Effects of observing own/others hand movement in different perspectives on mu rhythm suppression: an EEG study.

BACKGROUND: Previous studies have reported that the sense of "self" is associated with specific brain regions and neural network activities. In addition, the mirror system, which functions when executing or observing an action, might contribute to differentiating the self from others and form the basis of the sense of self as a fundamental physical representation. This study investigated whether differences in mu suppression, an indicator of mirror system activity, reflect cognitions related to self-other discrimination. METHODS: The participants were 30 of healthy college students. The participants observed short video clips of hand movements performed by themselves or actors from two perspectives (i.e., first-person and third-person). The electroencephalogram (EEG) mu rhythm (8-13 Hz) was measured during video observation as an index of mirror neuron system activity. EEG activity related to self-detection was analyzed using participants' hand movements as self-relevant stimuli. RESULTS: The results showed that mu suppression in the 8-13-Hz range exhibited perspective-dependent responses to self/other stimuli. There was a significant self-oriented mu suppression response in the first-person perspective. However, the study found no significant response orientation in the third-person perspective. The results suggest that mirror system activity may involve self-other discrimination differently depending on the perspective. CONCLUSIONS: In summary, this study examined the mirror system's activity for self and others using the EEG's mu suppression. As a result, it was suggested that differences in self and others or perspectives may influence mu suppression.

Synergy of the mirror neuron system and the mentalizing system in a single brain and between brains during joint actions.

Cooperative action involves the simulation of actions and their co-representation by two or more people. This requires the involvement of two complex brain systems: the mirror neuron system (MNS) and the mentalizing system (MENT), both of critical importance for successful social interaction. However, their internal organization and the potential synergy of both systems during joint actions (JA) are yet to be determined. The aim of this study was to examine the role and interaction of these two fundamental systems-MENT and MNS-during continuous interaction. To this hand, we conducted a multiple-brain connectivity analysis in the source domain during a motor cooperation task using high-density EEG dual-recordings providing relevant insights into the roles of MNS and MENT at the intra- and interbrain levels. In particular, the intra-brain analysis demonstrated the essential function of both systems during JA, as well as the crucial role played by single brain regions of both neural mechanisms during cooperative activities. Specifically, our intra-brain analysis revealed that both neural mechanisms are essential during Joint Action (JA), showing a solid connection between MNS and MENT and a central role of the single brain regions of both mechanisms during cooperative actions. Additionally, our inter-brain study revealed increased inter-subject connections involving the motor system, MENT and MNS. Thus, our findings show a mutual influence between two interacting agents, based on synchronization of MNS and MENT systems. Our results actually encourage more research into the still-largely unknown realm of inter-brain dynamics and contribute to expand the body of knowledge in social neuroscience.

[Possibilities of mirror therapy in cognitive rehabilitation after stroke]. / Vozmozhnosti zerkal'noi terapii v kognitivnoi reabilitatsii posle insul'ta.

The review provides a brief overview of the history of the development of mirror therapy. Current data on the putative mechanisms of mirror therapy as well as the theory of mirror neurons are presented. The authors describe the implementation of the effects of mirror therapy in motor rehabilitation after stroke, including motor imagination or mental simulation of actions, strengthening of spatial attention and self-perception, activation of the ipsilateral corticospinal tract, reorganization of neuronal networks that influence the state of structurally intact but functionally inactive neurons. The authors reflected the prerequisites for the use of mirror therapy in the rehabilitation of cognitive impairment in poststroke patients. The results of current clinical studies and case reports of the use of mirror therapy for the rehabilitation of speech and non-speech cognitive disorders, and neglect syndrome after stroke are presented.

The cerebellum and the Mirror Neuron System: A matter of inhibition? From neurophysiological evidence to neuromodulatory implications. A narrative review.

Mirror neurons show activity during both the execution (AE) and observation of actions (AO). The Mirror Neuron System (MNS) could be involved during motor imagery (MI) as well. Extensive research suggests that the cerebellum is interconnected with the MNS and may be critically involved in its activities. We gathered evidence on the cerebellum's role in MNS functions, both theoretically and experimentally. Evidence shows that the cerebellum plays a major role during AO and MI and that its lesions impair MNS functions likely because, by modulating the activity of cortical inhibitory interneurons with mirror properties, the cerebellum may contribute to visuomotor matching, which is fundamental for shaping mirror properties. Indeed, the cerebellum may strengthen sensory-motor patterns that minimise the discrepancy between predicted and actual outcome, both during AE and AO. Furthermore, through its connections with the hippocampus, the cerebellum might be involved in internal simulations of motor programs during MI. Finally, as cerebellar neuromodulation might improve its impact on MNS activity, we explored its potential neurophysiological and neurorehabilitation implications.

Brain activations during execution and observation of visually guided sequential manual movements in autism and in typical development: A study protocol.

Motor issues are frequently observed accompanying core deficits in autism spectrum disorder (ASD). Impaired motor behavior has also been linked to cognitive and social abnormalities, and problems with predictive ability have been suggested to play an important, possibly shared, part across all these domains. Brain imaging of sensory-motor behavior is a promising method for characterizing the neurobiological foundation for this proposed key trait. The present functional magnetic resonance imaging (fMRI) developmental study, involving children/youth with ASD, typically developing (TD) children/youth, and neurotypical adults, will investigate brain activations during execution and observation of a visually guided, goal-directed sequential (two-step) manual task. Neural processing related to both execution and observation of the task, as well as activation patterns during the preparation stage before execution/observation will be investigated. Main regions of interest include frontoparietal and occipitotemporal cortical areas, the human mirror neuron system (MNS), and the cerebellum.

Online chasing action recruits both mirror neuron and mentalizing systems: A pilot fNIRS study.

Engaging in chasing, where an actor actively pursues a target, is considered a crucial activity for the development of social skills. Previous studies have focused predominantly on understanding the neural correlates of chasing from an observer's perspective, but the neural mechanisms underlying the real-time implementation of chasing action remain poorly understood. To gain deeper insights into this phenomenon, the current study employed functional near-infrared spectroscopy (fNIRS) techniques and a novel interactive game. In this interactive game, participants (N = 29) were tasked to engage in chasing behavior by controlling an on-screen character using a gamepad, with the goal of catching a virtual partner. To specifically examine the brain activations associated with the interactive nature of chasing, we included two additional interactive actions: following action of following the path of a virtual partner and free action of moving without a specific pursuit goal. The results revealed that chasing and following actions elicited activation in a broad and overlapping network of brain regions, including the temporoparietal junction (TPJ), medial prefrontal cortex (mPFC), premotor cortex (PMC), primary somatosensory cortex (SI), and primary motor cortex (M1). Crucially, these regions were found to be modulated by the type of interaction, with greater activation and functional connectivity during the chasing interaction than during the following and free interactions. These findings suggested that both the MNS, encompassing regions such as the PMC, M1 and SI, and the mentalizing system (MS), involving the TPJ and mPFC, contribute to the execution of online chasing actions. Thus, the present study represents an initial step toward future investigations into the roles of MNS and MS in real-time chasing interactions.

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.

Upper Limb Electromyographic Responses to Motor Imagery and Action Observation in Acquired Brain Injury.

Acquired Brain Injuries are one of the leading causes of mortality and disability worldwide. One of the most frequent sequelae is motor impairment of the upper limbs, which affects people's functionality and quality of life. Following the discovery of mirror neurons, new techniques were developed based on the mechanisms of neuronal plasticity, such as motor imagery (MI) and action observation (AO). We propose a protocol using electromyographic recordings of forearm muscles in people who have suffered a stroke during an MI task and an AO task. Three different experimental conditions will be studied during the electromyographic recordings: control recording, recording during MI, and recording during AO. Understanding the muscle activation in each technique will allow us to develop future protocols and intervention plans, improving the quality of care for people who have suffered a stroke.

Effects of mirror neuron activation therapies on functionality in older adults: Systematic review and meta-analysis.

PURPOSE: To identify the effects of mirror neuron activation (MNAT) combined or not with physical exercise (PE) in healthy older adults, on functionality, balance, gait velocity and risk of falls. METHODS: A systematic electronic search was performed in PubMed/MEDLINE, Cochrane, and Embase databases. RESULTS: Thirteen randomized controlled trials were included in the qualitative analysis, and eleven in the quantitative analysis. All studies showed fair to high quality and the most frequent high-risk bias was "Blinding of participants and personnel". Compared to the control condition, higher improvement was shown in older people who received MNAT, on functionality (1.57 [0.57, 2.62], balance (1.95 [1.32, 2.572]), and gait velocity (1.20 [0.30, 2.11]). Compared to PE, MNAT combined with PE does not improve functionality. More studies are needed to assess MNAT effectiveness in the rest of the outcomes. CONCLUSIONS: Neuron system activation through MNAT improves relevant abilities in older adults, with better results when including functional activities. However, the beneficial effects on these variables of adding MNAT to a PE program are controversial.

Comparison of Spectral Analysis of Gamma Band Activity During Actual and Imagined Movements as a Cognitive Tool.

Background. Imagined motor movement is a cognitive process in which a subject imagines a movement without doing it, which activates similar brain regions as during actual motor movement. Brain gamma band activity (GBA) is linked to cognitive functions such as perception, attention, memory, awareness, synaptic plasticity, motor control, and Imagination. Motor imagery can be used in sports to improve performance, raising the possibility of using it as a rehabilitation method through brain plasticity through mirror neurons. Method. A comparative observational study was conducted on 56 healthy male subjects after obtaining clearance from the Ethics Committee. EEG recordings for GBA were taken for resting, real, and imaginary motor movements and compared. The power spectrum of gamma waves was analyzed using the Kruskal-Wallis test; a p-value <.05 was considered significant. Results. The brain gamma rhythm amplitude was statistically increased during both actual and imaginary motor movement compared to baseline (resting stage) in most of the regions of the brain except the occipital region. There was no significant difference in GBA between real and imaginary movements. Conclusions. Increased gamma rhythm amplitude during both actual and imaginary motor movement than baseline (resting stage) indicating raised brain cognitive activity during both types of movements. There was no potential difference between real and imaginary movements suggesting that the real movement can be replaced by the imaginary movement to enhance work performance through mirror therapy.

Effects of a single session action observation training on hand function in healthy young adults: a randomised controlled assessor and participants-blinded trial.

PURPOSE: The aim was to investigate the effects of a single session action observation training (AOT) on hand function and evaluate whether observing self-actions would be more effective than observing someone else. MATERIALS AND METHODS: A total of 60 right-handed healthy young adults, (32 female, 28 males and the mean age was 21.32 ± 1.07 years) were included in the study. The participants were randomly divided into five groups, self-action observation (sAO), observation of a third person (AO), action practice (AP), non-action observation (nAO), and control. A single session was performed for all participants. The primary outcome was the Jebsen Taylor Hand Function Test (JTHFT) assessed by a masked assessor. RESULTS: Significant differences were observed between the sAO and control group in total left side JTHFT performance (p < 0.001). Additionally, there were significant differences between the AO and control group (p < 0.001), and AP and nAO group (p = 0.003) and AP and control group (p < 0.001) in total JTHFT performance change of the left side. Significant differences were found between the sAO and nAO (p = 0.001) and control groups (p < 0.001) in dominant side total JTHFT performance change. No difference between sAO and AP groups were observed (p > 0.05). CONCLUSION: It was observed that a single session of action observation training improved hand function in healthy adults. The better performance achieved in the group watching the self-video may suggest that watching the self-image activates more mirror neurons.

Facial emotional congruence in healthy adults and patients suffering from a psychiatric or neurological disorder.

The production of facial emotions is an important conveyor of social communication. The present review of the literature concerns the congruence of facial emotions, that is the facial muscular activation that takes place in response to the emotional facial expression perceived in others. Although scientific interest in facial emotions has increased exponentially in the last few years, the production of facial emotions is still underexplored as compared to emotional perception. Several studies, mainly conducted with electromyography, have shown that facial emotional congruence exists in a robust way, largely for anger and happiness. While facial emotional congruence was long considered as innate and automatic, recent work has demonstrated that several sociocultural factors may influence or reduce this ability, challenging its automaticity. From a neuroanatomical point of view, studies have clearly highlighted the implication of mirror neurons but our knowledge is still limited because of the few methodologies assessing this system and the lack of homogeneity between the protocols used. Many explanatory, and probably not mutually exclusive, theories of emotional facial congruence have been put forward. In experimental neuropsychology, emotional facial congruence has seldom been investigated but the few available results suggest an impairment in psychiatric and neurological patients. In view of the important role of emotional facial productions in human relations and social interactions, new methods for easy clinical assessment need to be designed for the diagnosis and the cognitive care of these abilities. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Are there dedicated neural mechanisms for imitation? A study of grist and mills.

Are there brain regions that are specialized for the execution of imitative actions? We compared two hypotheses of imitation: the mirror neuron system (MNS) hypothesis predicts frontal and parietal engagement which is specific to imitation, while the Grist-Mills hypothesis predicts no difference in brain activation between imitative and matched non-imitative actions. Our delayed imitation fMRI paradigm included two tasks, one where correct performance was defined by a spatial rule and another where it was defined by an item-based rule. For each task, participants could learn a sequence from a video of a human hand performing the task, from a matched "Ghost" condition, or from text instructions. When participants executed actions after seeing the Hand demonstration (compared to Ghost and Text demonstrations), no activation differences occurred in frontal or parietal regions; rather, activation was localized primarily to occipital cortex. This adds to a growing body of evidence which indicates that imitation-specific responses during action execution do not occur in canonical mirror regions, contradicting the mirror neuron system hypothesis. However, activation differences did occur between action execution in the Hand and Ghost conditions outside MNS regions, which runs counter to the Grist-Mills hypothesis. We conclude that researchers should look beyond these hypotheses as well as classical MNS regions to describe the ways in which imitative actions are implemented by the brain.

Non-shared coding of observed and executed actions prevails in macaque ventral premotor mirror neurons.

According to the mirror mechanism the discharge of F5 mirror neurons of a monkey observing another individual performing an action is a motor representation of the observed action that may serve to understand or learn from the action. This hypothesis, if strictly interpreted, requires mirror neurons to exhibit an action tuning that is shared between action observation and execution. Due to insufficient data it remains contentious if this requirement is met. To fill in the gaps, we conducted an experiment in which identical objects had to be manipulated in three different ways in order to serve distinct action goals. Using three methods, including cross-task classification, we found that at most time points F5 mirror neurons did not encode observed actions with the same code underlying action execution. However, in about 20% of neurons there were time periods with a shared code. These time periods formed a distinct cluster and cannot be considered a product of chance. Population classification yielded non-shared coding for observed actions in the whole population, which was at times optimal and consistently better than shared coding in differentially selected subpopulations. These results support the hypothesis of a representation of observed actions based on a strictly defined mirror mechanism only for small subsets of neurons and only under the assumption of time-resolved readout. Considering alternative concepts and recent findings, we propose that during observation mirror neurons represent the process of a goal pursuit from the observer's viewpoint. Whether the observer's goal pursuit, in which the other's action goal becomes the observer's action goal, or the other's goal pursuit is represented remains to be clarified. In any case, it may allow the observer to use expectations associated with a goal pursuit to directly intervene in or learn from another's action.

Reflexive structure of the conscious subject and the origin of language codes.

The code paradigm in biological and social sciences arises to Aristotle. For conscious activity, Aristotle introduced the notion of reflexive self-awareness in sense perception. This reflexive process generates the codes that signify sensual perceptive events and constrain human behavior. Coding systems grow via the generation of hypertextual statements reflecting new meanings in the process defined by Marcello Barbieri as a codepoiesis. It results in the establishment of higher-level codes (metacodes) forming the semiotic screen that has a nature of the set of perceived objects internalized by the conscious subject in encoding the symbolic actions. The characteristic feature of the semiotic screen consists in its property of being shared between the communicating agents. A sufficient complexity of nervous system, through the appearance of mirror neurons that are fired both when a subject executes certain action and when he observes another subject performing a similar action, represents a prerequisite for the emergence of reflexive codes in evolution. The codes appearing as a result of reflexive awareness and establishing different sociotypes, span from the symbolic systems of art and music through the common language to the formal language of logic and mathematics. Social dynamics is based on the implementation of reflexive coding activity and results in the growth and decay of social systems and civilizations.

Differential responses in the mirror neuron system during imitation of individual emotional facial expressions and association with autistic traits.

The mirror neuron system (MNS), including the inferior frontal gyrus (IFG), inferior parietal lobule (IPL) and superior temporal sulcus (STS) plays an important role in action representation and imitation and may be dysfunctional in autism spectrum disorder (ASD). However, it's not clear how these three regions respond and interact during the imitation of different basic facial expressions and whether the pattern of responses is influenced by autistic traits. Thus, we conducted a natural facial expression (happiness, angry, sadness and fear) imitation task in 100 healthy male subjects where expression intensity was measured using facial emotion recognition software (FaceReader) and MNS responses were recorded using functional near-infrared spectroscopy (fNIRS). Autistic traits were measured using the Autism Spectrum Quotient questionnaire. Results showed that imitation of happy expressions produced the highest expression intensity but a small deactivation in MNS responses, suggesting a lower processing requirement compared to other expressions. A cosine similarity analysis indicated a distinct pattern of MNS responses during imitation of each facial expression with functional intra-hemispheric connectivity between the left IPL and left STS being significantly higher during happy compared to other expressions, while inter-hemispheric connectivity between the left and right IPL differed between imitation of fearful and sad expressions. Furthermore, functional connectivity changes during imitation of each different expression could reliably predict autistic trait scores. Overall, the results provide evidence for distinct patterns of functional connectivity changes between MNS regions during imitation of different emotions which are also associated with autistic traits.

Motor resonance to non-visible postural adaptation: A novel aspect of the mirror mechanism.

The activation of the Mirror Neuron System (MNS) has been described to reflect visible movements, but not postural, non-visible, adaptations that accompany the observed movements. Since any motor act is the result of a well-tailored dialogue between these two components, we decided to investigate whether a motor resonance to nonvisible postural adaptations could be detected. Possible changes in soleus corticospinal excitability were investigated by eliciting the H-reflex during the observation of three videos, corresponding to three distinct experimental conditions: 'Chest pass', 'Standing' and 'Sitting', and comparing its size with that measured during observation of a control videoclip (a landscape). In the observed experimental conditions, the Soleus muscle has different postural roles: a dynamic role in postural adaptations during the Chest pass; a static role while Standing still; no role while Sitting. The H-reflex amplitude was significantly enhanced in the 'Chest pass' condition compared to the 'Sitting' and 'Standing' conditions. No significant difference was found between 'Sitting' and 'Standing' conditions. The increased corticospinal excitability of the Soleus during the 'Chest pass' condition suggests that the mirror mechanisms produce a resonance to postural components of an observed action, although they may not be visible. This observation highlights the fact that mirror mechanisms echo non intentional movements as well and points to a novel possible role of mirror neurons in motor recovery.

Aggression: The dark side of mirror neurons sheds light on their functions.

Mirror neurons have been found mainly in neocortical structures of primates and rodents; however, their functions are still debated. A new study has discovered mirror neurons for aggressive behaviors in the ventromedial hypothalamus of mice, an evolutionarily ancient structure, highlighting a new function key for survival.

Effects of integrated action and sensory observation therapy based on mirror neuron and embodied cognition theory on upper limb sensorimotor function in chronic stroke: a study protocol for a randomised controlled trial.

INTRODUCTION: This study protocol aims to explore the effectiveness and neural mechanism of the integration of action observation therapy (AOT) and sensory observation therapy (SOT) for post-stroke patients on upper limb sensorimotor function. METHODS AND ANALYSIS: This is a single-centre, single-blind, randomised controlled trial. A total of 69 patients with upper extremity hemiparesis after stroke will be recruited and randomly divided into an AOT group, a combined action observation and somatosensory stimulation therapy (AOT+SST) group, and a combined AOT and SOT (AOT+SOT) group in a 1:1:1 ratio. Each group will receive 30 min of daily treatment, five times weekly for 4 weeks. The primary clinical outcome will be the Fugl-Meyer Assessment for Upper Extremity. Secondary clinical outcomes will include the Box and Blocks Test, modified Barthel Index and sensory assessment. All clinical assessments and resting-state functional MRI and diffusion tensor imaging data will be obtained at pre-intervention (T1), post-intervention (T2) and 8 weeks of follow-up (T3). ETHICS AND DISSEMINATION: The trial was approved by the Ethics Committee of Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Chinese Traditional Medicine (Grant No. 2020-178). The results will be submitted to a peer-review journal or at a conference. TRIAL REGISTRATION NUMBER: ChiCTR2000040568.

To see is to experience: Aggression neurons light up when witnessing a fight.

Fighting is an intense experience not only for the executors but also for the observers. In the current issue of Cell, Yang et al. identified hypothalamic aggression mirror neurons, activated during both physical fighting and witnessing a fight, possibly representing a neural mechanism for understanding social experiences in other minds.