Bruno Wicker

Both of Us Disgusted in My Insula: The Common Neural Basis of Seeing and Feeling Disgust

What neural mechanism underlies the capacity to understand the emotions of others? Does this mechanism involve brain areas normally involved in experiencing the same emotion? We performed an fMRI study in which participants inhaled odorants producing a strong feeling of disgust. The same participants observed video clips showing the emotional facial expression of disgust. Observing such faces and feeling disgust activated the same sites in the anterior insula and to a lesser extent in the anterior cingulate cortex. Thus, as observing hand actions activates the observers motor representation of that action, observing an emotion activates the neural representation of that emotion. This finding provides a unifying mechanism for understanding the behaviors of others.

The anthropomorphic brain: the mirror neuron system responds to human and robotic actions.

In humans and monkeys the mirror neuron system transforms seen actions into our inner representation of these actions. Here we asked if this system responds also if we see an industrial robot perform similar actions. We localised the motor areas involved in the execution of hand actions, presented the same subjects blocks of movies of humans or robots perform a variety of actions. The mirror system was activated strongly by the sight of both human and robotic actions, with no significant differences between these two agents. Finally we observed that seeing a robot perform a single action repeatedly within a block failed to activate the mirror system. This latter finding suggests that previous studies may have failed to find mirror activations to robotic actions because of the repetitiveness of the presented actions. Our findings suggest that the mirror neuron system could contribute to the understanding of a wider range of actions than previously assumed, and that the goal of an action might be more important for mirror activations than the way in which the action is performed.

Brain regions involved in the perception of gaze: a PET study.

Mutual gaze may be described as a psychological process during which two persons have the feeling of a brief link between their two minds. In the monkey, specific cell assemblies in the superior temporal cortex of the brain are responsive to gaze. This suggests that the brain may have evolved mechanisms for interpreting direct eye contact. These mechanisms could depend on the activation of specific brain regions. Positron emission tomography was used to measure activity in brain regions in healthy volunteers while they were looking at faces featuring, respectively, eye contact, averted gaze, or no gaze. As expected a region known to be involved in face processing was found to be activated in the ventral occipito-temporal region, especially in the right hemisphere. Averted gaze and mutual gaze triggered blood flow responses in similar areas which were different from those involved in face processing. These areas included the occipital part of the fusiform gyrus, the right parietal lobule, the right inferior temporal gyrus, and the middle temporal gyrus in both hemispheres. These results are consistent with the hypothesis that perception of eyes regardless of the direction of the gaze is subserved by a distributed network. However, no conclusive evidence was found for specific area(s) devoted to mutual gaze processing.

Being the target of another's emotion: a PET study

The eye region and gaze behaviour are known to play a major role in conveying information about direction of attention and emotional dispositions. Positron emission tomography scanning was used to explore the cerebral structures involved while subjects were asked to attribute hostile or friendly intentions to video-taped actors who directed attention towards or away from the subjects. As expected, a number of brain regions known to be involved in emotion processing was found activated when subjects had to attribute an emotion regardless of gaze direction. In addition, results indicate that gaze direction has an impact on the brain regions recruited to interpret emotions. The anterior region of the superior temporal gyrus (STG) was selectively activated during analysis of emotions through eye contact. This result provides neurophysiological evidence for privileged processing when an individual becomes personally involved as the object of anothers emotions.

A challenging, unpredictable world for people with autism spectrum disorder.

Autism is a pervasive neurodevelopmental disorder characterized by impairment of communication and social interaction, as well as by high levels of repetitive and ritualistic behaviours. This last dimension results in major difficulties in daily life: clinical reports of individuals with Autism Spectrum Disorder (ASD) show that they present tantrums as a response to change, or restricted interests and repetitive behaviours in order to prevent or minimize change. Such a crucial need to maintain sameness suggests substantial differences in how the ASD brain predicts the environment, and this might have a fundamental role in the deficit revealed in the highly unpredictable social world. Several lines of evidence indicating difficulties in generating or using predictions in ASD due to atypical information processing will be presented in this review. For instance, several studies have revealed that people with ASD demonstrate a unique profile of cognitive abilities, with strategies that depend to an abnormally large extent on sensory systems, at the expense of more integrative processing requiring an awareness of contextual subtleties necessary for prediction. At a more elementary level, patients with autism manifest unusual processing of unpredictable events, which might be rooted in a basic difference in how the brain orients to changing, novel sensory stimuli. This review presents results from ERPs and fMRI studies illustrating the psychophysiological mechanisms and neural bases underlying such phenomena in ASD. We propose that such dysfunction in the ability to build flexible prediction in ASD may originate from impaired top-down influence over a variety of sensory and higher level information processing, a physiopathological hypothesis which dovetails with the cortical under connectivity current theory.

Electrodermal reactivity to emotion processing in adults with autistic spectrum disorders

Although alterations of emotion processing are recognized as a core component of autism, the level at which alterations occur is still debated. Discrepant results suggest that overt assessment of emotion processing is not appropriate. In this study, skin conductance response (SCR) was used to examine covert emotional processes. Both behavioural responses and SCRs of 16 adults with an autistic spectrum disorder (ASD) were compared to those of 16 typical matched adults. Participants had to judge emotional facial expressions, the age of faces or the direction of a moving object. Although behavioural performance was similar in the two populations, individuals with an ASD exhibited lower SCRs than controls in the emotional judgement task. This suggests that such individuals may rely on different strategies due to altered autonomic processing. Furthermore, failure to produce normal physiological reactions to emotional faces may be related to social impairments in individuals with an ASD.

Disrupting the right prefrontal cortex alters moral judgement

Humans daily face social situations involving conflicts between competing moral decision. Despite a substantial amount of studies published over the past 10 years, the respective role of emotions and reason, their possible interaction, and their behavioural expression during moral evaluation remains an unresolved issue. A dualistic approach to moral evaluation proposes that the right dorsolateral prefrontal cortex (rDLPFc) controls emotional impulses. However, recent findings raise the possibility that the right DLPFc processes emotional information during moral decision making. We used repetitive transcranial magnetic stimulation (rTMS) to transiently disrupt rDLPFc activity before measuring decision making in the context of moral dilemmas. Results reveal an increase of the probability of utilitarian responses during objective evaluation of moral dilemmas in the rTMS group (compared to a SHAM one). This suggests that the right DLPFc function not only participates to a rational cognitive control process, but also integrates emotions generated by contextual information appraisal, which are decisive for response selection in moral judgements.

Discrepancies between Judgment and Choice of Action in Moral Dilemmas

Everyone has experienced the potential discrepancy between what one judges as morally acceptable and what one actually does when a choice between alternative behaviors is to be made. The present study explores empirically whether judgment and choice of action differ when people make decisions on dilemmas involving moral issues. Two hundred and forty participants evaluated 24 moral and non-moral dilemmas either by judging (“Is it acceptable to…”) or reporting the choice of action they would make (“Would you do…”). We also investigated the influence of varying the number of people benefiting from the decision and the closeness of relationship of the decision maker with the potential victim on these two types of decision. Variations in the number of beneficiaries from the decision did not influence judgment nor choice of action. By contrast, closeness of relationship with the victim had a greater influence on the choice of action than on judgment. This differentiation between evaluative judgments and choices of action argues in favor of each of them being supported by (at least partially) different psychological processes.

High levels of psychopathic traits alters moral choice but not moral judgment

Psychopathy is a personality disorder frequently associated with immoral behaviors. Previous behavioral studies on the influence of psychopathy on moral decision have yielded contradictory results, possibly because they focused either on judgment (abstract evaluation) or on choice of hypothetical action, two processes that may rely on different mechanisms. In this study, we explored the influence of the level of psychopathic traits on judgment and choice of hypothetical action during moral dilemma evaluation. A population of 102 students completed a questionnaire with ten moral dilemmas and nine non-moral dilemmas. The task included questions targeting both judgment (“Is it acceptable to … in order to …?”) and choice of hypothetical action (“Would you … in order to …?”). The level of psychopathic traits of each participant was evaluated with the Levenson Self-Report Psychopathy (LSRP) scale. Logistic regression fitted with the generalized estimating equations method analyses were conducted using responses to the judgment and choice tasks as the dependent variables and psychopathy scores as predictor. Results show that a high level of psychopathic traits, and more specifically those related to affective deficit, predicted a greater proportion of utilitarian responses for the choice but not for the judgment question. There was no first-order interaction between the level of psychopathic traits and other potential predictors. The relation between a high level of psychopathic traits and increased utilitarianism in choice of action but not in moral judgment may explain the contradictory results of previous studies where these two processes were not contrasted. It also gives further support to the hypothesis that choice of action endorsement and abstract judgment during moral dilemma evaluation are partially distinct neural and psychological processes. We propose that this distinction should be better taken into account in the evaluation of psychopathic behaviors.

Distinct patterns of functional brain connectivity correlate with objective performance and subjective beliefs

The degree of correspondence between objective performance and subjective beliefs varies widely across individuals. Here we demonstrate that functional brain network connectivity measured before exposure to a perceptual decision task covaries with individual objective (type-I performance) and subjective (type-II performance) accuracy. Increases in connectivity with type-II performance were observed in networks measured while participants directed attention inward (focus on respiration), but not in networks measured during states of neutral (resting state) or exogenous attention. Measures of type-I performance were less sensitive to the subjects’ specific attentional states from which the networks were derived. These results suggest the existence of functional brain networks indexing objective performance and accuracy of subjective beliefs distinctively expressed in a set of stable mental states.