C534 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

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 IMITATE LATER

Table 1 Five scanning conditions repeated in each subject Nature of the stimuliTask instruction Abbreviatio n Stationary hands Observation without any purposeS Learned meaningless movements Observation without any purposeLM Unknown meaningless movements Observation without any purposeUM Learned meaningless movementsObservation to imitateLMi Unknown meaningless movementsObservation to imitateUMi

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, Intention to Imitate Common area for all conditions Viewing hand movements

Imitating 2x2 factorial from visual and motor aspects of imitation Body schema: Use same limb as model Action: Make same movement Interaction = motor mimicry, true imitation Chaminade et al (2005) Neuropsychologia 43,

How do we know that mirror system activity in man reflects motor rather than sensory representation? Alternatives –Viewing body scheme? –Objects/affordances?

Non-expert Watching actions you can do or can’t do… Subjects Ballet dancers Capoeira dancers Dance videos BalletCapoeira Expert

Expert - non-expert Experts show more mirror system brain activity than non- experts Mirror neuron areas Calvo-Merino et al Cerebral 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 Motor familiarity

Female Male Female Visual familiarity Motor familiarity Visual familiarity Motor familiarity Subjects ‘Gender specific’ actions ‘Common’ motor actions

Pure motor familiarity effect Mirror neuron areas

Object-action transformation Rumiati et al Neuroimage 2004 Interaction: Pantomime/Object Imitate/name