Michel-Pierre Coll

The neural network of motor imagery: An ALE meta-analysis

Motor imagery (MI) or the mental simulation of action is now increasingly being studied using neuroimaging techniques such as positron emission tomography and functional magnetic resonance imaging. The booming interest in capturing the neural underpinning of MI has provided a large amount of data which until now have never been quantitatively summarized. The aim of this activation likelihood estimation (ALE) meta-analysis was to provide a map of the brain structures involved in MI. Combining the data from 75 papers revealed that MI consistently recruits a large fronto-parietal network in addition to subcortical and cerebellar regions. Although the primary motor cortex was not shown to be consistently activated, the MI network includes several regions which are known to play a role during actual motor execution. The body part involved in the movements, the modality of MI and the nature of the MI tasks used all seem to influence the consistency of activation within the general MI network. In addition to providing the first quantitative cortical map of MI, we highlight methodological issues that should be addressed in future research.

Cross-modal repetition effects in the mu rhythm indicate tactile mirroring during action observation.

Similar cortical activations during the experience and observation of touch suggest the presence of a tactile mirroring system. However, the specificity of observation-related activity - i.e., whether observation excites the same representations as experience of that specific tactile stimulation - is still to be established. Furthermore, central mu rhythms are attenuated during the experience and observation of touch, and also during action observation and execution, making it unclear whether they index processing of predominantly tactile or motor features of observed actions. The present study used an electroencephalography (EEG) cross-modal repetition paradigm to assess the relative tactile and motor specificity of mu attenuation during action observation. Two experiments were carried out during which participants executed and observed actions in alternation, and the repetition of either tactile or motor features of the actions were manipulated. The mu signal over central electrodes varied as a function of tactile repetition, consistent with the claim of a tactile mirroring system and its reflection in the mu signal. Of note was the fact that mu attenuation was sensitive only to manipulation of tactile - not motor - properties of actions, suggesting that caution should be employed when interpreting mu effects during action observation as reflective of motor mirroring.

Are we really measuring empathy? Proposal for a new measurement framework

HighlightsEmpathy is currently defined as sharing the state of another.This definition conflates the identification and the sharing of anothers state.Describing change or impairment in empathy therefore lacks specificity.We show how this can be problematic for popular paradigms in social neuroscience.And propose an alternative measurement framework to resolve. Abstract Empathy – currently defined as the sharing of another’s affective state – has been the focus of much psychological and neuroscientific research in the last decade, much of which has been focused on ascertaining the empathic ability of individuals with various clinical conditions. However, most of this work tends to overlook the fact that empathy is the result of a complex process requiring a number of intermediate processing steps. It is therefore the case that describing an individual or group as ‘lacking empathy’ lacks specificity. We argue for an alternative measurement framework, in which we explain variance in empathic response in terms of individual differences in the ability to identify another’s emotional state (‘emotion identification’), and the degree to which identification of another’s state causes a corresponding state in the self (‘affect sharing’). We describe how existing empathy paradigms need to be modified in order to fit within this measurement framework, and illustrate the utility of this approach with reference to examples from both cognitive neuroscience and clinical psychology.

Repeated exposure to vicarious pain alters electrocortical processing of pain expressions.

Repeated exposure to others in pain has been shown to bias vicarious pain perception, but the neural correlates of this effect are currently not known. The current study therefore aimed at measuring electrocortical responses to facial expressions of pain following exposure to expressions of pain. To this end, a between-subject design was adopted. Participants in the Exposure group were exposed to facial expressions of intense pain, while the participants in the Control group were exposed to neutral expressions before performing the same pain detection task. As in previous studies, participants in the Exposure group showed a significantly more conservative bias when judging facial expressions pain, meaning that they were less inclined to judge moderate pain expressions as painful compared to participants in the Control group. Event-related potential analyses in response to pain or neutral expressions indicated that this effect was related to a relative decrease in the central late positive potential responses to pain expressions. Furthermore, while the early N170 response was not influenced by repeated exposure to pain expressions, the P100 component showed an adaptation effect in the Control group only. These results suggest that repeated exposure to vicarious pain do not influence early event-related potential responses to pain expressions but decreases the late central positive potential. These results are discussed in terms of changes in the perceived saliency of pain expressions following repeated exposure.

Repeated exposure to others’ pain reduces vicarious pain intensity estimation

Pain perception in others can be influenced by different contextual factors. In clinical settings, the repeated exposure to others’ pain has been proposed as a factor that could explain underestimation of patients’ pain by health care providers. Previous research supported this idea by showing that repeated exposure to persons in pain biases the subsequent willingness to impute pain in others. However, it remains unclear if the effect of repeated exposure on the detection of pain extends to deliberate pain estimation of stimuli presented for a longer period.

Knowledge of resting heart rate mediates the relationship between intelligence and the heartbeat counting task

Evidence suggests that intelligence is positively associated with performance on the heartbeat counting task (HCT). The HCT is often employed as measure of interoception - the ability to perceive the internal state of ones body - however its use remains controversial as performance on the HCT is strongly influenced by knowledge of resting heart rate. This raises the possibility that heart rate knowledge may mediate the previously-observed association between intelligence and HCT performance. Study One demonstrates an association between intelligence and HCT performance (N = 94), and Study Two demonstrates that this relationship is mediated by knowledge of the average resting heart rate (N = 134). These data underscore the need to account for the influence of prior knowledge and beliefs when examining individual differences in cardiac interoceptive accuracy using the HCT.

Crossmodal Classification of Mu Rhythm Activity during Action Observation and Execution Suggests Specificity to Somatosensory Features of Actions

The alpha mu rhythm (8–13 Hz) has been considered to reflect mirror neuron activity because it is attenuated by both action observation and action execution. The putative link between mirror neuron system activity and the mu rhythm has been used to study the involvement of the mirror system in a wide range of socio-cognitive processes and clinical disorders. However, previous research has failed to convincingly demonstrate the specificity of the mu rhythm, meaning that it is unclear whether the mu rhythm reflects mirror neuron activity. It also remains unclear whether mu rhythm suppression during action observation reflects the processing of motor or tactile information. In an attempt to assess the validity of the mu rhythm as a measure of mirror neuron activity, we used crossmodal pattern classification to assess the specificity of EEG mu rhythm response to action varying in terms of action type (whole-hand or precision grip), concurrent tactile stimulation (stimulation or no stimulation), or object use (transitive or intransitive actions) in 20 human participants. The main results reveal that above-chance crossmodal classification of mu rhythm activity was obtained in the central channels for tactile stimulation and action transitivity but not for action type. Furthermore, traditional univariate analyses applied to the same data were insensitive to differences between conditions. By calling into question the relationship between mirror system activity and the mu rhythm, these results have important implications for the use and interpretation of mu rhythm activity. SIGNIFICANCE STATEMENT The central alpha mu rhythm oscillation is a widely used measure of the human mirror neuron system that has been used to make important claims concerning cognitive functioning in health and in disease. Here, we used a novel multivariate analytical approach to show that crossmodal EEG mu rhythm responses primarily index the somatosensory features of actions, suggesting that the mu rhythm is not a valid measure of mirror neuron activity. Results may lead to the revision of the conclusions of many previous studies using this measure, and to the transition toward a theory of mu rhythm function that is more consistent with current models of sensory processing in the self and in others.

Selective Reporting, Analytical Flexibility and Multiple Comparisons in ERP Research: The case of Pain Empathy

Empathy has received considerable attention from the field of cognitive and social neuroscience. A significant portion of these studies used the event-related potential (ERP) technique to study the mechanisms of empathy for pain in others in different conditions and clinical populations. These show that specific ERP components measured during the observation of pain in others are modulated by several factors and altered in clinical populations. However, issues present in this literature such as analytical flexibility and lack of type 1 error control raise doubts regarding the validity and reliability of these conclusions. The current study compiled the results and methodological characteristics of 40 studies using ERP to study empathy of pain in others. The results of the meta-analysis suggest that the centro-parietal P3 and late positive potential component are sensitive to the observation of pain in others, while the early N1 and N2 components are not reliably associated with vicarious pain observation. The review of the methodological characteristics shows that the presence of selective reporting, analytical flexibility and lack of type 1 error control compromise the interpretation of these results. The implication of these results for the study of empathy and potential solutions to improve future investigations are discussed.Empathy has received considerable attention from the field of cognitive and social neuroscience. A significant portion of these studies used the event-related potential (ERP) technique to study the mechanisms of empathy for pain in others in different conditions and clinical populations. These show that specific ERP components measured during the observation of pain in others are modulated by several factors and altered in clinical populations. However, issues present in this literature such as analytical flexibility and lack of type 1 error control raise doubts regarding the validity and reliability of these conclusions. The current study compiled the results and methodological characteristics of 36 studies using ERP to study empathy of pain in others. The results of the meta-analysis suggest that the frontal N2 and the centro-parietal P3 and late positive potential component are sensitive to the observation of pain in others. However, the review of the methodological characteristics shows that the presence of selective reporting, analytical flexibility and lack of type 1 error control compromise the interpretation of these results. These issues and potential solutions to improve future investigations of pain empathy using ERP are discussed.

Meta-analysis of ERP investigations of pain empathy underlines methodological issues in ERP research

Abstract Empathy has received considerable attention from the field of cognitive and social neuroscience. A significant portion of these studies used the event‐related potential (ERP) technique to study the mechanisms of empathy for pain in others in different conditions and clinical populations. These show that specific ERP components measured during the observation of pain in others are modulated by several factors and altered in clinical populations. However, issues present in this literature such as analytical flexibility and lack of type 1 error control raise doubts regarding the validity and reliability of these conclusions. The current study compiled the results and methodological characteristics of 40 studies using ERP to study empathy of pain in others. The results of the meta‐analysis suggest that the centro‐parietal P3 and late positive potential component are sensitive to the observation of pain in others, while the early N1 and N2 components are not reliably associated with vicarious pain observation. The review of the methodological characteristics shows that the presence of selective reporting, analytical flexibility and lack of type 1 error control compromise the interpretation of these results. The implication of these results for the study of empathy and potential solutions to improve future investigations are discussed.