Embodied Simulation Theory

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Embodied Simulation Theory

related brain structuresGenetics
Embodied Simulation Theoryinferior frontal gyrusDapretto etal.

Description

  • Theory

In the Theory of Embodied Simulation, the mirror neuron system plays an integral role in our ability to understand the feelings, and intentions of others because empathy and understanding the mental states of others employ mirror neuron systems. Social and communicative deficits that people with ASD experience are a result of malfunctioning mirror neuron systems.

Studies have provided evidence that there is significantly weaker activation in the inferior frontal gyrus in children with autism as compared to typically developing children. Studies also indicate that chained motor act organization is impaired in those with autism.7

The appeal of the Embodied Simulation theory for language stems from the fact that it gives a simple explanation for how empathy and feelings could be neurally coded and understood. Additionally it is parsimonious to language evolution theory and could be tested.3

  • History

Within the last 10 years Mirror Neuron Systems (MNS) have been discovered in the brain. These neurons fire both when one performs an action and when one observes another person perform the same goal-directed action.7 These systems have quickly been implicated in many higher motor functions such as action recognition, imitation, and language processing. It has been hypothesized that since the same areas of the brain are activated as seen in fMRI studies when the subjects observes the action as when they perform the action themselves, this MNS can allow us to understand the intentions of others.1

Vittorio Gallese hypothesized that it is through these mirror neuron systems where both basic forms of social cognition like empathy, and higher forms of social cognition like attribution of mental states to others and language, are constructed. Mirror neurons have also been shown to allow monkeys to anticipate the final goal of an action. Studies such as Buxbaum et. al. 2 support the notion that the neural representations of action production and action understanding are the same.3 This "understanding" of an action afforded by the activation of the mirror neuron system is proportional to the observer's own motor experiences and automatic. Recent studies have also shown that the action and motor cortical circuits in the brain are involved in the processing of language. Some hypothesize that certain premotor structures originally meant to participate in goal-related action began to be used for language.3 This hypothesis is supported by an fMRI study by Friederici et. al. that the premotor sector of the inferior frontal gyrus is activated during the processing of language.5

Similarly in humans, it has been hypothesized that the MNS is involved in social cognition, language and imitation learning and ASD patients have shown to have deficits in imitation and forming "theory of mind". This has be proved with EEG studies. MNS also have greater impact on development of children as children learn through imitation and other peoples actions. This ability to imitate is affected with a dysfunctional MNS. In one hypothesis, children with a dysfunctional MNS correspondingly have a deficient audiovisual to motor link, which results in deficient language and communication, thus affecting the formation of Theory of Mind.6

EEG studies have shown that actions children with ASD, had MNS system activate (has greater mu suppression) when the actions were performed by them or when they observe actions performed by some one familiar to them, they did not respond well to actions performed by strangers. So its important for kids with ASD to have more interactions with family members and familiar individuals.6


Human Mirror System Organization

In Humans the Mirror system gets activated is composed of the inferior parietal lobule (IPL) and the premotor cortex, and the caudal part of the inferior frontal gyrus (IFG) roughly corresponding to the pars opercularis of Broca’s area. These regions form the core of the human parieto-frontal mirror system.

Brain Imaging studies using transcranial magnetic stimulation (TMS), recorded the motor-evoked potentials (MEPs) and found the activation of motor cortex during action observation, which indicates the presence of Mirror system. Further the Mu rhythm, a rhythm recorded in the correspondence of the cortical motor areas and known to desynchronize during movement execution, also desynchronizes during the observation of actions carried out by others. Following the discovery of mirror neurons, several studies repeated these experiments confirming the desynchronization of Mu rhythm during action observation.


Continued....
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Citations

1. Buccino, G. et. al. Mirror Neurons and the Understanding of Behavioural Symptoms. Curr Opin Psychiatry. 2008 May;21(3):281-5. PMID 18382228

2. Buxbaum et. al. On beyond mirror neurons: internal representations subserving imitation and recognition of skilled object-related actions in humans. Brain Res Cogn Brain Res. 2005 Sep;25(1):226-39.PMID 15996857

3. Gallese, V. Before and below 'theory of mind':embodied simulation and the neural correlates of social cognition. Philos Trans R Soc Lond B Biol Sci. 2007 Apr 29;362(1480):659-69. PMID 17301027

4. Buccino et. al. Listening to action-related sentences modulates the activity of the motor system: a combined TMS and behavioral study. Brain Res Cogn Brain Res. 2005 Aug;24(3):355-63. Epub 2005 Apr 12. PMID 16099349

5. Friederici et. al. The brain differentiates human and non-human grammars: functional localization and structural connectivity. Proc Natl Acad Sci U S A. 2006 Feb 14;103(7):2458-63. Epub 2006 Feb 6 PMID 16461904

6. Le Bel, RM et. al. Motor-auditory-visual integration: The role of the human mirror neuron system in communication and communication disorders. J Commun Disord. 2009 Apr 17. PMID 19419735

7. Rizzolatti G et. al. Mirror neurons: from discovery to autism.Exp Brain Res. 2010 Jan;200(3-4):223-37. PMID 19760408