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Lecture 8: Action observation and the human ‘mirror system’

Mirror neurons

The neuron is activated by “seeing” someone else’s hand performing a manipulative action and while the monkey is performing the same action

A mirror neuron is a motor neuron that “recognizes” gestures

A mirror neuron is a motor neuron that “recognizes” gestures

• Action Understanding– Communication,

culture, empathy, theory of mind

• Imitation– Innate ability?– How useful is imitation

without the above?

Umilta et al, (2001) Neuron

Meaningful actions

Decety & Grezes 99

JUST WATCH

WATCH AND IMITATELATER

Table 1 Five scanning conditions repeated in each subject

Nature of the stimuli Task instruction Abbreviation

Stationary hands Observation without any purpose S

Learned meaningless movements Observation without any purpose LM

Unknown meaningless movements Observation without any purpose UM

Learned meaningless movements Observation to imitate LMi

Unknown meaningless movements Observation to imitate UMi

The effects of learning and intention on the neural network involved in the perception of meaningless actions

J. Grèzes. N Costes and J. Decety Brain, Vol. 122, No. 10, 1875-1887

+Intention to Imitate

Common area for all conditionsViewing hand movements

Imitating

2x2 factorial from visual and motor aspects of imitationBody schema: Use same limb as modelAction: Make same movementInteraction = motor mimicry, true imitation

Chaminade et al (2005)Neuropsychologia43, 115-127

• How do we know that mirror system activity in man reflects motor rather than sensory representation?

• Alternatives– Viewing body scheme?– Objects/affordances?

Non-expert

Non-expert

Watching actions you can do or can’t do…

Subjects

Ballet dancers

Capoeira dancers

Dance videosBallet Capoeira

Expert

Expert

Expert - non-expert

Experts show more mirror system brain activity than non-experts

Mirror neuron areas

Calvo-Merino et alCerebral Cortex (2005)In press

Visual vs. motor experience

Set of gender-specific ballet moves

Subjects

Female dancers

Female moves

Male dancers

Male moves

Visual familiarity

Visual familiarity

Visual familiarity

Visual familiarity

Motor familiarity

Motor familiarity

Fem

ale

Female

Mal

e

Male MaleFemale

Visual familiarity

Visual familiarity

Visual familiarity

Visual familiarity

Motor familiarity

Motor familiarity

Visual familiarity

Visual familiarity

Visual familiarity

Visual familiarity

Motor familiarity

Motor familiarity

Motor familiarity

Motor familiarity

Su

bje

cts

‘Gender specific’ actions

‘Common’ motor actions

Pure motor familiarity effect

Mirror neuron areas

Object-action transformation

Rumiati et alNeuroimage 2004

Interaction:Pantomime/ObjectImitate/name