Mirror neuron brain regions contribute to identifying actions, but not intentions

Previous studies have struggled to determine the relationship between mirror neuron brain regions and two distinct “action understanding” processes: identifying actions and identifying the intentions underlying those actions. This may be because the identification of intentions from others' actions requires an initial action identification process. Disruptive transcranial magnetic stimulation was administered to left inferior frontal gyrus (lIFG) during a novel cognitive task to determine which of these “action understanding” processes is subserved by mirror neuron brain regions. Participants identified either the actions performed by observed hand actions or the intentions underlying those actions. The extent to which intention identification was disrupted by lIFG (vs. control site) stimulation was dependent on the level of disruption to action identification. We subsequently performed functional magnetic resonance imaging during the same task. During action identification, responses were widespread within mirror neuron areas including lIFG and inferior parietal lobule. However, no independent responses were found in mirror neuron brain regions during intention identification. Instead, responses occurred in brain regions associated with two distinct mentalizing localizer tasks. This supports an account in which mirror neuron brain regions are involved in an initial action identification process, but the subsequent identification of intentions requires additional processing in mentalizing brain regions

Mirror Neurons and Empathy - A Biomarker for the Complementary System

openThe discovery of the mirror neuron system gave rise to many new paths within neuroscience, psychology, kinematics and philosophy. This neurological system helped foster a broader understanding of social interaction, as these neurons fire in action observation and action performance. To this day, it is identified that the mirror neuron system is related to action understanding, comprehension of other’s intentions and the ability to recognise another person’s mental state. Furthermore, a link between the mirror neuron system, empathy and prosocial behaviour is also well-established, whereas the complementary system enables us to understand and complete other individual’s actions. Hence, the objective of this study was to assess the relationship between the mirror neurons system, trait empathy and the ADM muscle activation in a complementary action setting, which is strongly related to the grasping movement within these contexts. Results revealed a relationship between low empathic traits and muscle activation in non-social conditions, suggesting that individuals scoring low on empathy seem less willing to help other people in a complementary action interplay.The discovery of the mirror neuron system gave rise to many new paths within neuroscience, psychology, kinematics and philosophy. This neurological system helped foster a broader understanding of social interaction, as these neurons fire in action observation and action performance. To this day, it is identified that the mirror neuron system is related to action understanding, comprehension of other’s intentions and the ability to recognise another person’s mental state. Furthermore, a link between the mirror neuron system, empathy and prosocial behaviour is also well-established, whereas the complementary system enables us to understand and complete other individual’s actions. Hence, the objective of this study was to assess the relationship between the mirror neurons system, trait empathy and the ADM muscle activation in a complementary action setting, which is strongly related to the grasping movement within these contexts. Results revealed a relationship between low empathic traits and muscle activation in non-social conditions, suggesting that individuals scoring low on empathy seem less willing to help other people in a complementary action interplay

Action-Perception Matching in Human Cultural Evolution: Updates from the Cognitive Science Debate

Analyses of action-perception matching mechanisms, such as the Mirror Neuron System (MNS), have been prominent in evolutionary accounts of human cognition. Some scholars have interpreted data on the MNS to suggest that the human capacity to acquire and transmit cultural information is a learned product of cultural evolution (the Culture not Biology Account of cultural learning). Others have interpreted results related to the MNS to suggest that cultural learning in humans result from both cultural and biological evolution (the Culture per biology Account of cultural learning). In this paper, we analyse action-perception matching mechanisms considering evolutionary models and novel experimental findings about the MNS. We review the Culture not biology account plausibility within evolutionary theory and argue that as it stands this account is theoretically unsound. We finally argue for the plausibility of the Biology per culture account and discuss how it paves the way to further neurobiological investigations about the evolution of our capacity to learn, understand and transmit cultural information

Predicting Empathy From Resting State Brain Connectivity: A Multivariate Approach.

Recent task fMRI studies suggest that individual differences in trait empathy and empathic concern are mediated by patterns of connectivity between self-other resonance and top-down control networks that are stable across task demands. An untested implication of this hypothesis is that these stable patterns of connectivity should be visible even in the absence of empathy tasks. Using machine learning, we demonstrate that patterns of resting state fMRI connectivity (i.e. the degree of synchronous BOLD activity across multiple cortical areas in the absence of explicit task demands) of resonance and control networks predict trait empathic concern (n = 58). Empathic concern was also predicted by connectivity patterns within the somatomotor network. These findings further support the role of resonance-control network interactions and of somatomotor function in our vicariously driven concern for others. Furthermore, a practical implication of these results is that it is possible to assess empathic predispositions in individuals without needing to perform conventional empathy assessments

Mind and Brain States

With neurons emergence, life alters itself in a remarkable way. This embodied neurons become carriers of signals, and processing devices: it begins an inexorable progression of functional complexity, from increasingly drawn behaviors to the mind and eventually to consciousness [Damasio, 2010]. In which moment has awareness arisen in the history of life? The emergence of human consciousness is associated with evolutionary developments in brain, behavior and mind, which ultimately lead to the creation of culture, a radical novelty in natural history. It is in this context of biological evolution of conscious brains that we raise the question: how conscious brains connect with each other? In order to answer it, I will explore how brain states and conscious states each participate in dynamic interactive processes involving the whole organism. I will argue that a possible way to overcome the hard problem of consciousness might be based on the notion of embodiment as a process of embedding the mental in the living organism relating dynamically with the environment through the sensorymotor experience. In order to do so, I will provide an assembly between an anthropologic perspective of consciousness with contemporary Philosophy of Mind, Interaction Theory [Gallagher 2001, 2008; Zahavi 2001, 2008; Fuchs and De Jaegher 2009]

Brain and behavioral correlates of action semantic deficits in autism.

Action-perception circuits containing neurons in the motor system have been proposed as the building blocks of higher cognition; accordingly, motor dysfunction should entail cognitive deficits. Autism spectrum conditions (ASC) are marked by motor impairments but the implications of such motor dysfunction for higher cognition remain unclear. We here used word reading and semantic judgment tasks to investigate action-related motor cognition and its corresponding fMRI brain activation in high-functioning adults with ASC. These participants exhibited hypoactivity of motor cortex in language processing relative to typically developing controls. Crucially, we also found a deficit in semantic processing of action-related words, which, intriguingly, significantly correlated with this underactivation of motor cortex to these items. Furthermore, the word-induced hypoactivity in the motor system also predicted the severity of ASC as expressed by the number of autistic symptoms measured by the Autism-Spectrum Quotient (Baron-Cohen etal., 2001). These significant correlations between word-induced activation of the motor system and a newly discovered semantic deficit in a condition known to be characterized by motor impairments, along with the correlation of such activation with general autistic traits, confirm critical predictions of causal theories linking cognitive and semantic deficits in ASC, in part, to dysfunctional action-perception circuits and resultant reduction of motor system activation

Reduced connectivity between mentalizing and mirror systems in autism spectrum condition

The mentalizing system and mirror system are thought to play important roles in inferring the internal mental states of others – a process known as mentalizing. Autism spectrum condition (ASC) is associated with difficulties in mentalizing. The aim of this study was to determine whether the behavioural difficulties in mentalizing associated with ASC can be explained by changes in functional connectivity between the mentalizing and mirror system. We recruited 40 adult participants (20 with ASC and 20 typically-developing). Brain activity was monitored using functional magnetic resonance imaging while participants watched videos in which actors performed hand actions. The videos were shown in separate mentalizing and non-mentalizing blocks. During mentalizing blocks, participants were asked to indicate whether hand actions were clumsy or spiteful (i.e. to judge the intent of the action). During non-mentalizing blocks, participants indicated whether the actions were successful or unsuccessful (i.e. to judge the outcome of the action). Higher activity during the mentalizing blocks compared to non-mentalizing blocks was found in regions associated with the mentalizing system: the dorsal medial prefrontal cortex (dmPFC) and the temporo-parietal junction (TPJ), as well as in regions typically associated with the mirror system: the inferior frontal gyrus (IFG) and the inferior parietal lobe (IPL). Next, functional connectivity between regions was evaluated as a function of task. During mentalizing blocks, there was increased functional connectivity between the dmPFC and the mirror system in typically developing participants. In contrast, there was no increase in functional connectivity between these regions in ASC participants. Connectivity between the dmPFC and IFG was negatively correlated with autistic traits. The reduced connectivity in ASC participants was consistent with behavioural performance on the mentalizing task, which was also negatively correlated with the level of autistic traits. Together, these data emphasise the importance of functional connectivity between the mentalizing and mirror systems when inferring social intentions and show that reduced connectivity between these systems may explain some of the behavioural difficulties experienced by adults with ASC

What can autism teach us about the role of sensorimotor systems in higher cognition? New clues from studies on language, action semantics, and abstract emotional concept processing.

Within the neurocognitive literature there is much debate about the role of the motor system in language, social communication and conceptual processing. We suggest, here, that autism spectrum conditions (ASC) may afford an excellent test case for investigating and evaluating contemporary neurocognitive models, most notably a neurobiological theory of action perception integration where widely-distributed cell assemblies linking neurons in action and perceptual brain regions act as the building blocks of many higher cognitive functions. We review a literature of functional motor abnormalities in ASC, following this with discussion of their neural correlates and aberrancies in language development, explaining how these might arise with reference to the typical formation of cell assemblies linking action and perceptual brain regions. This model gives rise to clear hypotheses regarding language comprehension, and we highlight a recent set of studies reporting differences in brain activation and behaviour in the processing of action-related and abstract-emotional concepts in individuals with ASC. At the neuroanatomical level, we discuss structural differences in long-distance frontotemporal and frontoparietal connections in ASC, such as would compromise information transfer between sensory and motor regions. This neurobiological model of action perception integration may shed light on the cognitive and social-interactive symptoms of ASC itself, building on and extending earlier proposals linking autistic symptomatology to motor disorder and dysfunction in action perception integration. Further investigating the contribution of motor dysfunction to higher cognitive and social impairment, we suggest, is timely and promising as it may advance both neurocognitive theory and the development of new clinical interventions for this population and others characterised by early and pervasive motor disruption

Neurale Netzwerke der Selbst- und Fremdrepräsentation und deren Integrität bei Schizophrenie

Die erfolgreiche Teilnahme an sozialen Interaktionen innerhalb unserer Gesellschaft ist für das Überleben unerlässlich. An zugrunde liegende Prozesse muss unser Gehirn bestens angepasst sein. Allerdings gehören gestörte soziale Kognitionsfähigkeiten bei der Schizophrenie zur Kernsymptomatik (Frith, 1992). In der vorliegenden Dissertation wurden die Prozesse im Gehirn von Patienten mit Schizophrenie sowie im nicht-pathologischen Gehirn untersucht, die an sozialen Kognitions-Fähigkeiten beteiligt sind. Dazu wurden drei funktionelle Magnetresonanz-Tomographie (fMRT) Studien durchgeführt, die sich mit (1) der Wahrnehmung von Kooperation, (2) der Wahrnehmung eigener sowie fremder Handlungen und (3) der Unterscheidung eigener und fremder Handlungen beschäftigen. Die Wahrnehmung von Kooperation als Form der sozialen Interaktion wurde bisher nur selten untersucht. Zusätzlich ist bekannt, dass Betroffene ein verändertes Kooperationsverhalten zeigen (z. B. Wischniewski et al., 2009) und unter Verfolgungswahn leiden. Um einen möglichen Zusammenhang zwischen defizitärer Wahrnehmung sozialer Interaktion und der Wahnsymptomatik zu untersuchen, wurde ein fMRT Paradigma entwickelt, bei dem Videos beobachtetet wurden, bei denen zwei Darsteller kooperativ bzw. alleine Objekte manipulieren. Anschließend wurde der Zusammenhang der individuellen Ausprägung von Verfolgungswahn mit der Gehirnaktivierung untersucht. Bei Patienten mit Schizophrenie werden soziale Kognitions-Defizite oft mit einer Störung des Spiegelneuronensystems (MNS) erklärt. Dieses Netzwerk ist gleichermaßen aktiviert, wenn Handlungen beobachtet sowie selbst ausgeführt werden (z. B. Iacoboni et al., 2005). Ein einfaches fMRT-Paradigma ermöglichte die Untersuchung der Integrität des MNS bei Schizophrenie: Abwechselnd wurden Videos von Greifbewegungen beobachtet und im Anschluss wiederholt. Neben der Untersuchung von Aktivierungsunterschieden, wurden Konnektivitätsanalysen durchgeführt. Wenn „selbst“ und „fremd“ im MNS gleichermaßen abgebildet werden, bedarf es eines Kontrollsystems, das zwischen beidem unterscheiden kann, um Urheberschaftszuweisungen zu gewährleisten. Bei Patienten mit Schizophrenie gelingt dies nicht immer fehlerfrei. Es wird angenommen, das eine Störung des Efferenzkopie-Mechanismus, der motorische Handlungspläne mit sensorischen Handlungskonsequenzen auf neuraler Ebene vergleicht, dafür verantwortlich ist (z. B. Blakemore et al., 2000). Um sich der Funktionsweise dieses Prozesses anzunähern, wurde die Gehirnaktivität in Folge kontinuierlicher Greifbewegungen untersucht. Abwechselnd wurde das visuelle Feedback dieser Bewegungen zeitlich verzögert. Dies führte zu einer Diskrepanz zwischen motorischen Handlungsplänen und den wahrgenommenen sensorischen Handlungskonsequenzen. In Studie #1 konnte gezeigt werden, dass sich das Aktivierungsmuster des Netzwerks für die Kooperationswahrnehmung bei Patienten mit Schizophrenie genau entgegengesetzt zu gesunden Probanden darstellte. Teile des Kooperations-Netzwerks von Patienten zeigten geringere Aktivität im kooperativen Kontext und signifikant stärkere Aktivierung während Videoszenen ohne Kooperation. Diese Hyperaktivierung stand im Zusammenhang mit der individuellen Ausprägung des Verfolgungswahns. Mit diesen Ergebnissen können wir neue experimentelle Belege für die Theorie eines überaktivierten Mentalisierungs-Netzwerks und Hypermentalisierungs-Tendenzen (z. B. Abu-Akel & Bailey, 2000) bei Patienten mit Schizophrenie liefern. Die Ergebnisse von Studie #2 legen nahe, dass eine ausgedehnte Dyskonnektivität des MNS für soziale Defizite bei Patienten mit Schizophrenie verantwortlich ist. Solche Defizite könnten auf einem gestörten Feedback-Austausch innerhalb dieses Systems basieren. In Studie #2 wird diskutiert, ob die neue Erkenntnis einer der Hauptgründe für die verminderte soziale Funktionsfähigkeit von Patienten ist. In der dritten Studie konnte der inferiore frontale Gyrus (IFG) als potentieller Kandidat für einen Kontrollmechanismus innerhalb des MNS identifiziert werden. Bei gesunden Probanden gewährleistet er durch seine Antwortcharakteristik eine Unterscheidung zwischen „selbst“ und „nicht-selbst“. Bei Patienten war die Aktivität in diesem System allerdings in einer Art verändert, die nahelegt, dass der IFG das neurale Korrelat eines defizitären Efferenzkopie-Mechanismus darstellt. Zusätzlich war die funktionelle Konnektivität des IFG zu anderen Teilen des „Self-Monitoring“-Netzwerks vermindert, wodurch der essentielle Austausch von Abgleichssignalen zwischen motorischen und sensorischen Arealen im Gehirn beeinträchtigt sein könnte. Ein Zusammenhang zwischen den Veränderungen innerhalb dieses Netzwerks mit der Ausprägung der Ich-Störungen konnte hier gezeigt werden. Zusammenfassend könnten diese Veränderungen zu den „Self-Monitoring“-Defiziten führen, die zur Kernsymptomatik der Schizophrenie beitragen

Neural mechanisms of social cognition – the mirror neuron system and beyond

In my PhD thesis, I present three functional magnetic resonance imaging studies aimed at investigating neurobiological mechanisms underlying social cognition. My thesis focuses on fast and automatic processes that are proposed to build the basis of social understanding, and might be activated in parallel to more effortful deliberate mechanisms. The proposed neural substrate of fast and automatic processes are mirror neurons, which according to the theory of embodied simulation allow humans to understand other individuals’ actions, and even emotions and intentions. Since non-invasive techniques cannot be applied to measure mirror neurons, but only neural populations assumed to constitute the mirror neuron system, experimental paradigms and analysis routines that allow approximation of mirror neuron functions need to be developed. In study 1, I demonstrated that different social cognitive skills, including imitation, affective empathy and theory of mind share a common neural basis, located in regions associated with the mirror neuron system. In addition to standard analyses, a shared voxel analysis was applied that revealed common activation for social-cognitive processes not only across, but also within participants. Study 2 was set up to investigate whether the mirror neuron system can distinguish the valence of facial configurations. The use of a functional magnetic resonance imaging adaptation paradigm allowed to determine neural populations sensitive to emotional valence. While the fusiform gyrus was sensitive to changes from fearful to smiling faces and also from smiling to fearful faces, Brodmann area 44 reaching into insula, and superior temporal sulcus, i.e. regions more commonly associated with the mirror neuron system and with the so called mentalizing network, showed particularly increased activation for switches from smiling to fearful faces. Study 3 was dedicated to the investigation of decision making in the context of ambiguous facial configurations. While probabilistic decision making on these facial configurations lead to activation in the executive control network, final decisions for an emotion resulted in nucleus accumbens activation. In addition, perceiving fear in a face lead to higher nucleus accumbens activation during final decisions than perceiving happiness. This finding can be linked to salience processing in the nucleus accumbens. In conclusion, all three studies show an involvement of fast and automatic processing regions for different social-cognitive processes. Study 3 additionally examined the interaction with slower and more deliberate processes, as involved in probabilistic decision making on ambiguous faces. The mirror neuron system seems to be critically involved in different social-cognitive tasks and also sensitive to emotional valence. In cases when automatic processing is not possible, as when presented with ambiguous facial configurations, brain regions commonly associated with probabilistic decision making assist, and the nucleus accumbens, possibly by directing salience, is involved in the final decision. These results deepen the understanding of the mechanisms of social cognition and encourage the use of sophisticated methods in experimental paradigms and analysis