Social Cognition 3: Mirror Neurons

Who discovered mirror neurons and when?

Rizzolati (1992)

How were mirror neurons initially discovered?

In monkeys

How were they discovered in monkeys?

When one monkey reached for food, certain neurons fired in the other monkey’s premotor cortexs solely from observing the action

Why are they labelled ‘mirror neurons’?

Because the neurons ‘mirror’ the motor activity seen in another individual

What is meant by ‘mirroring’?

The same neurons are active both when the individual performs an action and when they observe someone else performing it

Gallese & Goldman (1998)

Proposed mirror neurons respond to more than observed actions but they respond to the intentions behind the behaviour

Involvement of the motor system in understanding goals of others

We stimulate other’s actions with out own motor system

Involvement of mirror neurons in understanding goals of others

Using mirror neurons to ‘experience’ actions internally, we can understand the intended goal or intentionality of others

Human perspective taking

By firing in response to other’s actions & intentions, they provide a neural mechanism for understanding another person’s perspective and emotional state

Significance of human perspective taking

Allows humans to interpret what others are thinking and feeling

What is Ramachandran’s (2011) view focus on?

Shaping human evolution and understanding humans as a social species

What is Ramachandran’s (2011) view?

Mirror neurons are necessary for enabling uniquely complex social interactions and allow humans to live in large groups with complex social roles and rules that characterise human culture

Who proposed the ‘broken mirror’ theory?

Ramachandran and Oberman (2006)

What is the broken mirror theory?

The idea that neurological deficits prevent a developing child from imitating and understanding social behaviour in othersW

What are the neurological deficits in the broken mirror theory?

Dysfunction in the mirror neuron system

What does the broken mirror theory explaib?

Autism

How does the neural dysfunction manifest in infancy?

Children later diagnosed with autism typically mimic adult behaviour less than their peers.

How does the neural dysfunction manifest in childhood?

Challenges in social communication

How do challenges in social communication impact the child?

Because the child does not fully develop the ability to read the intentions & emotions of others

Mukamel et al. (2010)

Single-unit recordings in epilepsy patients’ surgery

Mukamel et al. (2010) study

Recorded activity from individual neurons in the brains of epilepsy patients undergoing surgery

Mukamel et al. (2010) findings

One neuron increased its firing both when the participant observed and executed smiling and frowning

When did the neuron not fire in Mukamel et al.’s (2010) study

Not during hand-grip or control conditions

What do the findings in Mukamel et al. (2010) study suggest?

That there’s mirror-like neural activity in humans , with this neuron appearing to be selective for facial expressions.

What is the evidence for mukamel et al.’s (2010) study?

Increased activity from neurons in the entorhinal cortex (temporal lobe) under the conditions of a smile and frown being observed and executed but not in the precision grip or whole hand grip

Why does Mukamel et al. (2010) matter?

Closest thing to direct mirror neuron evidence in humans. The neurons were found in areas beyond the classic motor regions where mirror neurons were identified in monkeys.

What did Iacoboni et al. (2005) study?

fMRI responses when a subject watched people perform an action & inferred their intention

Findings Iacoboni et al. (2005)

Activity was increased in Broca’s area & the premotor cortex when subjects inferred intention

Evidence Iacoboni et al. (2005)

Intention was inferred by presenting a grasping action within different visual contexts, (clean or messy table) so participants could judge whether the person was grasping the cup in order to drink or to clean up.

Why does Iacoboni et al. (2005) study matter?

Moved beyond simple action observation & argued that mirror neurons contribute to social cognition by coding the ‘why’ behind actions.

Muthukumaraswamy & Johnson (2004)

Mu rhythm desynchronization when humans observe actions through EEGs

Muthukumaraswamy & Johnson (2004)’s study

Used EEG to measure mu rhythm (8-13 Hz) activity over the sensorimotor cortex while participants watched videos of hand movements

Mu activity

Seen at rest, so less mu activity indicated cortical activity

Muthukumaraswamy & Johnson (2004) findings

Observing biological hand movements led to mu desynchronisation, a pattern also associated with movement execution

Positives with mu activity’s association with motor neurons

Mu desynchronisation means a reduction in sensorimotor alpha waves (8-13 Hz), it happens during both movement & action observation, its used as a possible indirect measure of mirror neuron activity in humans

Problems with mu activity’s association with motor neurons

Not definite proof- other motor processes could explain it

Why does Muthukumaraswamy & Johnson (2004) matter?

Indirect evidence that the human motor system is activated during action observation, aligning with the mirror neuron hypothesis

Haker et al. (2012)

Used fMRI to show that activation in the inferior frontal gyrus during contagious yawning- a basic form of empathy, area rich in mirror neurons

Hadjikhani (2007)

Found a smaller inferior frontal gyrus volume in autistic individuals

Dapretto et al. (2006)

Observed reduced activation in this region (smaller inferior frontal gyrus) during emotional face processing in children with autism

Hamilton (2013)

Imaging evidence was inconsistent & difficult to interpret

Slack (2007) real-world applications

Proposed that it may be possible to help autistic individuals through strengthening the motor neurons using activities that require the imitation of others- such as interventions aimed at strengthening neural function

Positive A03

Motor neuron hypothesis in explaining autism is the identification of structural and functional anomalies in brain regions linked to the mirror neuron system

Strength A03

Research robustly links them to crucial aspects of social cognition

Limitation A03

Studying these neurons in humans is inherently challenging due to the reliance on non-invasive imaging techniques

Limitation Iacoboni et al. (2005)

fMRI studies which track blood oxygenation rather than individual cell activity

Limitation of Mukamel et al. (2010)

Although it is a more direct measurement & provided evidence of mirror neuron activity in facial expressions- studies are rare as they involve pre-surgical epileptic patients which makes them difficult to generalise as they have a neurological condition.

Limitation of Muthukumaraswamy & Johnson (2004)

Lack the required spatial resolution to confirm cellular activity