observer. Our behavioral and ERP data indicate that performing social judgments enhances saliency of gaze motion toward the observer, even those that did not result in gaze contact. These da...

Many functional magnetic resonance imaging studies have explored the neural correlates of social ... more Many functional magnetic resonance imaging studies have explored the neural correlates of social pain that results from social threat, exclusion, rejection, loss or negative evaluation. Although activations have consistently been reported within the anterior cingulate cortex (ACC), it remains unclear which ACC subdivision is particularly involved. To provide a quantitative estimation of the specific involvement of ACC subdivisions in social pain, we conducted a voxel-based meta-analysis. The literature search identified 46 articles that included 940 subjects, the majority of which used the cyberball task. Significant likelihoods of activation were found in both the ventral and dorsal ACC for both social pain elicitation and self-reported distress during social pain. Self-reported distress involved more specifically the subgenual and pregenual ACC than social pain-related contrasts. The cyberball task involved the anterior midcingulate cortex to a lesser extent than other experimental tasks. During social pain, children exhibited subgenual activations to a greater extent than adults. Finally, the ventro-dorsal gradient of ACC activations in cyberball studies was related to the length of exclusion phases. The present meta-analysis contributes to a better understanding of the role of ACC subdivisions in social pain, and it could be of particular importance for guiding future studies of social pain and its neural underpinnings.

NeuroImage, 2011

Inferring someone's personality from his or her photograph is a pervasive and automatic behavior ... more Inferring someone's personality from his or her photograph is a pervasive and automatic behavior that takes place even if no reliable information about one's character can be derived solely from facial features. This illustrates nicely the idea that perception is not a passive process, but rather an active combination of current sensory inputs with endogenous knowledge derived from prior experience. To understand how and when neural responses to faces can be modulated by prior experience, we recorded magneto-encephalographic (MEG) responses to new faces, before and after subjects were exposed for a short period of 15-20 min to an experimentally induced association between a facial feature (inter-eye distance) and a response (personality judgment). In spite of the absence of any observable response bias following such a short reinforcement phase, our experimental manipulation influenced neural responses to faces as early as 60-85 ms. Source localization of magneto-encephalographic signals, confirmed by intracranial recordings, suggests that prior experience modulates early neural processing along two initially independent neural routes, one initiated in an anterior system that includes the orbitofrontal cortex and the temporal poles, and the second one involving face-sensitive regions in the ventral visual pathway. The two routes are both active as early as 60 ms but engage in reciprocal interactions only later, between 135 and 160 ms. These experimental findings support recent models assuming the existence of a fast anterior pathway activated in parallel with the ventral visual system which would link prior experience with current sensory inputs.

Frontiers in Human Neuroscience, 2008

Annales Medico-psychologiques - ANN MEDICO-PSYCHOL, 2011

Emotions comprise a somatic and a psychological dimension. Indeed, they are both behavioural resp... more Emotions comprise a somatic and a psychological dimension. Indeed, they are both behavioural responses to internal or external stimuli and subjective experiences or feelings. Emotional perception can be defined as the detection and the appraisal of the emotional value of encountered stimuli. Attention capture and perceptual amplification are two important properties of emotional perception, which can result in enhanced conscious perception and increased processing of emotional stimuli. It has been proposed that amygdala plays a central role in the early detection of emotional stimuli. This paper presents the evidence accumulated in support of this proposal. In particular, recent studies showing emotional modulation of early brain responses (C1 and P1) to visual stimuli with electro- and magneto-encephalography (EEG and MEG) are reviewed.

Trends in Cognitive Sciences - TRENDS COGN SCI, 1998

PLoS ONE, 2013

Background: Amygdala is a key brain region for face perception. While the role of amygdala in the... more Background: Amygdala is a key brain region for face perception. While the role of amygdala in the perception of facial emotion and gaze has been extensively highlighted with fMRI, the unfolding in time of amydgala responses to emotional versus neutral faces with different gaze directions is scarcely known.

Neuropsychologia, 2011

Although the nature of the relationship between attention and awareness is actively debated, the ... more Although the nature of the relationship between attention and awareness is actively debated, the possibility that different forms of attention might interact differently with awareness has never been directly tested. We examine here whether voluntary and involuntary spatial attentions, two forms of attention that were distinguished by manipulating the predictability of central arrow cues, interact in the same way with visual awareness. Conscious perception was enhanced by both voluntary and involuntary attentions, and to a similar extent, suggesting volition may not be an essential feature for awareness. However, the influence of attention was dependent on the awareness of the target stimulus: Voluntary attention shortened reaction times and improved discrimination accuracy of cued relative to uncued stimuli, but only when the stimuli were consciously perceived. Involuntary attention shortened reaction times for cued relative to uncued target stimuli, but only when the stimuli were not consciously perceived. Our results imply that the nature of the relationship between attention and awareness is not a simple one but depends on the type of attention involved. More specifically, our results suggest that the aware or unaware status of the stimulus could determine whether attentional facilitation is driven by voluntary or involuntary mechanisms, a proposal that goes in the opposite direction of the classical view that attention controls awareness. Because voluntary attentional benefits were observed in aware trials but involuntary attentional benefits were observed in unaware trials only, our results also argue against the idea that attentional effects on conscious and unconscious processing are fundamentally of the same nature.

IRBM, 2011

Combining excellent temporal resolution with accurate source localization is a challenge for brai... more Combining excellent temporal resolution with accurate source localization is a challenge for brain imaging studies in humans. In this domain, showing evidence for the contribution of deep brain structures to magneto-encephalographic (MEG) signal may represent an important step. The amygdala, is an example of such structure that is essential for social cognition and emotional processes. To date, MEG studies have been mainly focused on cortical activities. Under the impulsion of Line Garnero, we tackled the challenge of detecting the activation of deep brain structures with non-invasive electromagnetic brain imaging methods and developed a new method to localize amygdala sources. Here, we first review amygdala structural and histological properties that argue in favour of the detection of its activity with MEG. Then we present a simulation study of amygdala contribution to MEG signal. This study was based on an original anatomical segmentation technique, which allowed distributing sources within the amygdala volume of each subject. Finally, we present preliminary data from a face perception experiment where amygdala activity was examined with this new distributed source imaging method.

Cognition, 2010

Current models in social neuroscience advance that eye contact may automatically recruit cognitiv... more Current models in social neuroscience advance that eye contact may automatically recruit cognitive resources. Here, we directly tested this hypothesis by evaluating the distracting strength of eye contact on concurrent visual processing in the well-known Stroop's paradigm. As expected, participants showed stronger Stroop interference under concomitant eye contact as compared to closed eyes. Two control experiments allowed ruling out low-level account of this effect as well as non-specific effect of the presence of open eyes. This suggests that refraining from processing eye contact is actually as difficult as refraining from word reading in the Stroop task. Crucially, the eye contact effect was obtained while gaze was not under the direct focus of attention and the participants were faced with another powerful distracter (the incongruent word) in the task at hand. Thus, there is a cost of being watched even in circumstances where the processing of direct gaze is strongly disfavored. The present results emphasize the crucial status of eye contact in human cognition.