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

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.

Three sequential brain activations encode mental transformations of upright and inverted human bodies: a high resolution evoked potential study

Olaf Blanke

Human bodies provide a particularly rich source of visual information. Whereas most previous studies have focused on the neural mechanisms during the perception and recognition of human bodies, the aim of the present study was to investigate the time course and location of brain activation during mental imagery of human bodies. When participants were asked to imagine themselves in the position of a visually presented human body as seen from many different angles and at two orientations (upright or inverted), their reaction times were faster for upright as compared to inverted bodies and correlated differently with the tested angles. These behavioral effects were also reflected in brain activation patterns, but only during the time period from 220 to 490 ms after stimulus onset. Evoked potential mapping and electrical neuroimaging revealed three distinct and sequential steps of processing related to mental body transformation: (1) an early activation in temporo-occipital and temporo-parietal cortex (220-360 ms) that does not distinguish between upright and inverted bodies, but closely reflects the effort of mental transformation, followed (2) by an activation in temporo-occipital and medial parieto-occipital cortex (350-460 ms) that encodes mental transformation for upright bodies, and (3) a later activation in temporo-occipital and prefrontal cortex (390-490 ms) that encodes mental transformation for inverted bodies. These data suggest that the mental transformation of human bodies is not a single process but a sequence of temporally distinct processing steps, where each step reflects a distinct aspect of the transformation process that consists of activations in a network of posterior brain areas including extrastriate cortex, temporo-parietal cortex, and medial parieto-occipital cortex, as well as an anterior brain region in prefrontal cortex.

Elsevier2009

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

Learning, Stress and the Role of Personality Profiles in Rats

Basira Salehi, Maria del Carmen Sandi Perez

Stress has been shown to modulate many aspects of physiology and behavior. In particular, substantial work has confirmed that stress is a strong modulator of learning and memory processes. It is more than a century that Yerkes and Dodson have shown that relationship between stress intensity and memory function follows an inverted-U-shaped curve; memory increases with stress to an optimal point, above or below which memory decreases. Despite the great popularity of the Yerkes-Dodson law, the validity of the law has been criticized due to significant methodological problems in the study performed by Yerkes and Dodson (1908) and their data being judged insufficient to substantiate conclusions, among other reasons. Moreover the existing evidence has not yet illustrated this phenomenon under the same experimental conditions for relational learning tasks. On the other hand, stress is not the only factor that modulates cognitive abilities. Different types of learning and memory might be affected by other factors such as individual differences in personality. While the relationship between personality and learning has been studied in human, animal studies addressed to understanding the relationship between personality and learning have been rare. In addition, exposure to stress during pregnancy can have deleterious emotional effects on women. However, the mechanisms underlying these emotional effects are not well understood, and the development of suitable animal models for stress-induced depression in females still remains scarce. The goal of this Thesis was to investigate how stress affects cognitive and emotional processes in different animal models, and to explore the importance of individual differences in the mediation of stress effects. On a first study, we investigated the relationship between stress intensity and memory function. For this purpose cognitive abilities of rats to learn a radial arm water maze were assessed under different stress intensities, using behavioural and endocrine approaches. Our results confirm, for the first time, the existence of an inverted-U-shape memory function according to stressor intensity during the early learning and memory phases in a hippocampus-dependent task. Furthermore, we present evidence that these stress effects are not shown uniformly by all individuals; rather, performance at either the high or the low stress intensities is differentially affected in individuals with different personality-like profiles. In a second study, we investigated whether different personality traits in the Wistar outbred strain of rats were associated with performance in specific types of learning and memory tasks that have been reported to depend on specific brain areas, such as the amygdala, hippocampus and prefrontal cortex (PFC). Using a wide variety of behavioral tests, we identified three personality factors: anxiety, exploration and locomotion. According to our results, the locomotion trait displayed no correlation with learning and memory. However curiosity trait predicted extinction of fear memories and spatial reversal learning, and the anxiety traits was related to extinction of fear. These results suggest that behavioral traits, anxiety and curiosity, might be linked to the functioning of specific brain areas (i.e. amygdala and PFC). Our findings are consistent with recent human studies showing that certain personality traits can predict academic achievement and point out the importance of constructing learning environments that could optimize individual strengths. In a third study, we used a model of stress during pregnancy in an attempt to mirror more closely than other experimental approaches based mainly on movement restraint procedures the human condition where stress is often persistently imposed by a male aggressive partner. For that purpose we used aggressive male rats that cohabitated with (and therefore can be considered a stressor) female rats during their pregnancy and, then, characterized the behaviour of these females after weaning. Similar to effects reported in humans, mother rats displayed anxiety-like and depressive-like behaviours, with the females presenting a high anxiety trait being the more vulnerable to the deleterious effects resulting from exposure to the aggressive male. These results propose an interesting animal model to study the effect of stress during pregnancy. Taken together, our results reinforce the view that stress has a strong impact on cognitive function and emotion. They also stress the importance of taking into account individual differences to characterize individuals with different vulnerability to be affected in both cognitive and emotional domain by exposure to stress. Our approach is novel and original in that it takes into account several behavioural (personality-like) traits simultaneously and shows the importance of different traits for different aspects of the relationship between stress, emotion and cognition. The approaches and findings provide valuable models to address the neurobiological mechanisms underlying stress effects on behavior.