EEG-MEG evidence for early differential repetition effects for fearful, happy and neutral faces

To deter-mine how emotional information modulates subsequent traces for repeated stimuli, we combined simultaneous electro-encephalography (EEG) and magneto-encephalography (MEG) measures during long-lag incidental repetition of fearful, happy, and neutral faces. Repetition effects were modulated by facial expression in three different time windows, starting as early as 40-50 ms in both EEG and MEG, then arising at the time of the N170/M170, and finally between 280-320 ms in MEG only. The very early repetition effect, observed at 40-50 ins over occipito-temporo-parietal regions, showed a different MEG topography according to the facial expression. This differential response to fearful, happy and neutral faces suggests the existence of very early discriminative visual processing of expressive faces, possibly based on the low-level physical features typical of different emotions. The N170 and M170 face-selective components both showed repetition enhancement selective to neutral faces, with greater amplitude for emotional than neutral faces on the first but not the second presentation. These differential repetition effects may reflect valence acquisition for the neutral faces due to repetition, and suggest a combined influence of emotion- and experience-related factors on the early stage of face encoding. Finally, later repetition effects consisted in enhanced M300 (MEG) between 280 and 320 ms for fearful relative to happy and neutral faces that occurred on the first presentation, but levelled out on the second presentation. This effect may correspond to the higher arousing value of fearful stimuli that might habituate with repetition. Our results reveal that multiple stages of face processing are affected by the repetition of emotional information. (C) 2008 Elsevier B.V. All rights reserved.

The Cognitive And Neural Time Course Of Empathy And Sympathy: An Electrical Neuroimaging Study On Self-Other Interaction

Olaf Blanke, Manuel Mercier

Although extensively investigated in sociocognitive neuroscience, empathy is difficult to study. The first difficulty originates in its multifaceted nature. According to the multidimensional model, empathy combines emotional, automatic (simulation), cognitive (mentalizing) and regulatory (executive functions) processes. Substantial functional magnetic resonance imaging (fMRI) data demonstrated that co-activations in the mirror neuron system (MNS) and mentalizing network (MENT) sustain this co-recruitment of so-called first-and second-person-like processes. Because of the poor temporal resolution of fMRI techniques, we currently lack evidence about the precise timing of the MNS-MENT combination. An important challenge is, thus, to disentangle how MNS and MENT dynamically work together along time in empathy. Moreover, the role of the executive functions in the MNS-MENT combination time course is still unknown. Second, empathy - feeling into - is closely related to sympathy - feeling with - and both phenomena are often conflated in experimental studies on intersubjectivity. In this electrical neuroimaging (EEG) pilot-study, we tested whether the egocentered vs. heterocentered visuo-spatial mechanisms respectively associated with sympathy and empathy differentially modulate the dynamic combination of the MNS-MENT activations in their respective neural time course. For that, we employed our newly developed behavioral paradigm assessing the visuospatial - but not emotional - features of empathy and sympathy. Using a data-driven approach, we report that empathy and sympathy are underlied by sequential activations in the MNS from the insula to the inferior frontal gyrus (IFG) between 63 ms and 424 ms. However, at 333-424 ms, empathy triggered greater co-activations in the right IFG and dorsolateral prefrontal cortex (dlPFC) (executive functions). Linking together our present and prior (Thirioux et al., 2010) findings from the same dataset, we suggest that this greater recruitment of the right dlPFC monitors the shift from egocentered and first-person-like mechanisms in the MNS to heterocentered and second-person-like mechanisms in the left temporo-parietal junction within the MENT, i.e., reflecting the onset of perspective-change processes in the neural time course of empathy. Contrasting with sympathy, this recruitment of the executive functions could modulate the output end of the mirroring processing in the premotor and sensorimotor cortices. (C) 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

Pergamon-Elsevier Science Ltd2014

The electrophysiological effects of the serotonin 1A receptor agonist buspirone in emotional face processing

Fosco Bernasconi

Emotional face processing is critically modulated by the serotonergic system, and serotonin (5-HT) receptor agonists impair emotional face processing. However, the specific contribution of the 5-HT1A receptor remains poorly understood. Here we investigated the spatiotemporal brain mechanisms underpinning the modulation of emotional face processing induced by buspirone, a partial 5-HT1A receptor agonist. In a psychophysical discrimination of emotional faces task, we observed that the discrimination fearful versus neutral faces were reduced, but not happy versus neutral faces. Electrical neuroimaging analyses were applied to visual evoked potentials elicited by emotional face images, after placebo and buspirone administration. Buspirone modulated response strength (i.e., global field power) in the interval 230-248 ms after stimulus onset. Distributed source estimation over this time interval revealed that buspirone decreased the neural activity in the right dorsolateral prefrontal cortex that was evoked by fearful faces. These results indicate temporal and valence-specific effects of buspirone on the neuronal correlates of emotional face processing. Furthermore, the reduced neural activity in the dorsolateral prefrontal cortex in response to fearful faces suggests a reduced attention to fearful faces. Collectively, these findings provide new insights into the role of 5-HT1A receptors in emotional face processing and have implications for affective disorders that are characterized by an increased attention to negative stimuli. (C) 2015 Elsevier B.V. and ECNP. All rights reserved.

Elsevier Science Bv2015

The Cognitive And Neural Time Course Of Empathy And Sympathy: An Electrical Neuroimaging Study On Self-Other Interaction

Olaf Blanke, Manuel Mercier

Pergamon-Elsevier Science Ltd2014