Mirror Neuron Mechanism Research Articles

Social intuition: behavioral and neurobiological considerations.

Social intuition is instrumental in bringing about successful human interactions, yet its behavioral and neural underpinnings are still poorly understood. We focus in this article on the automatic, involuntary, nature of social intuition, rather than on higher-level cognitive and explicit Theory-of-Mind processes (which contribute to rendering social intuition meaningful in real-life situations). We argue that social-affective implicit learning plays a crucial role in establishing automatic social intuition. These implicit learning processes involve associations between the perception of other's bodily articulations, concurrent events, and the consequences or outcomes in terms of subsequent actions, affective valences and visceral states. The traditional non-social implicit learning paradigms do not allow one to draw conclusions about the role of implicit learning processes in social intuition, as they lack these vital characteristics typically associated with human actions. We introduce a new implicit learning paradigm, which aims to fill these gaps. It targets agile, rapid, social-affective learning processes, involving cue contingencies with a relatively simple structure, unlike the very complex structures that underpin the traditional tasks. The paradigm features matching social and non-social versions, allowing direct comparison. Preliminary data suggest equal performance of TD (typically-developed) and ASC (autism spectrum conditions) groups on the non-social version, but impaired implicit learning in ASC on the social version. We hypothesize that this reflects an anomalous use of implicitly learned affective information in ASC when judging other people. We further argue that the mirror neuron mechanism (MNM), which is part of the Action Observation Network, forms an integral part of the neural substrate for social intuition. In particular as there are indications that the MNM supports action anticipation, and that implicitly learned information can trigger MNM activation, which both seem vital to a social intuition ability. The insights that can be derived from comparing the performances of TD and ASC individuals on (non)social implicit learning tasks, and the implications for the role of MNM activation, are discussed.

Grapho-motor imitation training in children with handwriting difficulties: A single-center pilot study

Imitation is a crucial process for learning and brain development. It is based on the mirror neuron mechanism and underlies our understanding of actions and the gestures of others. Some researchers hypothesized a possible correlation between a low functioning mirror neuron system (MNS) and developmental coordination disorder, including dysgraphic deficit. However, no studies have verified whether imitation of graphic gestures by exploiting the properties of the MNS could improve handwriting. This study evaluates the effects of imitation training of handwriting in five children with handwriting difficulties aged 8 to 10 years. The training lasted for five months, and was undertaken three times a week, for a total number of 60 sessions for each child. Before and after the training, we evaluated the degree of handwriting impairment using the Concise Evaluation Scale for Children’s Handwriting (BHK). Our results suggest that handwriting imitation training produced a significant qualitative change in the children’s writing, likely due to exercises that stimulated fine motor imitation. Furthermore, the imitation also involved ergonomic and biomechanical aspects relevant to improving imitative writing after observing the model. Each child has therefore reached an adequate level of writing, suggesting the effectiveness of the proposed intervention.

Imitative Collaboration: A mirror-neuron inspired mixed reality collaboration method with remote hands and local replicas

Mixed reality can overlay and display 3D digital content in the real world, convey abstract concepts to users, and promote the understanding of complex tasks. However, the abstract graphics overlaid on the physical space may cause a certain cognitive load for local users and reduce the efficiency of collaboration. To improve the efficiency of remote collaboration, we conducted an elicitation study on assembly tasks, explored the user needs for collaboration, and defined the design goals of our remote collaboration method. Inspired by the mirror-neuron mechanism, we present an imitative collaboration method that allows local users to imitate the interaction behavior of remote users to complete tasks. We also propose a series of interaction methods for remote users to select, copy, and interact with the local point clouds to facilitate the expression of collaboration intentions. Finally, the results of a user study evaluating our imitative collaboration method on assembly tasks are reported, confirming that our method improves collaboration efficiency while reducing the cognitive load of local users.

The Effects of Speed-Modulated Visual Stimuli Seen through Smart Glasses on Work Efficiency after Viewing.

It is known that subjective time and work efficiency are affected by visual stimuli. However, existing studies only consider the effects of visual information on the user during viewing and ignore the after effects. Using smart glasses lets users see visual information while moving until just before arriving at the office or school. We hypothesize that the user’s effects from the visual information they were looking at just before working or studying affects the subsequent work. Through two user studies, we investigated whether information presented on smart glasses affected subsequent work efficiency. In the first experiment, participants were presented with avatars running at two levels of speed, or no avatars, through simulated smart glasses in a virtual environment. They then solved a dot-clicking task on a desktop monitor. In the second experiment, we investigated whether the same effect could be shown while walking in the real environment, with a running and a fast-walking avatar both at the same speed in order to see the difference in the effects of the different movements. In the first experiment, we confirmed that the speed of later work tended to improve when presenting the running human-shaped avatar. From the results of the second experiment, which was conducted in the real environment, we did not confirm that the subsequent work speed varied depending on the type of avatar being displayed. As a reason for the trend of improvement in the task efficiency in the first experiment, observation of fast human motion may have unconsciously accelerated the observers’ body movement speed due to the mirror neuron mechanism. As a reason for why the work speed did not improve in the second experiment, the participants may be affected by other pedestrians and running cars. Additionally, it was difficult to see the images on the smart glasses while walking in the real environment.

Playful interactions and facial mimicry in infant bonobos (Pan paniscus)

The capacity to promptly and congruently respond to others’ facial signals has at its basis a mirror neuron mechanism. In Rapid (< 1 sec, RFM) and Delayed (1–5 sec, DFM) Facial Mimicry the expression emitted by an individual (trigger) is perceived and replicated by an observer. The occurrence of mimicry phenomena has been demonstrated almost exclusively in the play domain. Here, we aim at evaluating the presence of RFM/DFM during playful interactions between infant bonobos (Pan paniscus), one of the most playful primate species. We video-recorded 435 play sessions between five infants (< 48 months of age) belonging to the bonobo colony hosted at the Wilhelma Zoo (Germany). Via a frame-by-frame video-analysis, we demonstrated the presence of both RFM and DFM. These two phenomena were enhanced by face-to-face interactions between playmates. Hence, the access to others’ faces allows the player to perceive, decode and replicate signals, thus promoting a mutual intersubjective engagement with the partner. The occurrence of DFM suggests that in bonobos, as in chimpanzees, such mirror event is present just starting from infancy. The less automaticity characterizing DFM compared to RFM could be due to the involvement of more complex and time-demanding cognitive processes. Neither RFM nor DFM increased the duration of play sessions. Probably, the mimicry phenomena in infant bonobos are not recruited for manipulating the sessions, which are highly balanced and fair, but possibly for sharing the playful mood between interacting subjects thus increasing their level of familiarity and affiliation.

Functional Lateralization of the Mirror Neuron System in Monkey and Humans

To date, both in monkeys and humans, very few studies have addressed the issue of the lateralization of the cortical parietal and premotor areas involved in the organization of voluntary movements and in-action understanding. In this review, we will first analyze studies in the monkey, describing the functional properties of neurons of the parieto-frontal circuits, involved in the organization of reaching-grasping actions, in terms of unilateral or bilateral control. We will concentrate, in particular, on the properties of the mirror neuron system (MNS). Then, we will consider the evidence about the mirror neuron mechanism in humans, describing studies in which action perception, as well as action execution, produces unilateral or bilateral brain activation. Finally, we will report some investigations demonstrating plastic changes of the MNS following specific unilateral brain damage, discussing how this plasticity can be related to the rehabilitation outcome

Emotion specific neural activation for the production and perception of facial expressions

The distinction between different facial emotions is crucial for interpersonal communication. Shared neural circuits for facial emotion production and perception are considered to facilitate the ability to understand other's emotional state via mirror neuron mechanisms. Little is known about how diverse emotions differentially activate the Mirror Neuron System (MNS) during facial expression processing. In a functional magnetic resonance imaging (fMRI) task, 178 healthy subjects perceived and produced emotional (happy vs angry) and non-emotional (lip-protrusion vs no movement) facial expressions. Dynamic facial expressions were displayed as 5 sec video clips. We identified three overlapping networks of neural activation for happy, angry, and non-emotional (lip-protrusion) facial expression production and perception. Importantly, this overlap was largely due to the common motor component of facial expressions. However, for happy facial expressions, we found specific MNS activation in the right temporal pole. For angry facial expressions we found such activation in the left inferior frontal gyrus, pars orbitalis, and the cerebellum (lobules VII and VIII). We extend knowledge on mirror neuron mechanisms as our results provide evidence for emotion specific shared neural activation for the production and perception of facial emotions. This emotion specific representation of other's emotion in one's own neural production system might facilitate understanding of other's mental or emotional states.

Intergroup empathy: Enhanced neural resonance for ingroup facial emotion in a shared neural production-perception network

IntroductionEmpathic 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. MethodsIn 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. ResultsShared 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. DiscussionWe 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.

Mirror and (absence of) counter-mirror responses to action sounds measured with TMS.

To what extent is the mirror neuron mechanism malleable to experience? The answer to this question can help characterising its ontogeny and its role in social cognition. Some suggest that it develops through sensorimotor associations congruent with our own actions. Others argue for its extreme volatility that will encode any sensorimotor association in the environment. Here, we added to this debate by exploring the effects of short goal-directed ‘mirror’ and ‘counter-mirror’ trainings (a ‘mirror’ training is defined as the first type of training encountered by the participants) on human auditory mirror motor-evoked potentials (MEPs). We recorded MEPs in response to two tones void of previous motor meaning, before and after mirror and counter-mirror trainings in which participants generated two tones of different pitch by performing free-choice button presses. The results showed that mirror MEPs, once established, were protected against an equivalent counter-mirror experience: they became manifest very rapidly and the same number of training trials that lead to the initial association did not suffice to reverse the MEP pattern. This steadiness of the association argues that, by serving direct-matching purposes, the mirror mechanism is a good solution for social cognition.

Empathy-Related Responses to Depicted People in Art Works.

Existing theories of empathic response to visual art works postulate the primacy of automatic embodied reaction to images based on mirror neuron mechanisms. Arguing for a more inclusive concept of empathy-related response and integrating four distinct bodies of literature, we discuss contextual, and personal factors which modulate empathic response to depicted people. We then present an integrative model of empathy-related responses to depicted people in art works. The model assumes that a response to empathy-eliciting figural artworks engages the dynamic interaction of two mutually interlinked sets of processes: socio-affective/cognitive processing, related to the person perception, and esthetic processing, primarily concerned with esthetic appreciation and judgment and attention to non-social aspects of the image. The model predicts that the specific pattern of interaction between empathy-related and esthetic processing is co-determined by several sets of factors: (i) the viewer's individual characteristics, (ii) the context variables (which include various modes of priming by narratives and other images), (iii) multidimensional features of the image, and (iv) aspects of a viewer's response. Finally we propose that the model is implemented by the interaction of functionally connected brain networks involved in socio-cognitive and esthetic processing.

The role of mirror neuron mechanisms in the anticipation of others’ actions in relation to autistic traits: An EEG study

The role of mirror neuron mechanisms in the anticipation of others’ actions in relation to autistic traits: An EEG study

Motor control may support mirror neuron research with new hypotheses and methods: Reply to comments on “Grasping synergies: A motor-control approach to the mirror neuron mechanism”

Motor control may support mirror neuron research with new hypotheses and methods: Reply to comments on “Grasping synergies: A motor-control approach to the mirror neuron mechanism”

The mirror neuron analogy: Implications for rehabilitation neuroscience: Comment on “Grasping synergies: A motor-control approach to the mirror neuron mechanism” by A. D'Ausilio et al.

The mirror neuron analogy: Implications for rehabilitation neuroscience: Comment on “Grasping synergies: A motor-control approach to the mirror neuron mechanism” by A. D'Ausilio et al.

The granularity of grasping: Comment on “Grasping synergies: A motor-control approach to the mirror neuron mechanism” by A. D'Ausilio et al.

The idea that mirror neuron systems in the human and the macaque monkey could provide a link between perceiving an action and performing it has spurred intense research [1,2]. Hundreds of papers now examine if this link exists and what it might contribute to human behaviour. The review article from D’Ausilio et al. [3] highlights how relatively few papers have considered the granularity of coding with mirror neuron systems, and even fewer have directly tested different possibilities. Granularity refers to the critical question of what actually is encoded within the mirror system – are neurons selective for low level kinematic features such as joint angle, or for postural synergies, or for action goals? Focusing on studies of single neurons in macaques and on studies measuring the excitability of primary motor cortex with TMS, the review suggests that it is very hard to distinguish low-level kinematic from goal representations. Furthermore, these two levels are often highly correlated in real-life contexts – the kinematics needed to grasp an apple are defined by the shape of the goal (an apple tends to be a large sphere) and these kinematics differ for other possible goals (a pencil which is a narrow cylinder). In some cases, kinematics may be enough to define a goal [4]. The review suggests that it is therefore arbitrary to distinguish these levels, and that a synergy level might be a better way to understand the mirror system. Synergies are a form of coding based on commonly used hand-shapes or hand postures, which take into account the fact that some joint angles are more likely to co-occur than others. Evidence that different grasp shapes are represented separately in premotor cortex has been found [5]. These could provide an intermediate level of representation between muscle activity and goals. The review proposes that a synergy level of granularity provides the best way to consider both the motor system and the role of the mirror system in understanding actions. This is a useful proposal, but has some limitations. The proposed synergies seem much closer to a kinematic representation than to goals, and do not necessarily resolve the problem of if/how the mirror neuron system could contribute to understanding goals. Just because it is not easy to separate cognitive concepts such as kinematics and goals, does not mean it should not be done. A small number of carefully designed fMRI experiments have been able to show distinct patterns of brain activity for goals and kinematics. For example, grasping a tennis ball and grasping an apple both involve the same hand kinematics and the same hand synergies, but quite different goals. Anterior intraparietal sulcus can distinguish these actions [6] and shows cross-modal sensitivity to other action goals too [7].

From muscles synergies and individual goals to interpersonal synergies and shared goals: Mirror neurons and interpersonal action hierarchies: Comment on “Grasping synergies: A motor-control approach to the mirror neuron mechanism” by D'Ausilio et al.

From muscles synergies and individual goals to interpersonal synergies and shared goals: Mirror neurons and interpersonal action hierarchies: Comment on “Grasping synergies: A motor-control approach to the mirror neuron mechanism” by D'Ausilio et al.

The role of synergies within generative models of action execution and recognition: A computational perspective: Comment on “Grasping synergies: A motor-control approach to the mirror neuron mechanism” by A. D'Ausilio et al.

Controlling the body – given its huge number of degrees of freedom – poses severe computational challenges. Mounting evidence suggests that the brain alleviates this problem by exploiting “synergies”, or patterns of muscle activities (and/or movement dynamics and kinematics) that can be combined to control action, rather than controlling individual muscles of joints [1–10]. D’Ausilio et al. [11] explain how this view of motor organization based on synergies can profoundly change the way we interpret studies of action recognition in humans and monkeys, and in particular the controversy on the “granularity” of the mirror neuron system (MNs): whether it encodes either (lower) kinematic aspects of movements, or (higher) goal representations, or both but at different hierarchical levels [12]. Here we offer a complementary, computational perspective on the role of synergies for action recognition and the MNs. In computational modeling and robotics, it is widely assumed that a control scheme using synergies simplifies movement planning and execution. This scheme permits to use elemental behaviors or primitives as “building blocks” to be composed (e.g., combined linearly, sequenced) to produce more complex behaviors, thus controlling relatively few degrees of freedom [13–15]. Do synergies yield equivalent benefits for action recognition? To answer this question from a computational viewpoint, we frame the concept of synergies within generative architectures of action execution and recognition [16–20]. According to two leading theories of motor control, optimal feedback control [21] and active inference [22], the motor system can be conceptualized as a (hierarchical) generative model, which encodes a (probabilistic) mapping between “task goals” specified at a higher level (e.g., grasping a cup) and states of the “plant” to be controlled (i.e.,

The cortical mirror system reflects the cortical motor system: Comment on “Grasping synergies: A motor-control approach to the mirror neuron mechanism” by A. D'Ausilio et al.

The cortical mirror system reflects the cortical motor system: Comment on “Grasping synergies: A motor-control approach to the mirror neuron mechanism” by A. D'Ausilio et al.

Granularity of the mirror neuron system: A complex endeavor: Comment on “Grasping synergies: A motor-control approach to the mirror neuron mechanism” by A. D'Ausilio et al.

Granularity of the mirror neuron system: A complex endeavor: Comment on “Grasping synergies: A motor-control approach to the mirror neuron mechanism” by A. D'Ausilio et al.

Toward a functional account of the human mirror system: Comment on “Grasping synergies: A motor-control approach to the mirror neuron mechanism” by A. D'Ausilio et al.

Toward a functional account of the human mirror system: Comment on “Grasping synergies: A motor-control approach to the mirror neuron mechanism” by A. D'Ausilio et al.

The (un)coupling between action execution and observation: Comment on “Grasping synergies: A motor-control approach to the mirror neuron mechanism” by D'Ausilio, Bartoli and Maffongelli

When we observe actions performed by others, our motor system resonates along with that of the observed agent [1]. The exact features of this resonant motor response, however, are unclear. Do we mirror the goal of others' actions or rather the low-kinematic features of their movements? D'Ausilio et al. suggest that this is an ill-defined problem: the mirror system plausibly replicates the same computational mechanisms implicated by motor control. Accordingly, motor synergies may not only constitute a pervasive element of motor control, but also form the fundamental unit of action observation.