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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. [ABSTRACT FROM AUTHOR]

Background: Video-feedback observational therapy (VOT) is an intensive rehabilitation technique based on movement repetition and visualization that has shown benefits for motor rehabilitation of the upper and lower limbs. Despite an increase in recent literature on the neurophysiological effects of VOT in the upper limb, there is little knowledge about the cortical effects of visual feedback therapies when applied to the lower limbs. The aim of our study was to better understand the neurophysiological effects of VOT. Thus, we identified and compared the EEG biomarkers of healthy subjects undergoing lower limb VOT during three tasks: passive observation, observation and motor imagery, observation and motor execution. Methods: We recruited 38 healthy volunteers and monitored their EEG activity while they performed a right ankle dorsiflexion task in the VOT. Three graded motor tasks associated with action observation were tested: action observation alone (O), motor imagery with action observation (OI), and motor execution synchronized with action observation (OM). The alpha and beta event-related desynchronization (ERD) and event-related synchronization (or beta rebound, ERS) rhythms were used as biomarkers of cortical activation and compared between conditions with a permutation test. Changes in connectivity during the task were computed with phase locking value (PLV). Results: During the task, in the alpha band, the ERD was comparable between O and OI activities across the precentral, central and parietal electrodes. OM involved the same regions but had greater ERD over the central electrodes. In the beta band, there was a gradation of ERD intensity in O, OI and OM over central electrodes. After the task, the ERS changes were weak during the O task but were strong during the OI and OM (Cz) tasks, with no differences between OI and OM. Conclusion: Alpha band ERD results demonstrated the recruitment of mirror neurons during lower limb VOT due to visual feedback. Beta band ERD reflects strong recruitment of the sensorimotor cortex evoked by motor imagery and action execution. These results also emphasize the need for an active motor task, either motor imagery or motor execution task during VOT, to elicit a post-task ERS, which is absent during passive observation. Trial Registration NCT05743647 [ABSTRACT FROM AUTHOR]

Action observation (AO) and motor imagery (MI) has emerged as promising tool for physiotherapy intervention in Parkinson's disease (PD). This narrative review summarizes why, how, and when applying AO and MI training in individual with PD. We report the neural underpinning of AO and MI and their effects on motor learning. We examine the characteristics and the current evidence regarding the effectiveness of physiotherapy interventions and we provide suggestions about their implementation with technologies. Neurophysiological data suggest a substantial correct activation of brain networks underlying AO and MI in people with PD, although the occurrence of compensatory mechanisms has been documented. Regarding the efficacy of training, in general evidence indicates that both these techniques improve mobility and functional activities in PD. However, these findings should be interpreted with caution due to variety of the study designs, training characteristics, and the modalities in which AO and MI were applied. Finally, results on long-term effects are still uncertain. Several elements should be considered to optimize the use of AO and MI in clinical setting, such as the selection of the task, the imagery or the video perspectives, the modalities of training. However, a comprehensive individual assessment, including motor and cognitive abilities, is essential to select which between AO and MI suite the best to each PD patients. Much unrealized potential exists for the use AO and MI training to provide personalized intervention aimed at fostering motor learning in both the clinic and home setting. [ABSTRACT FROM AUTHOR]

The aim of the study is to understand how Mirror Neuron System (MNS) and Mentalizing Network (MZN) interact with each other. EEG data was collected during a photo judgment task with pictures of actions or facial expressions. Participants (N = 30, 63% women) were asked to either identify how the shown action/expression was being performed (MNS) or what the goal or intention behind the action was (MZN). Data were analyzed using microstate analysis, source localization and Event-Related Potentials. When comparing the action types, we found early divergence between the brain states of MNS and MZN when comparing the same action type. There was temporal alignment between the start and end time of the induced microstates, among the same action type. Between different action types, the timing was slightly shifted. Temporally, there was a greater overlap between the timing of the states between networks within the same action type as compared to within networks across action types. The MNS and MZN are acting in parallel rather then subsequently and possibly feed into each other. Furthermore, the MNS and MZN do not specifically react to one action type over the other, but their activity is influenced by the action type. [ABSTRACT FROM AUTHOR]

Aim: 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). Methods: 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. Results: 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. Conclusion: Observing expressions of pain triggers activation in the sensorimotor MNS, and this activation is influenced by the individual's level of empathy. [ABSTRACT FROM AUTHOR]

Background/aim: The firing rate of the mirror neuron system in monkeys decreases systematically with more repetitions. The aim of this study is to investigate whether the activity of the mirror neuron system varies based on the observed movement and the contents of the action, as well as whether there is inhibition in the mirror neuron system when humans observe repeated actions. If inhibition is present, the second question of the study is whether it is related to the organization of the observed action. Materials and methods: Fourteen healthy volunteers participated in the study. Transcranial magnetic stimulation was applied to the left primary motor cortex and motor evoked potentials (MEPs) were recorded from the right first dorsal interosseous and abductor pollicis brevis muscles while the participants were watching videos specially prepared for the study. Results: There were no significant changes in MEP amplitudes compared to baseline MEPs while observing aimless action. However, while participants watched the repeated action video, the mean MEP amplitude increased at the beginning of the movement, but neither facilitation nor inhibition was detected when the participants watched the phase of grasping the object of the action compared to the baseline MEP amplitude. On the other hand, while participants were watching different activities, an increased MEP amplitude was observed at the beginning of the movement and in the grasping of the object of the action. Additionally, there was no significant reduction in MEP amplitude during any movement stages while observing the repeated action video. Conclusion: The findings of this study suggest that the activation of the mirror neuron system in humans depends on the content and stages of the observed movement. Additionally, there was no inhibition or systematic reduction in MEP amplitudes while watching a repeated action. [ABSTRACT FROM AUTHOR]

Studying mu-rhythm in developmental disorders is crucial for identifying the origin of motor and social malfunctioning. However, the commonly used mu-rhythm experimental protocol, that requires following instructions, is challenging for children with motor and cognitive deficits. Here we present an inclusive experimental procedure that contains passive hand movement, closed and open eyes and hand movement observation and examine properties of EEG mu-rhythm obtained in this paradigm in 51 typically developing children and adults aged from 4 to 31 years. The independent component analysis (ICA) was used to separate occipital alpha- and mu-rhythm components and showed better performance than the channel-wise analysis. The identified mu-rhythm ICA components were localized above the left and right sensorimotor cortex, demonstrating suppression both to passive hand movement and hand movement observation and no difference in power between closed- and open-eye conditions. No interhemispheric differences were observed. The alpha-rhythm ICA components were localized in occipital regions and demonstrate characteristic suppression to open-eye conditions. The mu-rhythm frequency of peak suppression to passive hand movement as well as the amount of suppression increased with age. The beta-band mu-rhythm activity, while being less pronounced, was also suppressed both during passive hand movement and hand movement observation, while to a lesser degree than alpha-band mu during passive hand movement. Thus, we confirmed the classical properties of mu-rhythm and for the first time showed the developmental trajectory of mu-rhythm properties obtained during passive hand movement. The proposed experimental protocol and pipeline can be used further in studies of the mu-rhythm in challenging populations. • We present an inclusive paradigm to study mu-rhythm properties. • ICA allowed us to effectively separate mu- and alpha-rhythms. • Mu-rhythm in the inclusive paradigm shows classical functional properties. • Mu-rhythm frequency and suppression during passive hand movement increase with age. [ABSTRACT FROM AUTHOR]

Observing and understanding others' emotional facial expressions, possibly through motor synchronization, plays a primary role in face‐to‐face communication. To understand the underlying neural mechanisms, previous functional magnetic resonance imaging (fMRI) studies investigated brain regions that are involved in both the observation/execution of emotional facial expressions and found that the neocortical motor regions constituting the action observation/execution matching system or mirror neuron system were active. However, it remains unclear (1) whether other brain regions in the limbic, cerebellum, and brainstem regions could be also involved in the observation/execution matching system for processing facial expressions, and (2) if so, whether these regions could constitute a functional network. To investigate these issues, we performed fMRI while participants observed dynamic facial expressions of anger and happiness and while they executed facial muscle activity associated with angry and happy facial expressions. Conjunction analyses revealed that, in addition to neocortical regions (i.e., the right ventral premotor cortex and right supplementary motor area), bilateral amygdala, right basal ganglia, bilateral cerebellum, and right facial nerve nucleus were activated during both the observation/execution tasks. Group independent component analysis revealed that a functional network component involving the aforementioned regions were activated during both observation/execution tasks. The data suggest that the motor synchronization of emotional facial expressions involves a widespread observation/execution matching network encompassing the neocortex, limbic system, basal ganglia, cerebellum, and brainstem. [ABSTRACT FROM AUTHOR]

The discovery of the brain's mirror neuron system enables researchers to gain a deeper understanding of social cognitive activities from the level of neural mechanisms. Mirror neurons are situated in bilateral brain regions, overlapping with the swallowing neural network, and there are complex network pathways connecting the two. Repeatedly inducing the activation of mirror neurons in stroke patients can enhance the brain's ability to relearn its original swallowing function, and then restore the swallowing neural network. With the deepening of related studies, rehabilitation therapies based on the mirror neuron system have been discussed and explored by numerous scholars and applied to the rehabilitation of dysphagia after stroke. In this paper, we review the basic theory of mirror neuron system, its mechanism, its relevance to the swallowing neural network, and the clinical application and research progress of related rehabilitation therapies in stroke dysphagia, with a view to triggering relevant researchers to comprehend and innovate the rehabilitation of dysphagia after stroke. • Mirror neurons overlap with the swallowing neural network, and there are complex network pathways connecting the two. • Given the "observation-execution matching mechanism", reactivates the swallowing neural network, thus promoting the rehabilitation of dysphagia. • Rehabilitation therapies based on mirror neuron system have promising application prospects in improving dysphagia after stroke. [ABSTRACT FROM AUTHOR]

• The cerebellum interacts with the MNS to simulating and imitating observed actions. • Activation of MNS, prefrontal cortex, and cerebellum predicts imitation accuracy. • Bilateral cortico-cerebellar patterns improve prediction of imitation performance. • Connectivity between cerebellum, aIPS, and DLPFC enhances imitation ability. • The cerebellum plays a key role in generating predictive action representations. The ability to accurately imitate actions requires the contribution of the Mirror Neuron System (MNS) and of prefrontal and cerebellar regions. The present study aimed at investigating whether functional interaction between cortical areas and the cerebellum during the observation of complex bimanual actions can predict individual ability to imitate the same actions. Nineteen healthy participants underwent an fMRI task in which they observed complex bimanual action sequences (paper folding) and subsequently imitated the same sequences. Control conditions included passive observation of bimanual actions, observation of reaching movements, observation of actions without intent to imitate, and observation of natural landscapes. Participants' imitation performance was video-recorded and scored for accuracy. Univariate whole-brain regression, multivariate pattern recognition, and generalized psychophysiological interaction analyses were used to assess whether activation patterns during the observation phase could predict subsequent imitation performance. The results showed that: (i) observing actions during the imitation condition activated parietal, premotor, prefrontal cortex, and lateral cerebellum; (ii) activation levels in the left anterior intraparietal sulcus (aIPS), ventral premotor cortex (PMv), dorsolateral prefrontal cortex (DLPFC), and right lateral cerebellum (CB VI) predicted imitation accuracy; (iii) a bilateral distribution pattern involving aIPS, PMv, DLPFC, and CB VI better predicted imitation performance than a whole-brain approach; (iv) increased effective connectivity between the right CB VI, left aIPS, and left DLPFC during observation-to-imitate condition correlated with higher imitation accuracy. These findings underscore the role of the cerebellum within the MNS in simulating observed actions and enabling their accurate reproduction. [ABSTRACT FROM AUTHOR]

The mirror neuron system consists of fronto-parietal regions and responds to both goal-directed action execution and observation. The broader action observation network is specifically involved in observation of actions and is thought to play a role in understanding the goals of the motor act, the intention of others, empathy, and language. Many, but not all, studies have found mirror neuron system or action observation network dysfunction in autism spectrum disorder. The objective of this study was to use observation of a goal-directed action fMRI paradigm to examine the action observation network in autism spectrum disorder and to determine whether fronto-parietal activation is associated with language ability. Adolescents with autism spectrum disorder (n = 23) were compared to typically developing adolescents (n = 20), 11–17 years. Overall, there were no group differences in activation, however, the autism spectrum group with impaired expressive language (n = 13) had significantly reduced inferior frontal and inferior parietal activation during action viewing. In controls, right supramarginal gyrus activation was associated with higher expressive language; bilateral supramarginal and left pars opercularis activation was associated with better verbal-gesture integration. Results suggest that action-observation network dysfunction may characterize a subgroup of individuals with autism spectrum disorder with expressive language deficits. Therefore, interventions that target this dysfunctional network may improve expressive language in this autism spectrum subgroup. Future treatment studies should individualize therapeutic approaches based on brain-behavior relationships. [ABSTRACT FROM AUTHOR]

Mirror neurons are brain cells that are activated by the execution/observation of a movement. It has been proposed that its functions are altered in autism spectrum disorder (ASD), which is evidenced by the absence of desynchronization of the mu rhythm of the electroencephalogram when observing a biological movement, a theory known as broken mirror. The objective of this study was to test this theory in a Colombian sample. Desynchronizations of the mu rhythm of the electroencephalogram were evaluated in conditions of observation/imitation of a biological movement and in the observation of two non-biological movements in 35 cases and 19 control pairs, with ages between 6 and 16 years old. Participants with ASD presented lower desynchronizations than controls when observing/imitation of biological movement, but higher when observing inert elements. Participants with ASD established greater connection with objects than with other individuals. The broken mirror was not a homogeneous phenomenon in ASD nor a discriminating characteristic between cases and controls. Individual differences played an important role in the functioning of mirror neurons. We propose strategies based on these findings for people with Autism Spectrum Disorder in clinical, educational, productive and social contexts. [ABSTRACT FROM AUTHOR]

Observation of others' actions activates motor representations in sensorimotor cortex. Although action observation in the real-world often involves multiple agents displaying varying degrees of action involvement, most lab studies on action observation studied individual actions. We recorded EEG-mu suppression over sensorimotor cortex to investigate how the multi-agent nature of observed hand/arm actions is incorporated in sensorimotor action representations. Hereto we manipulated the extent of agent involvement in dyadic interactions presented in videos. In all clips two agents were present, of which agent-1 always performed the same action, while the involvement of agent-2 differed along three levels: (1) passive and uninvolved, (2) passively involved, (3) actively involved. Additionally, a no-action condition was presented. The occurrence of these four conditions was predictable thanks to cues at the start of each trial, which allowed to study possible mu anticipation effects. Dyadic interactions in which agent-2 was actively involved resulted in increased power suppression of the mu rhythm compared to dyadic interactions in which agent-2 was passively involved. The latter did not differ from actions in which agent-2 was present but not involved. No anticipation effects were found. The results suggest that the sensorimotor representation of a dyadic interaction takes into account the simultaneously performed bodily articulations of both agents, but no evidence was found for incorporation of their static articulated postures. [ABSTRACT FROM AUTHOR]

Action observation typically recruits visual areas and dorsal and ventral sectors of the parietal and premotor cortex. This network has been collectively termed as extended action observation network (eAON). Within this network, the elaboration of kinematic aspects of biological motion is crucial. Previous studies investigated these aspects by presenting subjects with point‐light displays (PLDs) videos of whole‐body movements, showing the recruitment of some of the eAON areas. However, studies focused on cortical activation during observation of PLDs grasping actions are lacking. In the present functional magnetic resonance imaging (fMRI) study, we assessed the activation of eAON in healthy participants during the observation of both PLDs and fully visible hand grasping actions, excluding confounding effects due to low‐level visual features, motion, and context. Results showed that the observation of PLDs grasping stimuli elicited a bilateral activation of the eAON. Region of interest analyses performed on visual and sensorimotor areas showed no significant differences in signal intensity between PLDs and fully visible experimental conditions, indicating that both conditions evoked a similar motor resonance mechanism. Multivoxel pattern analysis (MVPA) revealed significant decoding of PLDs and fully visible grasping observation conditions in occipital, parietal, and premotor areas belonging to eAON. Data show that kinematic features conveyed by PLDs stimuli are sufficient to elicit a complete action representation, suggesting that these features can be disentangled within the eAON from the features usually characterizing fully visible actions. PLDs stimuli could be useful in assessing which areas are recruited, when only kinematic cues are available, for action recognition, imitation, and motor learning. [ABSTRACT FROM AUTHOR]

• Kinematic information of PLDs grasping elicits bilateral activation of the AON. • MVPA shows decoding accuracy of both velocity and direction at the network and ROI level. • Lateral occipito-temporal and parietal areas encode both direction and velocity. • Premotor and parietal areas are involved in coding stimulus velocity. • Findings may be applied to rehabilitation programs of upper limbs motor disorders. The processing of kinematic information embedded in observed actions is an essential ability for understanding others' behavior. Previous research showed that the action observation network (AON) may encode some action kinematic features. However, our understanding of how direction and velocity are encoded within the AON is still limited. In this study, we employed event-related fMRI to investigate the neural substrates specifically activated during observation of hand grasping actions presented as point-light displays, performed with different directions (right, left) and velocities (fast, slow). Twenty-three healthy adult participants took part in the study. To identify brain regions differentially recruited by grasping direction and velocity, univariate and multivariate pattern analysis (MVPA) were performed. The results of univariate analysis demonstrate that direction is encoded in occipito-temporal and posterior visual areas, while velocity recruits lateral occipito-temporal, superior parietal and intraparietal areas. Results of MVPA further show: a) a significant decoding accuracy of both velocity and direction at the network level; b) the possibility to decode within lateral occipito-temporal and parietal areas both direction and velocity; c) a contribution of bilateral premotor areas to velocity decoding models. These results indicate that posterior parietal nodes of the AON are mainly involved in coding grasping direction and that premotor regions are crucial for coding grasping velocity, while lateral occipito-temporal cortices play a key role in encoding both parameters. The current findings could have implications for observational-based rehabilitation treatments of patients with motor disorders and artificial intelligence-based hand action recognition models. [Display omitted] This fMRI study examines how the brain encodes direction and velocity kinematic features during observation point-light displays grasping actions. Areas of the action observation network are differentially involved in coding these parameters: a) occipital and parietal areas code direction and velocity; b) parietal and dorsal premotor areas encode velocity. [ABSTRACT FROM AUTHOR]

The human mirror neuron system (MNS) can be considered the neural basis of social cognition. Identifying the global network structure of this system can provide significant progress in the field. In this study, we use dynamic causal modeling (DCM) to determine the effective connectivity between central regions of the MNS for the first time during different social cognition tasks. Sixty-seven healthy participants completed fMRI scanning while performing social cognition tasks, including imitation, empathy and theory of mind. Superior temporal sulcus (STS), inferior parietal lobule (IPL) and Brodmann area 44 (BA44) formed the regions of interest for DCM. Varying connectivity patterns, 540 models were built and fitted for each participant. By applying group-level analysis, Bayesian model selection and Bayesian model averaging, the optimal family and model for all experimental tasks were found. For all social-cognitive processes, effective connectivity from STS to IPL and from STS to BA44 was found. For imitation, additional mutual connections occurred between STS and BA44, as well as BA44 and IPL. The results suggest inverse models in which the motor regions BA44 and IPL receive sensory information from the STS. In contrast, for imitation, a sensory loop with an exchange of motor-to-sensory and sensory-to-motor information seems to exist. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Muscle weakness is a critical problem facing many older adults. Interventions targeting nervous system plasticity may show promise in enhancing strength. The purpose of this study was to examine the acute effects of action observation on muscular strength characteristics and corticospinal excitability in older adults. Isometric wrist flexion strength characteristics and corticospinal excitability of the first dorsal interosseous (FDI) were measured in 14 older adults (mean age = 73 years) in response to observation of (1) STRONG contractions of the hand/wrist, (2) WEAK contractions of the hand/wrist, and (3) a CONTROL condition. Results from repeated measures analyses of variance (ANOVAs) indicated that rate of torque development at 200 ms (RTD200) significantly decreased from PRE to POST observation for CONTROL and WEAK, but not STRONG. No other ANOVAs were significant. However, effect sizes indicated that maximal voluntary contraction (MVC) peak torque showed moderate declines following WEAK (d = − 0.571) and CONTROL (d = − 0.636), but not STRONG (d = 0.024). Similarly, rate of torque development at 30 (RTD30), 50 (RTD50), and 200 (RTD200) ms showed large declines from PRE to POST after WEAK and CONTROL, but small changes following STRONG. FDI motor-evoked potential (MEP) amplitude tended to increase over time, but these results were variable. There was a pronounced effect from PRE to 8MIN (d = 0.954) during all conditions. Action observation of strong contractions may exert a preservatory effect on muscular strength. More work is needed to determine whether this is modulated by increased corticospinal excitability. The study was prospectively registered (ClinicalTrials.gov Identifier: NCT03946709). [ABSTRACT FROM AUTHOR]

Action Observation Treatment is a novel rehabilitation approach exploiting a neurophysiological mechanism that allows one to recruit the neural structures sub-serving action execution during the mere observation of those same actions. Action Observation Treatment is effective in the rehabilitation of several neurological diseases. In this pilot study, we used Action Observation Treatment in a telerehabilitation setting in children with Cerebral Palsy. Ten children with Cerebral Palsy, aged 5–12 years, entered the study. They followed the Action Observation Treatment rehabilitation program at home with remote supervision by a child neurologist located at the hospital. Outcome measures were the scores at the Melbourne Assessment of Unilateral Upper Limb Function Scale and the Assisting Hand Assessment. Scores obtained after treatment and at a two months' follow-up significantly differed from baseline and overlapped those obtained in randomized controlled studies carried out in a conventional setting. Action Observation Treatment is therefore a promising approach that can be used on a large scale in a telerehabilitation setting. Tele-rehabilitation has the potential to enhance early intervention service provision for children with Cerebral Palsy. Action Observation Treatment has the potential to become a routine approach in a telerehabilitation setting. [ABSTRACT FROM AUTHOR]

Background: The rehabilitation of paretic stroke patients uses a wide range of intervention programs to improve the function of impaired upper limb. A new rehabilitative approach, called action observation therapy (AOT) is based on the discovery of mirror neurons and has been used to improve the motor functions of adult stroke patients and children with cerebral palsy. Recently, virtual reality (VR) has provided the potential to increase the frequency and effectiveness of rehabilitation treatment by offering challenging and motivating tasks.  METHODS: The purpose of the present project is to design a randomized controlled six-month follow-up trial (RCT) to evaluate whether action observation (AO) added to standard VR (AO + VR) is effective in improving upper limb function in patients with stroke, compared with a control treatment consisting of observation of naturalistic scenes (CO) without any action content, followed by VR training (CO + VR).Discussion: AO + VR treatment may provide an addition to the rehabilitative interventions currently available for recovery after stroke and could be utilized within standard sensorimotor training or in individualized tele-rehabilitation.Trial Registration: The trial has been prospectively registered on ClinicalTrials.gov. NCT05163210 . 17 December 2021. [ABSTRACT FROM AUTHOR]

This study aims to clarify unresolved questions from two earlier studies by McGarry et al. Exp Brain Res 218(4): 527–538, 2012 and Kaplan and Iacoboni Cogn Process 8: 103–113, 2007 on human mirror neuron system (hMNS) responsivity to multimodal presentations of actions. These questions are: (1) whether the two frontal areas originally identified by Kaplan and Iacoboni (ventral premotor cortex [vPMC] and inferior frontal gyrus [IFG]) are both part of the hMNS (i.e., do they respond to execution as well as observation), (2) whether both areas yield effects of biologicalness (biological, control) and modality (audio, visual, audiovisual), and (3) whether the vPMC is preferentially responsive to multimodal input. To resolve these questions about the hMNS, we replicated and extended McGarry et al.'s electroencephalography (EEG) study, while incorporating advanced source localization methods. Participants were asked to execute movements (ripping paper) as well as observe those movements across the same three modalities (audio, visual, and audiovisual), all while 64-channel EEG data was recorded. Two frontal sources consistent with those identified in prior studies showed mu event-related desynchronization (mu-ERD) under execution and observation conditions. These sources also showed a greater response to biological movement than to control stimuli as well as a distinct visual advantage, with greater responsivity to visual and audiovisual compared to audio conditions. Exploratory analyses of mu-ERD in the vPMC under visual and audiovisual observation conditions suggests that the hMNS tracks the magnitude of visual movement over time. [ABSTRACT FROM AUTHOR]

Interpersonal motor resonance (IMR) is a common putative index of the mirror neuron system (MNS), a network containing specialised cells that fire during both action execution and observation. Visual content inputs to the MNS, however, it is unclear whether visual behaviours mediate the putative MNS response. We aimed to examine gaze effects on IMR during action observation. Neurotypical adults (N =  99; 60 female) underwent transcranial magnetic stimulation, electromyography, and eye-tracking during the observation of videos of actors performing grasping actions. IMR was measured as a percentage change in motor evoked potentials (MEPs) of the first dorsal interosseous muscle during action observation relative to baseline. MEP facilitation was observed during action observation, indicating IMR (65.43%, SE = 11.26%, P  < 0.001). Fixations occurring in biologically relevant areas (face/hand/arm) yielded significantly stronger IMR (81.03%, SE = 14.15%) than non-biological areas (63.92%, SE = 14.60, P  = 0.012). This effect, however, was only evident in the first of four experimental blocks. Our results suggest that gaze fixation can modulate IMR, but this may be affected by the salience and novelty of the observed action. These findings have important methodological implications for future studies in both clinical and healthy populations. [ABSTRACT FROM AUTHOR]

In this study, we compared the effects of action observation therapy (AOT) on the walking ability of stroke patients between videos with limited visual attention (body part videos) and a video with the whole body (whole body video). We employed a crossover design and conducted 3 AOT sessions (body part videos, whole body video and a scenery video) for 11 stroke patients. The evaluation items were the 10-m walking time and number of steps, cadence, trunk and knee joint angles during walking, and the timed up and go test (TUGT). After body part videos, the 10-m walking time, trunk and knee joint angles and TUGT significantly improved, suggesting them to be an efficient AOT method. [ABSTRACT FROM AUTHOR]

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. • The cerebellum is connected with brain areas of the Mirror Neuron System (MNS). • The cerebellum is critically involved in Action Observation and Motor Imagery. • Cerebellar role in visuomotor matching seems crucial for shaping mirror properties. • Cerebellar modulation of cortical interneurons might affect MNS activities. • Cerebellar neuromodulation might enhance rehabilitation outcomes through the MNS. [ABSTRACT FROM AUTHOR]

Mirror neurons were discovered in macaque monkeys in the early 1990s by Rizzolatti and his colleagues at the University of Parma. In studies investigating mirror neurons in humans, noninvasive methods of neuroimaging and electrophysiology have been used because the invasive methods used on macaque monkeys are not available. Several complex functions, including identification, evaluation, and imitation of action, empathy, learning, and memory, have been attributed to this neuron group since its discovery. Thus, the mirror neuron system is thought to be the bridge between cognition and action. This possible role in cognition shows the contribution of this system in some neurological and psychiatric diseases. With this perspective, studies on the pathology of the mirror neuron system in Parkinson’s and Alzheimer’s diseases, amyotrophic lateral sclerosis, and autism-spectrum and psychotic disorders are mentioned in this review, together with research on the possible involvement of the mirror neuron system in congenital mirror movement disorder. A re-evaluation of neurological and psychiatric diseases in light of new opinions on the organization of the brain following the discovery of mirror neurons may be helpful in understanding clinical features and establishing new methods of treatment and rehabilitation. [ABSTRACT FROM AUTHOR]

Autism Spectrum Disorders (ASD) represent developmental conditions with deficits in the cognitive, motor, communication and social domains. It is thought that imitative behaviour may be impaired in children with ASD. The Mirror Neural System (MNS) concept plays an important role in theories explaining the link between action perception, imitation and social decision-making in ASD. In this study, Emergent 7.0.1 software was used to build a computational model of the phenomenon of MNS influence on motion imitation. Seven point populations of Hodgkin–Huxley artificial neurons were used to create a simplified model. The model shows pathologically altered processing in the neural network, which may reflect processes observed in ASD due to reduced stimulus attenuation. The model is considered preliminary—further research should test for a minimally significant difference between the states: normal processing and pathological processing. The study shows that even a simple computational model can provide insight into the mechanisms underlying the phenomena observed in experimental studies, including in children with ASD. [ABSTRACT FROM AUTHOR]

Neonatal imitation is widely accepted as fact and cited as evidence of an inborn mirror neuron system that underpins human social behaviour, even though its existence has been debated for decades. The possibility that newborns do not imitate was reinvigorated recently by powerful longitudinal data and novel analyses. Although the evidence is still mixed, recent research progresses the debate by ruling out some long-standing explanations for why the effect might be difficult to detect, by showing that only some research groups observe it, and by revealing indications that the published literature is biased. Further advances will be made with updated testing procedures and reporting standards, and investigation of new research questions such as how infants could learn to imitate. Although many assume that newborn infants imitate others, new data and analyses suggest it is not a reliable effect. Meta-analysis of human neonatal imitation studies revealed an overall positive effect which was not moderated by major methodological variations, but did vary by research group. Future studies of newborn imitation should adopt modern procedures to eliminate potential biases. Researchers should also test models of how imitation could be learned. Associative Sequence Learning proposes that coincident experience of producing and perceiving body gestures over the first year of life, creates mirror systems to support imitation. [ABSTRACT FROM AUTHOR]

A deficit in pre‐cognitively mirroring other people's actions and experiences may be related to the social impairments observed in autism spectrum disorder (ASD). However, it is unclear whether such embodied simulation deficits are unique to ASD or instead are related to motor impairment, which is commonly comorbid with ASD. Here we aim to disentangle how, neurologically, motor impairments contribute to simulation deficits and identify unique neural signatures of ASD. We compare children with ASD (N = 30) to children with Developmental Coordination Disorder (DCD; N = 23) as well as a typically developing group (N = 33) during fMRI tasks in which children observe, imitate, and mentalize about other people's actions. Results indicate a unique neural signature in ASD: during action observation, only the ASD group shows hypoactivity in a region important for simulation (inferior frontal gyrus, pars opercularis, IFGop). However, during a motor production task (imitation), the IFGop is hypoactive for both ASD and DCD groups. For all tasks, we find correlations across groups with motor ability, even after controlling for age, IQ, and social impairment. Conversely, across groups, mentalizing ability is correlated with activity in the dorsomedial prefrontal cortex when controlling for motor ability. These findings help identify the unique neurobiological basis of ASD for aspects of social processing. Furthermore, as no previous fMRI studies correlated brain activity with motor impairment in ASD, these findings help explain prior conflicting reports in these simulation networks. [ABSTRACT FROM AUTHOR]

Recent studies in experimental psychology revealed that a developmental correspondence exists between prediction of others' action goals and motor ability to produce the same actions. Babies interact with their environment within the first year after birth and as a result of these interactions they acquire some skills and abilities. At the same time, babies interact with other people around them and gain insight into the action goals of others. This study proposes a computational model in order to examine the developmental progression of predicting the outcome of the grasping and pushing actions on a tabletop environment. In this context, some reaching trajectories were formed towards certain objects and by combining these trajectories with the images taken from a dataset, the targeted objects, with the intention of grasping or pushing, were tried to be determined. The developmental progression for grasping and pushing actions was analyzed in four stages. The results show that the computational model can establish a direct relationship between the action recognition and the ability to predict the outcome of the actions. And the prediction ability of the grasping action was developed earlier. [ABSTRACT FROM AUTHOR]

Action observation (AO) and motor imagery (MI) are potential methods to improve various motor functions. AO and MI facilitate corticospinal excitability. Additionally, the combination of AO and MI (AO + MI) facilitates greater corticospinal excitability than AO alone. However, it is unclear whether AO + MI facilitates the excitability of spinal motor neurons better than AO alone. Thus, in this study, we compared the excitability of spinal motor neurons between AO + MI and AO conditions using F-waves. We recruited healthy adult volunteers (n = 31) for F-wave analysis. We recorded F-waves during relaxation to determine the baseline level (Rest), followed by measurement during AO and AO + MI. To counterbalance the order effect, 15 participants performed AO first, while the others performed AO + MI first. F-wave persistence was significantly increased during AO and AO + MI compared to Rest. The F-wave/M-wave amplitude ratio was significantly increased during AO + MI compared to Rest. The present results suggest that the combination of AO and MI facilitates the excitability of spinal motor neurons compared to Rest, whereas AO alone does not. [ABSTRACT FROM AUTHOR]

Objective: To investigate the clinical effects of the mirror neuron system (MNS)‐based training on upper extremity motor function and cognitive function in stroke patients. Methods: Sixty stroke patients (time from stroke onset 3–9 months) with upper extremity paresis (Brunnstrom stage II–IV) and cognitive impairment (MoCA score ≥ 15) were enrolled in this study. Patients were randomly allocated into MNS treatment group (N = 30) and control group (N = 30). Both groups underwent regular training for upper extremity motor function and cognitive function, and the MNS group was trained with a therapeutic apparatus named mirror neuron system training (MNST) including different levels of action observation training (AOT). Training lasted 20 min/day, 5 days/week for 8 weeks. MoCA, reaction time, and Wisconsin Card Sorting Test (WCST) were assessed at baseline and 8 weeks after training. Furthermore, Fugl‐Meyer assessment (FMA) and Modified Barthel index (MBI) were adopted to evaluated upper extremity motor function and daily life ability. Results: After 8 consecutive weeks' training, both groups showed significant improvements on the upper extremity motor function, cognitive function, and daily life ability score after training (p <.05). The MNS group showed significantly improved upper extremity motor function and cognitive function (p <.05) compared with control group. Conclusions: Combining MNS‐based and conventional training can improve upper extremity motor function and cognitive function in stroke patients. [ABSTRACT FROM AUTHOR]

Arterial spin labeling (ASL) is a non-invasive magnetic resonance imaging (MRI) technique that can measure regional cerebral blood flow (rCBF) without radiation exposure. This study aimed to evaluate rCBF in individuals with autism and their age-matched controls, globally and regionally. We performed ASL MRI (3 T, pulsed-continuous ASL, 3 delayed ASL imaging sequences) for 33 patients with autism spectrum disorder (ASD) (average age: 7.3 years, range: 2–14 years). Nineteen children (average age: 8.6 years, range: 3–15 years) without ASD and intellectual delay were included as controls. Patients with morphological abnormalities detected on MRI were excluded. Objective analysis was performed with automatic region of interest analysis of the ASL results. The Mann-Whitney U test was used to compare the rCBF results between the groups. Compared to the controls, patients with ASD showed a statistically significant decrease in rCBF, respectively, in the insula [left, rCBF 51.8 ± 9.5 mL/100 g/min (mean ± SD) versus 59.9 ± 9.8, p = 0.0017; right, 51.2 ± 10.1 versus 57.8 ± 8.8, p = 0.0354], superior parietal lobule (left, 44.6 ± 8.4 versus 52.0 ± 7.8, p = 0.003), superior temporal gyrus (left, 50.0 ± 8.6 versus 56.9 ± 8.6, p = 0.007; right, 49.5 ± 8.4 versus 56.4 ± 7.7, p = 0.0058), and inferior frontal gyrus (left, 53.0 ± 9.8 versus 59.3 ± 9.9, p = 0.0279), which are associated with the mirror neuron system. We concluded that patients with ASD showed a statistically significant decline in CBF in regions associated with the mirror neuron system. The advantages of ASL MRI include low invasiveness (no radiation exposure) and short imaging time (approximately 5 min). Studies with larger sample sizes are required to establish the diagnostic value of ASL MRI for ASD. [ABSTRACT FROM AUTHOR]

The mirror neuron system (MNS) becomes active during action execution and action observation, which is presumably reflected by reductions in mu (8–13 Hz) activity in the electroencephalogram over the sensorimotor cortex. The function of the MNS is still fiercely debated. The current study aimed to investigate a role of the MNS in anticipating others' actions by examining whether the MNS was activated – indexed by mu power suppression – prior to the onset of observed actions when the onset and type of action could be predicted on the basis of environmental cues. Young adults performed and observed cued grasping and placing actions in a card game in a real-life setting, while the predictability of the observed actions was manipulated using rules. Significant mu suppression, relative to within-trial baseline activity, was found both prior to and during executed actions, but also during action observation, and, crucially, prior to observed actions provided they were predictable. No anticipatory mu reductions were found prior to unpredictable observed actions. These results suggest top-down modulation of MNS activity by conceptual knowledge. This is the first study to demonstrate mu suppression prior to action onset – possibly reflecting MNS anticipatory activity – by explicitly manipulating predictability. [ABSTRACT FROM AUTHOR]

Frequently explored in macaque monkeys, the mirror neuron system (MNS) has demonstrated much influence over the development of behavioral patterns of animals. Since its discovery in macaque monkeys, research about MNS has extended to the development of humans. Researchers have deduced that the cognitive functions of MNS are essential for daily learning and social interactions such as executing imitation, understanding the actions of others, and expressing empathy. Furthermore, recent research has revealed a potential correlation between the impairment of these MNS functions in individuals diagnosed with an autism spectrum disorder (ASD). As individuals with ASD progress into adulthood, deficiencies in the functions controlled by MNS become more apparent such as socialization and communication. When individuals with ASD perform activities that are regulated by MNS functions, the putative regions of the brain where these functions are localized reveal little to no activity. Additionally, the structural development of these putative regions in ASD individuals is atypical compared to persons without ASD. Particular studies have shown simultaneous activity of another neural system, known as the mentalizing system, with that of MNS in ASD individuals. The abnormal levels of crosstalk between the MNS and the mentalizing system appears to be a direction for further analysis in ASD individuals. This review will mainly explore the relationship between emergence of ASDs from the dysfunction of the individual's MNS. [ABSTRACT FROM AUTHOR]

Motor expertise acquired during long-term training in sports enables top athletes to predict the outcomes of domain-specific actions better than nonexperts do. However, whether expert players encode actions, in addition to the concrete sensorimotor level, also at a more abstract, conceptual level, remains unclear. The present study manipulated the congruence between body kinematics and the subsequent ball trajectory in videos of an expert player performing table tennis serves. By using functional magnetic resonance imaging, the brain activity was evaluated in expert and nonexpert table tennis players during their predictions on the fate of the ball trajectory in congruent versus incongruent videos. Compared with novices, expert players showed greater activation in the sensorimotor areas (right precentral and postcentral gyri) in the comparison between incongruent vs. congruent videos. They also showed greater activation in areas related to semantic processing: the posterior inferior parietal lobe (angular gyrus), middle temporal gyrus, and ventromedial prefrontal cortex. These findings indicate that action anticipation in expert table tennis players engages both semantic and sensorimotor regions and suggests that skilled action observation in sports utilizes predictions both at motor-kinematic and conceptual levels. • Involvement of the semantic network in skilled action anticipation was examined. • Table tennis expert and nonexpert players predicted congruent or incongruent action sequences. • Functional magnetic resonance imaging assessed brain activation during an action anticipation task. • Predicting domain-specific actions involves both semantic and sensorimotor networks in experts. [ABSTRACT FROM AUTHOR]

Previous research has shown a link between eye contact and interpersonal motor resonance, indicating that the mirroring of observed movements is enhanced when accompanied with mutual eye contact between actor and observer. Here, we further explored the role of eye contact within a naturalistic two-person action context. Twenty-two participants observed simple hand movements combined with direct or averted gaze presented via a live model in a two-person setting or via video recordings, while transcranial magnetic stimulation was applied over the primary motor cortex (M1) to measure changes in M1 excitability. Skin conductance responses and gaze behavior were also measured to investigate the role of arousal and visual attention herein. Eye contact significantly enhanced excitability of the observer's M1 during movement observation within a two-person setting. Notably, participants with higher social responsiveness (Social Communication subscale of the Social Responsiveness Scale) displayed a more pronounced modulation of M1 excitability by eye gaze. Gaze-related modulations in M1 excitability were, however, not associated with differences in visual attention or autonomic arousal. In summary, the current study highlights the effectiveness and feasibility of adopting paradigms with high ecological validity for studying the modulation of mirror system processes by subtle social cues, such as eye gaze. [ABSTRACT FROM AUTHOR]

Background: Excitatory brain stimulation, in the form of intermittent theta burst stimulation (iTBS), combined with mirror visual feedback (MVF), is hypothesized to promote neuroplasticity and motor performance. Objective: This study aimed to investigate the combined effects of iTBS with mirror training (MT) on the MVF-induced sensorimotor event-related desynchronization (ERD) and the non-dominant hand motor performance in healthy adults. Methods: Eighteen healthy right-handed subjects were randomly assigned to one of three groups (Group 1: iTBS plus MT, Group 2: iTBS plus sham MT, or Group 3: sham iTBS plus MT). For participants in Groups 1 and 3, motor training was performed for 15 minutes for the right hand over four consecutive days, with MVF superimposing on their inactive left hand behind a mirror. Participants in Group 2 received the same right-hand motor training, but the mirror was covered without MVF. iTBS or sham iTBS was applied daily over the right primary motor cortex prior to the training. Electroencephalography at pre/post-training was recorded while participants performed right-hand movement under mirror and direct view. Motor performance was assessed at baseline and post-training. Results: Baseline comparisons demonstrated that a shift in sensorimotor ERD towards the right hemisphere was induced by MVF, in mu-1 (8–10 Hz) (p = 0.002), mu-2 (10–12 Hz) (p = 0.004) and beta-1 (12–16 Hz) (p = 0.049) bands. After the training, participants in Group 1 showed a stronger MVF-induced sensorimotor ERD in mu-1 (p = 0.017) and mu-2 (p = 0.009) bands than those in Group 3. No significant between-group difference in motor outcomes was observed. Conclusions: iTBS appears to prime subjects' brain to be more receptive to MVF. [ABSTRACT FROM AUTHOR]

Empathic behavior and related neural processing are strongly modified by group membership. Shared neural circuits for the production and perception of facial emotional expressions represent mirror neuron mechanisms which play a pivotal role for empathy. In this study, we investigate the influence of group membership on mirror neuron mechanisms for emotional facial expressions. In a functional magnetic resonance imaging task, 178 healthy subjects perceived emotional and neutral facial expressions of artificial ingroup and outgroup members, displayed as 5 s video clips, and produced these facial expressions themselves. Before scanning, artificial group membership was manipulated ad-hoc through a minimal group paradigm. Shared neural activity for emotional facial expression production and perception was revealed in a large network with right-hemispheric preponderance encompassing motor mirror neuron regions, i.e., inferior frontal gyrus, supplementary motor area and middle temporal gyrus, in addition to limbic regions, i.e., amygdala, hippocampus, para-hippocampus, and insula. Within this network there was greater neural activation for ingroup compared to outgroup members in temporal poles, amygdalae, the left insula, the left inferior frontal gyrus, and the inferior and middle temporal gyrus, the right hippocampus and parahippocampus. We validate and extend knowledge on brain regions with mirror neuron properties. Most crucially, we provide evidence for the influence of group membership on regions within the mirror neuron system, indicating more neural resonance (mirroring) for ingroup facial emotional expressions. • There is enhanced neural resonance (mirroring) for ingroup facial emotions. • Such ingroup bias affects amygdala, temporal pole, and hippocampus activation. • Ad-hoc created minimal group membership sufficiently induces this ingroup bias. • Knowledge about brain regions with mirror neuron properties is extended. [ABSTRACT FROM AUTHOR]

Empathy is a critical aspect of social behavior, and impairment in empathic processing is linked to hindered social interactions and several disorders. Despite much interest in this topic, our understanding of the developmental and neural involvement for empathic processing is limited. Recent evidence suggests the Mirror Neuron System (MNS) may play a role in this behavior, and that mu rhythm suppression found over the sensorimotor cortices may be a proxy for the MNS. Therefore, we aimed to measure mu rhythm oscillations in response to empathic processing during observation of painful action-based situations using electroencephalogram (EEG). Our second goal was to examine how perceived parental emotional invalidation (EI) during childhood may relate to empathy and influence mu suppression. Our results showed that mu rhythm suppression was strongest over the right hemisphere. EI had a significant influence on this suppression between painful and non-painful images, and was negatively correlated with behavioral measures of empathy. Our findings suggest that perceived childhood EI may decrease empathizing abilities and influence neural responses to the painful experiences of others. Implications from this study could entail clinical intervention targeted at emotional invalidation to foster the healthy development of empathy. [ABSTRACT FROM AUTHOR]

Abstract Language that describes actions, for instance verbs, can help to predict future actions of conspecifics in social interactions. Language and action are therefore interrelated. This interrelation has been described on a behavioral level for adults and toddlers. Furthermore, in adults, the sensorimotor system is involved in this interrelation. However, little is known about the early interrelation on the neural level at the onset of verb acquisition. In the present study, we examined the role of the sensorimotor system during the processing of acoustically presented verbs that describe dynamic actions and visually presented actions in toddlers, who are in the earliest stage of expressive language development. The activity of the sensorimotor system, in particular the suppression of the mu rhythm, was measured by means of electroencephalography (EEG). Results showed a significant suppression of the mu rhythm during both the processing of action verbs and observed actions, but not during the processing of pseudoverbs. This suggests that the sensorimotor system is already involved in the processing of action and language early in life. Highlights • Action and language processing are interrelated in adults and toddlers. • The sensorimotor system is involved in action and verb processing in adults. • We assessed the sensorimotor system's role in verb processing early in development. • We found that toddlers show sensorimotor activity for action and verb processing. [ABSTRACT FROM AUTHOR]

Objective: Echopraxia, that is, the open and automatic imitation of other peoples' actions, is common in patients with Gilles de la Tourette syndrome, autism spectrum disorder, and also those with frontal lobe lesions. While systematic reaction time tasks have confirmed increased automatic imitation in the latter two groups, adult patients with Tourette syndrome appear to compensate for automatic imitation tendencies by an overall slowing in response times. However, whether children with Tourette syndrome are already able to inhibit automatic imitation tendencies has not been investigated. Method: Fifteen children with Tourette syndrome and 15 healthy children (aged 7–12 years) performed an imitation inhibition paradigm. Participants were asked to respond to an auditory cue by lifting their index finger or their little finger. Participants were simultaneously presented with either compatible or incompatible visual stimuli. Results: Overall responses in children with Tourette syndrome were slower than in healthy children. Although responses were faster in compatible than in incompatible trials in both groups, this 'interference effect' was smaller in children with Tourette syndrome. Conclusions: Children with Tourette syndrome have a smaller interference effect than healthy children, indicating an enhanced ability to behaviourally control automatic imitation tendencies at the cost of reacting slower. The results suggest that children with Tourette syndrome already employ different or additional inhibition strategies compared to healthy children. [ABSTRACT FROM AUTHOR]

Highlights • The flickering action video with only single frequency evokes both SSVEP and the mirror neuron system simultaneously. • The mirror neuron system could be differently activated according to the contents of the flickering action video. • Our paradigm could successfully classify the LEFT, RIGHT and rest according to the contents of the flickering action video. • This paradigm has advantages in terms of the classification accuracy and the number of commands using a single frequency. • It provides potential effective BCI rehabilitation applications for people who require BCI control and MNS activation. Abstract Background The number of commands in a brain–computer interface (BCI) system is important. This study proposes a new BCI technique to increase the number of commands in a single BCI system without loss of accuracy. New method We expected that a flickering action video with left and right elbow movements could simultaneously activate the different pattern of event-related desynchronization (ERD) according to the video contents (e.g., left or right) and steady-state visually evoked potential (SSVEP). The classification accuracy to discriminate left, right, and rest states was compared under the three following feature combinations: SSVEP power (19–21 Hz), Mu power (8–13 Hz), and simultaneous SSVEP and Mu power. Results The SSVEP feature could discriminate the stimulus condition, regardless of left or right, from the rest condition, while the Mu feature discriminated left or right, but was relatively poor in discriminating stimulus from rest. However, combining the SSVEP and Mu features, which were evoked by the stimulus with a single frequency, showed superior performance for discriminating all the stimuli among rest, left, or right. Comparison with the existing method The video contents could activate the ERD differently, and the flickering component increased its accuracy, such that it revealed a better performance to discriminate when considering together. Conclusions This paradigm showed possibility of increasing performance in terms of accuracy and number of commands with a single frequency by applying flickering action video paradigm and applicability to rehabilitation systems used by patients to facilitate their mirror neuron systems while training. [ABSTRACT FROM AUTHOR]

Background: It has been hypothesised that abnormal functioning of the mirror neuron system (MNS) may lead to deficits in imitation and the internal representation of movement, potentially contributing to the motor impairments associated with developmental coordination disorder (DCD).Aims: Using fMRI, this study examined brain activation patterns in children with and without DCD on a finger adduction/abduction task during four MNS activation states: observation; motor imagery; execution; and imitation.Methods and Procedures: Nineteen boys (8.25-12.75 years) participated, including 10 children with DCD (≤16th percentile on MABC-2; no ADHD/ASD), and nine typically developing controls (≥25th percentile on MABC-2).Outcomes and Results: Even though children with DCD displayed deficits behaviourally on imitation (Sensory Integration & Praxis Test Subtests) and motor imagery assessments prior to scanning, no differences in MNS activation were seen between the DCD and control groups at a neurological level, with both groups activating mirror regions effectively across conditions. Small clusters of decreased activation during imitation were identified in non-mirror regions in the DCD group, including the thalamus, caudate, and posterior cingulate - regions involved in motor planning and attentional processes.Conclusions and Implications: The results of this study do not provide support for the MNS dysfunction theory as a possible causal mechanism for DCD. Further research to explore attentional and motor planning processes and how they may interact at a network level may enhance our understanding of this complex disorder. [ABSTRACT FROM AUTHOR]

According to the Darwinian perspective, facial expressions of emotions evolved to quickly communicate emotional states and would serve adaptive functions that promote social interactions. Embodied cognition theories suggest that we understand others' emotions by reproducing the perceived expression in our own facial musculature (facial mimicry) and the mere observation of a facial expression can evoke the corresponding emotion in the perceivers. Consequently, the inability to form facial expressions would affect the experience of emotional understanding. In this review, we aimed at providing account on the link between the lack of emotion production and the mechanisms of emotion processing. We address this issue by taking into account Moebius syndrome, a rare neurological disorder that primarily affects the muscles controlling facial expressions. Individuals with Moebius syndrome are born with facial paralysis and inability to form facial expressions. This makes them the ideal population to study whether facial mimicry is necessary for emotion understanding. Here, we discuss behavioral ambiguous/mixed results on emotion recognition deficits in Moebius syndrome suggesting the need to investigate further aspects of emotional processing such as the physiological responses associated with the emotional experience during developmental age. (A) Facial imitation therapy ‐ sinergistic activity therapy (FIT‐SAT) treatment. Each session starts with a video‐clip in which an actor remains still for 3 seconds and vocal instruction are given to the patients. Then the actor performs a smile either unilaterally (left or right side) or bilaterally. The patients are instructed to observe the video‐clip and simultaneously imitate the actor's smile. While they are smiling, the patients simultaneously clench their fist. Patients start the daily treatment with three sets of five repetitions. Progressively, further repetitions are gradually included until the patient is able to perform at least 10 successive repetitions and to maintain the smile posture for at least 3 seconds. (B) FIT combined action observation with the direct effects of action execution suggesting that the activation of motor areas by action observation becomes reinforced by the concomitant active execution of the observed actions; SAT refers to the synergistic activity of hand closing while smiling should facilitate the activation of the cortical areas connected to the mouth. The hand contraction facilitates the recruitment of the Gracilis muscle as consequence of the activity of mouth motor neurons in motor cortical areas. [ABSTRACT FROM AUTHOR]

Previous research has shown that specific goals and intentions influence a person’s allocation of social attention. From a neural viewpoint, a growing body of evidence suggests that the inferior fronto-parietal network, including the mirror neuron system, plays a role in the planning and the understanding of motor intentions. However, it is unclear whether and when the mirror neuron system plays a role in social intentions. Combining a behavioral task with electrical neuroimaging in 22 healthy male participants, the current study investigates whether the temporal brain dynamic of the mirror neuron system differs during two types of social intentions i.e., lust vs. romantic intentions. Our results showed that 62% of the stimuli evoking lustful intentions also evoked romantic intentions, and both intentions were sustained by similar activations of the inferior frontal gyrus and the inferior parietal lobule/angular gyrus for the first 432 ms after stimulus onset. Intentions to not love or not lust, on the other hand, were characterized by earlier differential activations of the inferior fronto-parietal network i.e., as early as 244 ms after stimulus onset. These results suggest that the mirror neuron system may not only code for the motor correlates of intentions, but also for the social meaning of intentions and its valence at both early/automatic and later/more elaborative stages of information processing. [ABSTRACT FROM AUTHOR]

Highlights • Greater MS activity when inferring others' intentions compared to control task. • Late timing of MS activity suggests a role in later stages of intention processing. • Predictive coding framework could explain MS and mentalizing system interactions. • Mentalizing-induced MS activation did not correlate with behavioral performance. • Mentalizing-induced MS activation did not correlate with autistic traits. Abstract Neuroimaging studies have shown mirror system (MS) activation when participants infer internal states e.g. emotions, intentions or beliefs (known as 'mentalizing') from others' actions. However, the exact role of the MS in mentalizing tasks is unknown. Dysfunctional MS activation may underlie mentalizing deficits experienced by adults with autism spectrum disorder (ASD). This study investigated the timing of MS activity when inferring intentions in order to delineate between existing models of MS involvement. Single-pulse transcranial magnetic stimulation (TMS) was applied to the primary motor cortex at different time points during the observation of hand actions whilst participants inferred intentions (mentalizing task) and performed a non-mentalizing task. Electromyographic activity in the contralateral hand was used as an indirect measure of MS activity. Greater corticospinal activity was found during the mentalizing task than the non-mentalizing task, but only at the end of observed actions, suggesting late MS involvement in processing intentions. Enhanced corticospinal activity was not related to autistic traits or behavioural performance suggesting the MS has a more automatic role in processing others' intentions, irrespective of mentalizing ability. Our results extend current knowledge of MS activation when mentalizing, allowing initial delineation between different models of MS involvement in mentalizing. [ABSTRACT FROM AUTHOR]

A great challenge for cognitive neuroscience is studying human behavior in its complexity as it manifests in the real world. The field of aviation provides a unique opportunity to investigate how perception, action and cognition interact in complex yet controlled ecologically valid environments. We suggest a novel cross-domain approach that combines insights from ecological psychology and embodied cognition with a neurophysiological framework to explain patterns of human performance across a variety of aviation contexts. Specifically, we argue that studying the interaction between an agent and the environment, as manifest in the Mirror Neuron system as a neural correlate, is key to understanding complex behavior. We can describe the experience and skills involved with task-relevant actions - like flying an airplane - using brain mechanisms of motor simulation of the observed action. With this direct coupling between perception and action, the automatic implicit nature of the Mirror Neuron system can be harnessed to improve human factor and ergonomics. This analysis offers three areas for future study and application: (1) enhancing flight training by isolating specific agent-environment relations; (2) tracking training progression based on brain signatures of flight expertise; and (3) neuroscientific-inspired ecological design of next-generation human-machine interfaces in flight decks. [ABSTRACT FROM AUTHOR]

Abstract: Cheering for another person is a common experience. Cheering may facilitate the cheerer's subjective unity with the cheered‐for person, potentially involving synchronized activity between the two individuals’ brains. In the current study, we measured the sensorimotor cortical activity of a player and an observer simultaneously during a competitive game, using functional near‐infrared spectroscopy. The player performed the rock‐paper‐scissors game against an experimenter while the observer either cheered for that player (cheering group) or judged whether the player cheated or not (control group). In the cheering group, observers reported a significantly stronger sense of unity with the player, and exhibited greater sensorimotor activation when observing the player win, compared with the control group. The functional connectivity between the sensorimotor areas of the player and observer was significantly greater in the cheering group, exhibiting a significant correlation with the subjective sense of unity between the player and observer. These results suggest that cheering enhances the synchronization of the player's and the observer's internal states, establishing a sense of unity. [ABSTRACT FROM AUTHOR]

Summary: The Mirror Neuron System (MNS) plays a crucial role in action perception and imitative behavior, which is suggested to be impaired in Autism Spectrum Disorders (ASDs). In this review, we discuss the plausibility and empirical evidence of a neural interaction between the MNS, action perception, empathy, imitative behavior, and their impact on social decision making in ASDs. To date, there is no consensus regarding a particular theory in ASDs and its underlying mechanisms. Some theories have completely focused on social difficulties, others have emphasized sensory aspects. Based on the current studies, we suggest a multilayer neural network model including the MNS on a first layer and transforming this information to a higher layer network responsible for reasoning. Future studies with ASD participants combining behavioral tasks with neuroimaging methods and transcranial brain stimulation as well as computational modeling can help validate and complement this suggested model. Moreover, we propose applying the behavioral paradigms, and the neurophysiological markers mentioned in this review article for evaluating psychiatric treatment approaches in ASDs. The investigation of modulating effects of different treatment approaches on the neurophysiological markers of the MNS can help find specific subgroups of ASDs patients and support tailored psychiatric interventions. [ABSTRACT FROM AUTHOR]

Research has demonstrated that motor control is directly influenced by observation of others’ action, stimulating the mirror neuron system. In addition, there is evidence that both emotion and empathy after observing a painful stimulus affects motor cortical excitability and reaction times. Aim of the present two pilot studies is a) to test for significant influence of observing other’s painful bending of the trunk on execution of the same activity in a self-directed bending action (study 1) and to compare these results with a bending action according to a strict bending protocol (study 2). In addition to study 1, differences between Low Back Pain (LBP) patients versus healthy subjects are tested. Video footage of a (1) neutral, (2) painful, and (3) happy bending action was presented in random order. Changes in flexion-relaxation phenomenon (FRP) of back muscles were studied directly after watching the videos with surface EMG, in study 1 during a self-directed bending action in LBP patients and healthy subjects, in study 2 according to a strict bending protocol. FRP ratios were calculated by a custom-made analysis scheme tested for sufficient reliability prior to both studies. Evoked emotions were measured with an Emotional Questionnaire after each video. A Mixed Model ANOVA was used to test for the effect video and the difference between LBP and healthy subjects on the FRP-rs. Differences in evoked emotion will be tested with a Wilcoxon Signed Rank Test. In study 1, 24 healthy controls and 16 LBP patients FRP-rs were significantly influenced after observing a painful video in all subjects versus a happy and neutral video (p = 0.00). No differences were present between LBP and healthy controls. All subjects experienced more fear after observation of the painful video (p 0.05). In study 2, 6 healthy subjects followed the strict FRP bending protocol for three times after observing each video. No significant changes occurred in FRPs per video compared to FRPs of six healthy subjects carrying out the spontaneous bending activity. Observing a painful action in another person changes motor performance and increases fear in both people with and without back pain, during self-directed trunk flexion, but not during a protocolled trunk flexion. [ABSTRACT FROM AUTHOR]