Mirror Neuron System Activity Research Articles

Mu-Suppression Neurofeedback Training Targeting the Mirror Neuron System: A Pilot Study.

Neurofeedback training (NFT) is a promising adjuvant intervention method. The desynchronization of mu rhythm (8-13 Hz) in the electroencephalogram (EEG) over centro-parietal areas is known as a valid indicator of mirror neuron system (MNS) activation, which has been associated with social skills. Still, the effect of neurofeedback training on the MNS requires to be well investigated. The present study examined the possible impact of NFT with a mu suppression training protocol encompassing 15 NFT sessions (45 min each) on 16 healthy neurotypical participants. In separate pre- and post-training sessions, 64-channel EEG was recorded while participants (1) observed videos with various types of movements (including complex goal-directed hand movements and social interaction scenes) and (2) performed the "Reading the Mind in the Eyes Test" (RMET). EEG source reconstruction analysis revealed statistically significant mu suppression during hand movement observation across MNS-attributed fronto-parietal areas after NFT. The frequency analysis showed no significant mu suppression after NFT, despite the fact that numerical mu suppression appeared to be visible in a majority of participants during goal-directed hand movement observation. At the behavioral level, RMET accuracy scores did not suggest an effect of NFT on the ability to interpret subtle emotional expressions, although RMET response times were reduced after NFT. In conclusion, the present study exhibited preliminary and partial evidence that mu suppression NFT can induce mu suppression in MNS-attributed areas. More powerful experimental designs and longer training may be necessary to induce substantial and consistent mu suppression, particularly while observing social scenarios.

Functional features of the mirror neuron system during action observation and execution in patients with anxiety and depressive symptoms

The perception and comprehension of non-verbal information and body language in humans and higher primates are realized by the mirror neuron system (MNS). Anxiety and depressive symptoms may change social perception, which could manifest as functional changes in the MNS. In this paper, using the inverse electroencephalography (EEG) problem and rhythm suppression, we investigated spatial and frequency distortions of the MNS in 24 patients exhibiting depressive and anxiety symptoms and 23 controls. EEG was recorded during four motor tasks: action observation (where participants observed a hand gesture performed by a demonstrator), imagination, execution, and joint execution (simultaneous execution with the demonstrator). Mu suppression was employed across a wide frequency and spatial range to assess the level of MNS activity, while the sLORETA method was employed to localize the activity sources. The results indicate that the patients demonstrated task-selective mu suppression mainly during observation and joint execution in the frontal, central, and occipital areas of the cortex across a wide frequency range. In contrast, the controls demonstrated clear and pronounced mu rhythm suppression in the central regions of the brain in the upper-frequency range (10.5 – 13 Hz) during all mirroring tasks. These results suggest that patients with anxiety and depressive symptoms engage additional neural resources to complete social tasks, particularly involving auxiliary neural networks located in the frontal associative arrays and visual cortex.

Evidence of mirror therapy for recruitment of ipsilateral motor pathways in stroke recovery: A resting fMRI study

Mirror therapy (MT) has been proposed to promote motor recovery post-stroke through activation of mirror neuron system, recruitment of ipsilateral motor pathways, or/and increasing attention toward the affected limb. However, neuroimaging evidence for these mechanisms is still lacking. To uncover the underlying mechanisms, we designed a randomized controlled study and used a voxel-based whole-brain analysis of resting-state fMRI to explore the brain reorganizations induced by MT. Thirty-five stroke patients were randomized to an MT group (n ​= ​16) and a conventional therapy (CT) group (n ​= ​19) for a 4-week intervention. Before and after the intervention, the Fugl-Meyer Assessment Upper Limb subscale (FMA-UL) and resting-state fMRI were collected. A healthy cohort (n ​= ​16) was established for fMRI comparison. The changes in fractional amplitude of low-frequency fluctuation (fALFF) and seed-based functional connectivity were analyzed to investigate the impact of intervention. Results showed that greater FMA-UL improvement in the MT group was associated with the compensatory increase of fALFF in the contralesional precentral gyrus (M1) region and the re-establishment of functional connectivity between the bilateral M1 regions, which facilitate motor signals transmission via the ipsilateral motor pathways from the ipsilesional M1, contralesional M1, to the affected limb. A step-wise linear regression model revealed these two brain reorganization patterns collaboratively contributed to FMA-UL improvement. In conclusion, MT achieved motor rehabilitation primarily by recruitment of the ipsilateral motor pathways. Trial Registration Information: http://www.chictr.org.cn. Unique Identifier. ChiCTR-INR-17013644, submitted on December 2, 2017.

The role of mirror system in influencing the valence evaluation of words: a TMS study

The mirror neuron system (MNS) has been a captivating area of research since its discovery in macaque monkeys [1]. Researchers have established the role and presence of the human auditory mirror system in both empathy [2] and musical creativity [3]. As well, the mirror system allows to learn new behaviors by observation, facilitating knowledge acquisition and action understanding. In addition, research has indicated the influence of stimulus valence on the human MNS [4]. The human brain is sensitive to the positive valence of words, and this reactivity may vary with the strength of the valence compared to negative words. Additionally, it can perceive differences in valence for negative stimuli and words. However, what about emotional words that are auditory? Do these words’ valence, whether positive, negative, or neutral, impact auditory mirror neurons and cortical excitability? The study examines how auditory words of different valences affect the MNS and cortical activity. This novel approach uses auditory stimuli to examine the role of mirror neurons in neuromodulation through a transcranial magnetic stimulation (TMS) protocol, which has not been done in previous investigations. The results of this study suggest that both positive and negative words will induce greater excitability [4], as evidenced by motor evoked potentials. The results of this study will have broad applications. Firstly, it will offer a new contribution to the investigation of mirror neurons through TMS protocol. Secondly, inferences can be drawn and applied in the field of therapeutics, where language is used as a tool to mediate the process. In general, it will increase personal awareness of language in daily communication, leading to an enhanced communication process. Furthermore, the study’s findings imply the existence of auditory mirror neurons and their pivotal role in comprehending the emotional valence of different words, thereby influencing our feelings. This will advance our understanding of the human brain and empower us to make informed decisions. The study is being conducted with the HSE Automated system for non-invasive brain stimulation, which allows for simultaneous recording of brain activity and eye movement.

Autisme en Neurobiologie: Wat We (Niet) Weten

After decades of brain research on autism, the question is what insights this research has given into the neural mechanisms underlying autism symptomatology. At the group level, anatomical, chemical and functional differences have been reported, although these are often based on small samples. There are differences in the development and growth of certain brain areas, with stronger local and weaker global connections. Furthermore, the concentration of neurotransmitters such as GABA and serotonin is sometimes disbalanced in autism. Despite what was long thought, there are no clear differences in mirror neuronsystem activation during social tasks, but there are functional differences in other social brain areas, as well as in the cerebellum. Recently, the focus has been shifting to studying large-scale brain networks, a shift that generates new research lines and hypotheses, such as those related to the ‘predictive brain’. Research into autism and the brain is thus still strongly evolving.

Empathy Modulates the Activity of the Sensorimotor Mirror Neuron System during Pain Observation.

The aim of this study is to analyze the brain activity patterns during the observation of painful expressions and to establish the relationship between this activity and the scores obtained on the Interpersonal Reactivity Index (IRI). The study included twenty healthy, right-handed subjects (10 women). We conducted a task-based and resting-state functional magnetic resonance imaging (fMRI) study. The task involved observing pictures displaying painful expressions. We performed a region of interest (ROI) analysis focusing on the core regions of the sensorimotor mirror neuron system (MNS). Resting-state fMRI was utilized to assess the functional connectivity of the sensorimotor MNS regions with the rest of the cortex using a seed-to-voxel approach. Additionally, we conducted a regression analysis to examine the relationship between brain activity and scores from the IRI subtests. Observing painful expressions led to increased activity in specific regions of the frontal, temporal, and parietal lobes. The largest cluster of activation was observed in the left inferior parietal lobule (IPL). However, the ROI analysis did not reveal any significant activity in the remaining core regions of the sensorimotor MNS. The regression analysis demonstrated a positive correlation between brain activity during the observation of pain and the "empathic concern" subtest scores of the IRI in both the cingulate gyri and bilateral IPL. Finally, we identified a positive relationship between the "empathic concern" subtest of the IRI and the functional connectivity (FC) of bilateral IPLs with the bilateral prefrontal cortex and the right IFG. Observing expressions of pain triggers activation in the sensorimotor MNS, and this activation is influenced by the individual's level of empathy.

Effects of avatar shape and motion on mirror neuron system activity.

Humanness is an important characteristic for facilitating interpersonal communication, particularly through avatars in the metaverse. In this study, we explored the mirror neuron system (MNS) as a potential neural basis for perceiving humanness in avatars. Although previous research suggests that the MNS may be influenced by human-like shape and motion, the results have been inconsistent due to the diversity and complexity of the MNS investigation. Therefore, this study aims to investigate the effects of shape and motion humanness in avatars on MNS activity. Participants viewed videos of avatars with four different shapes (HumanShape, AngularShape, AbbreviatedShape, and ScatteredShape) and two types of motion (HumanMotion and LinearMotion), and their μ-wave attenuation in the electroencephalogram was evaluated. Results from a questionnaire indicated that HumanMotion was perceived as human-like, while AbbreviatedShape and ScatteredShape were seen as non-human-like. AngularShape's humanity was indefinite. The MNS was activated as expected for avatars with human-like shapes and/or motions. However, for non-human-like motions, there were differences in activity trends depending on the avatar shape. Specifically, avatars with HumanShape and ScatteredShape in LinearMotion activated the MNS, but the MNS was indifferent to AngularShape and AbbreviatedShape. These findings suggest that when avatars make non-human-like motions, the MNS is activated not only for human-like appearance but also for the scattered and exaggerated appearance of the human body in the avatar shape. These findings could enhance inter-avatar communication by considering brain activity.

Possible disrupted biological movement processing in Developmental Coordination Disorder

AimThere is emerging evidence that the Mirror Neuron System (MNS) might contribute to the motor learning difficulties characteristic of Developmental Coordination Disorder (DCD). This study aimed to identify whether MNS activity differed between children with and without DCD during action observation, action execution and during a non-action baseline. MethodsElectroencephalography (EEG) was used to measure mu rhythm (a proxy for MNS activation) in 8-12-year-old children either with (n = 20) or without (n = 19) a diagnosis of DCD. The mu rhythm was recorded at rest and during five experimental conditions: (1) observation of gross motor and (2) fine motor actions; (3) execution of gross motor and (4) fine motor actions; and (5) non-biological movement. To address whether potential co-occurring traits of other neurodevelopmental conditions were associated with differences in mu rhythm, parents reported their child's attention and social communication skills. Mixed and repeated measure ANOVAs were conducted to examine differences in mu desynchronization and mu power respectively. ResultsThe non-DCD group showed greater mu rhythm desynchronization than children with DCD (i.e., more MNS activity), with both groups demonstrating increasing desynchronization from observation of fine actions to execution of gross actions. However, we also found that the children with DCD had less mu power during the non-biological movement condition than the non-DCD children, although mu power did not differ between groups during the resting condition. Correlations between mu desynchronization and children's attention and motor skills showed that poorer attention and motor abilities were associated with reduced MNS activity. ConclusionCompared to children without DCD, the MNS in children with DCD did not distinguish between biological and non-biological movement. It is possible that the reduced specificity of the MNS in children with DCD is an underlying factor in the motor impairments observed in the disorder. The differential MNS activity could reflect broader atypical activity in perceptual networks that feed into the MNS in DCD.

Transdiagnostic investigation into the relationship between mirror neuron system activity, echo-phenomena, and theory of mind in major psychoses.

The association between social cognition and putative mirror neuron system (MNS)-activity in major psychoses might be contingent upon frontal dysregulation. We used a transdiagnostic ecological approach to enrich a specific behavioral phenotype (echophenomena or hyper-imitative states) across clinical diagnoses (mania and schizophrenia) to compare behavioral and physiological markers of social cognition and frontal disinhibition. We examined 114 participants with schizophrenia (N=53) and mania (N=61) for the presence and severity of echo-phenomena (echopraxia, incidental, and induced echolalia) using an ecological paradigm to simulate real-life social communication. Symptom severity, frontal release reflexes, and theory of mind performance were also assessed. In a proportion of these participants with (N=20) and without (N=20) echo-phenomena, we compared motor resonance (motor evoked potential facilitation during action observation compared to static image viewing) and cortical silent period (CSP) as putative markers of MNS-activity and frontal disinhibition, respectively, using Transcranial Magnetic Stimulation. While the prevalence of echo-phenomena was similar between mania and schizophrenia, incidental echolalia was more severe in mania. Participants with echo-phenomena (compared to those without) had significantly greater motor resonance with singlepulse (not with paired-pulse) stimuli, poorer theory of mind scores, higher frontal release reflexes but similar CSP, and greater symptom severity. None of these parameters significantly differed between participants with mania and schizophrenia. We observed relatively better phenotypic and neurophysiological characterization of major psychoses by categorizing participants based on the presence of echophenomena than clinical diagnoses. Higher putative MNS-activity was associated with poorer theory of mind in a hyper-imitative behavioral state.

Особенности реактивности μ-ритма ЭЭГ у детей с расстройствами аутистического спектра в ситуациях помогающего поведения

One of the subjects being discussed by the professional community currently is the role possibly played by the mirror neuron system (MNS) in the violation of social behavior of children with autism spectrum disorders (ASD). The MNS is known to shape the perception of emotions of others and understanding and imitation of their actions. Mu rhythm desynchronization in EEG is considered to be the indicator of the MNS activation. The purpose of this study was to identify the features of reactivity of the EEG mu rhythm within an individually determined frequency range in preschoolers with ASD in situations requiring instrumental, emotional and altruistic helping behavior (HB). The study involved children 4–7 years old with ASD (n = 26) and their normally developing peers without the condition (n = 37). Although in most cases, HB was more pronounced in the group of normally developing children, the differences between the groups are significant only for altruistic HP (p < 0.01), and for the situation requiring complex altruistic and emotional HP it approaches significance (p = 0.09). Evaluation of the mu rhythm reactivity indices showed that the tasks invoking complex altruistic and emotional HB bring this indicator down significantly in children with ASD compared to the group of normally developing participants, as shown by the central leads of the left and right hemispheres and the parietal lead of the right hemisphere (C3: p = 0.02 ; C4: p = 0.03; P4: p = 0.03). It is assumed that the detected features stem from the impaired functioning of the MNS and the downstream regulation to the MNS from prefrontal cortex and other areas of the neocortex. The data obtained can be used in development of EEG biofeedback training protocols for children with ASD.

ACTIVITY OF THE MIRROR NEURON SYSTEM IN PEOPLE WITH DEPRESSIVE SYMPTOMS

The global events of the last few years have led to the fact that more and more people are beginning to experience depressive symptoms. Developing depression significantly affects the emotional state of a person and his perception of the world around him. The purpose of this study was to analyze the reactions of mu- and alpha-rhythms reflecting the work of the mirror and visual systems of the brain, when perceiving and repeating emotionally colored social stimuli in people with different levels of depression. The study involved 32 healthy subjects who were divided into two groups – with high and low levels of depression on the Beck scale. A 32-channel EEG was recorded in two experimental blocks activating the emotional and motor components of the mirror neuron system (MNS): 1) when perceiving emotional faces expressing joy or grief; 2) when observing and repeating motor hand gestures. The desynchronization levels of the mu- and alpha-rhythm components in each of the tasks identified by the independent component method (ICA) were analyzed. It was found that the mu- desynchronization was significantly higher in people with depression when repeating motor hand movements, as well as when perceiving negative emotional facial expressions. Desynchronization of the alpha rhythm did not differ in the two groups of volunteers. Thus, the development of a depressive state increases MNS activation, and its sensitivity to negative emotional stimuli. This effect does not apply to the visual cortex and visual attention.

Motor Resonance During Action Observation and Its Relevance to Virtual Clinical Consultations: Observational Study Using Transcranial Magnetic Stimulation.

Virtual clinical interactions have increased tremendously since the onset of the COVID-19 pandemic. While they certainly have their advantages, there also exist potential limitations, for example, in establishing a therapeutic alliance, discussing complex clinical scenarios, etc. This may be due to possible disruptions in the accurate activation of the human mirror neuron system (MNS), a posited physiological template for effective social communication. This study aimed to compare motor resonance, a putative marker of MNS activity, estimated using transcranial magnetic stimulation (TMS) elicited while viewing virtual (video-based) and actual or real (enacted by a person) actions in healthy individuals. We hypothesized that motor resonance will be greater during real compared to virtual action observation. We compared motor resonance or motor-evoked potential (MEP) facilitation during the observation of virtual (presented via videos) and real (enacted in person) actions, relative to static image observation in healthy individuals using TMS. The MEP recordings were obtained by 2 single-pulse (neuronal membrane excitability-driven) TMS paradigms of different intensities and 2 paired-pulse (cortical gamma-aminobutyric acid-interneuron-driven) TMS paradigms. This study comprised 64 participants. Using the repeated measures ANOVA, we observed a significant time effect for MEP facilitation from static to virtual and real observation states when recorded using 3 of the 4 TMS paradigms. Post hoc pairwise comparisons with Benjamini-Hochberg false discovery rate correction revealed significant MEP facilitation in both virtual and real observation states relative to static image observation; however, we also observed a significant time effect between the 2 action observation states (real > virtual) with 2 of the 4 TMS paradigms. Our results indicate that visual cues expressed via both virtual (video) or real (in person) modes elicit physiological responses within the putative MNS, but this effect is more pronounced for actions presented in person. This has relevance to the appropriate implementation of digital health solutions, especially those pertaining to mental health.

Enhanced mirror neuron network activity and effective connectivity during live interaction among female subjects

Facial expressions are indispensable in daily human communication. Previous neuroimaging studies investigating facial expression processing have presented pre-recorded stimuli and lacked live face-to-face interaction. Our paradigm alternated between presentations of real-time model performance and pre-recorded videos of dynamic facial expressions to participants. Simultaneous functional magnetic resonance imaging (fMRI) and facial electromyography activity recordings, as well as post-scan valence and arousal ratings were acquired from 44 female participants. Live facial expressions enhanced the subjective valence and arousal ratings as well as facial muscular responses. Live performances showed greater engagement of the right posterior superior temporal sulcus (pSTS), right inferior frontal gyrus (IFG), right amygdala and right fusiform gyrus, and modulated the effective connectivity within the right mirror neuron system (IFG, pSTS, and right inferior parietal lobule). A support vector machine algorithm could classify multivoxel activation patterns in brain regions involved in dynamic facial expression processing in the mentalizing networks (anterior and posterior cingulate cortex). These results indicate that live social interaction modulates the activity and connectivity of the right mirror neuron system and enhances spontaneous mimicry, further facilitating emotional contagion.

The Reaching Phase of Feeding and Self-Care Actions Optimizes Action Observation Effects in Chronic Stroke Subjects

Background The Action Observation Therapy (AOT) is a well-established post-stroke rehabilitation treatment based on the theoretical framework of the Mirror Neuron System (MNS) activation. However, AOT protocols are still heterogeneous in terms of video contents of observed actions. Objective The aim of this study was to analyze electroencephalographic (EEG) recordings in stroke patients during the observation of different videos of task-specific upper limb movements, and to define which category of actions can elicit a stronger cortical activation in the observer’s brain. Methods Signals were analyzed from 19 chronic stroke subjects observing customized videos that represented 3 different categories of upper limb actions: Finalized Actions, Non-Finalized Actions, and Control Videos. The Event-Related Desynchronization in the µ and β bands was chosen to identify the involvement of the cerebral cortex: the area of the normalized power spectral density was calculated for each category and, deepening, for the reaching and completion sub-phases of Finalized Actions. For descriptive purposes, the time course of averaged signal power was described. The Kruskal–Wallis test (P < .05) was applied. Results The analysis showed a greater desynchronization when subjects observed Finalized Actions with respect to Non-Finalized in all recorded areas; Control videos provoked a synchronization in the same areas and frequency bands. The reaching phase of feeding and self-care actions evoked a greater suppression both in µ and β bands. Conclusions The observation of finalized arm movements seems to elicit the strongest activation of the MNS in chronic stroke patients. This finding may help the clinicians to design future AOT-based stroke rehabilitation protocols. Clinical Trial Registration: Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: NCT04047134.

The degree of mu rhythm suppression in women is associated with presence of children as well as empathy and anxiety level

ABSTRACT In experiments on observing and performing social gestures, the level of mu rhythm suppression is associated with the activity of the mirror neuron system (MNS), which is responsible for the perception and understanding of nonverbal signals in social communication. In turn, while MNS activity may be associated primarily with empathy, it is also associated with other psychological and demographic factors affecting the effectiveness of cortical neural networks. In this study, we verified the influence of empathy, state and trait anxiety levels, presence and number of children, and age on the mu-suppression level in 40 women. We used 32-channel EEG recorded during observation, and synchronous execution of various hand movements. The ICA infomax method was used for decomposing and selecting the left hemisphere component of the mu-rhythm. Mu-suppression was higher in women with one child, with higher levels of empathy, and with lower anxiety levels. It is possible that MNS activity is stronger in women during parental care.

Differential beta desynchronisation responses to dynamic emotional facial expressions are attenuated in higher trait anxiety and autism

Daily life demands that we differentiate between a multitude of emotional facial expressions (EFEs). The mirror neuron system (MNS) is becoming increasingly implicated as a neural network involved with understanding emotional body expressions. However, the specificity of the MNS’s involvement in emotion recognition has remained largely unexplored. This study investigated whether six basic dynamic EFEs (anger, disgust, fear, happiness, sadness, and surprise) would be differentiated through event-related desynchronisation (ERD) of sensorimotor alpha and beta oscillatory activity, which indexes sensorimotor MNS activity. We found that beta ERD differentiated happy, fearful, and sad dynamic EFEs at the central region of interest, but not at occipital regions. Happy EFEs elicited significantly greater central beta ERD relative to fearful and sad EFEs within 800 - 2,000 ms after EFE onset. These differences were source-localised to the primary somatosensory cortex, which suggests they are likely to reflect differential sensorimotor simulation rather than differential attentional engagement. Furthermore, individuals with higher trait anxiety showed less beta ERD differentiation between happy and sad faces. Similarly, individuals with higher trait autism showed less beta ERD differentiation between happy and fearful faces. These findings suggest that the differential simulation of specific affective states is attenuated in individuals with higher trait anxiety and autism. In summary, the MNS appears to support the skills needed for emotion processing in daily life, which may be influenced by certain individual differences. This provides novel evidence for the notion that simulation-based emotional skills may underlie the emotional difficulties that accompany affective disorders, such as anxiety.

Feasibility of fNIRS in Children with Developmental Coordination Disorder

IntroductionBalance deficits are heterogeneous among children with Developmental Coordination Disorder (DCD). Balance performance depends on different balance domains, each associated with specific underlying neurological systems. In DCD, any of these domains can be affected, but the control mechanisms are poorly understood. The mirror neuron system (MNS) seems to play a key-role in DCD-related deficits. To understand the role of MNS as a control mechanism underlying the balance deficits, simultaneous registration of cortical MNS activity while performing balance tasks is imperative. Therefore, a protocol for combining real-time registration of cortical MNS activity during functional balance tasks in children with DCD, CP and TD is introduced. Methods: Children with DCD, CP and TD (n=108) aged 5-10yr perform preselected tasks of the Kids-BESTest, representing specific balance domains (mixed design): leaning with eyes closed (stability limits/verticality), single-leg-stance, alternate stair touching (anticipatory balance), in-place response, compensatory stepping backward (reactive balance) and walking over obstacles (gait stability). Simultaneously, functional Near-Infrared Spectroscopy (fNIRS) monitors cortical activity involving the MNS: premotor, inferior and superior parietal cortex and supplementary motor area. An 8-8-optode bundle, making 22 channels, targets this region of interest. Outcome measures are: (de)oxygenated hemoglobin concentration changes per task per channel. Results: In this ongoing research, the protocol was already feasible in 19 children (7.52±1.19). Conclusion: Simultaneous registration of cortical MNS activity (fNIRS) and Kids-BESTest scores will help increase the understanding of the control mechanisms underlying the heterogeneous balance problems in DCD. Consequently, first steps are made to confirm whether DCD shows deviant or delayed development.DisclosureNo significant relationships.

Is there a relationship between EEG and sTMS neurophysiological markers of the putative human mirror neuron system?

The mirror neuron system (MNS) has been theorized to play a neurobiological role in a number of social cognitive abilities and is commonly indexed putatively in humans via interpersonal motor resonance (IMR) and mu suppression. Although both indices are thought to measure similar neuronal populations (i.e., "mirror neurons"), it has been suggested that these methods are unrelated, and therefore, incompatible. However, prior studies reporting no relationships were typically conducted in small and underpowered samples. Thus, we aimed to investigate this potential association in a large sample of neurotypical adults (N=116; 72 females). Participants underwent transcranial magnetic stimulation (TMS), electromyography (EMG), and electroencephalography (EEG) during the observation of videos of actors performing grasping actions in order to index IMR and mu suppression (in beta, lower alpha, and upper alpha bandwidths). A series of linear regressions revealed no associations between IMR and each of the mu suppression bandwidths. Supplementary Bayesian analyses provided further evidence in favor of the null (B01 =8.85-8.93), providing further support for no association between the two indices of MNS activity. Our findings suggest that these two measures may indeed be unrelated indices that perhaps assess different neurophysiological aspects of the MNS. These results have important implications for future studies examining the MNS.

Altering Facial Movements Abolishes Neural Mirroring of Facial Expressions

People tend to automatically imitate others’ facial expressions of emotion. That reaction, termed “facial mimicry” has been linked to sensorimotor simulation—a process in which the observer’s brain recreates and mirrors the emotional experience of the other person, potentially enabling empathy and deep, motivated processing of social signals. However, the neural mechanisms that underlie sensorimotor simulation remain unclear. This study tests how interfering with facial mimicry by asking participants to hold a pen in their mouth influences the activity of the human mirror neuron system, indexed by the desynchronization of the EEG mu rhythm. This response arises from sensorimotor brain areas during observed and executed movements and has been linked with empathy. We recorded EEG during passive viewing of dynamic facial expressions of anger, fear, and happiness, as well as nonbiological moving objects. We examine mu desynchronization under conditions of free versus altered facial mimicry and show that desynchronization is present when adult participants can freely move but not when their facial movements are inhibited. Our findings highlight the importance of motor activity and facial expression in emotion communication. They also have important implications for behaviors that involve occupying or hiding the lower part of the face.

Observation, imaginary performance and actual performance of motor tasks in patients with temporal lobe epilepsy: An EEG study

Numerous studies indicate that during the observation and imaginary performance of movements, a decrease in the sensorimotor mu-rhythm in the central regions of the scalp reflects the degree of the mirror neuron system (MNS) activity, which ensures the perception of non-verbal signals during social interactions. Proof of the existence of the MNS in humans and subsequent invasive studies of its properties were carried out with the participation of patients with epilepsy, while the possible disruptions of the MNS in these patients were not taken into account. In this work, we analyzed the responses of the sensorimotor rhythm to the observation, imaginary performance and actual performance of various movements in patients with temporal lobe epilepsy and control group participants. It was found that mu-desynchronization is more pronounced in patients with epilepsy than in control group participants in the upper frequency (10.5 – 13 Hz) sub-band. Characteristic differences between the groups also emerged during tasks associated with movements that require two hands