Distinguishing between self and other: How shared are shared representations? Marcel Brass

1. Distinguishing between self and other: How shared are shared representations?Marcel Brass MAX PLANCK INSTITUTE • FOR • HUMAN • COGNITIVE AND BRAIN SCIENCES • DEPARTMENT OF COGNITIVE NEUROLOGY • LEIPZIG

2. Cognitive psychology movement observation has a strong influence on movement execution (Brass et al., 2000, 2001, Stuermer et al., 2000) Social psychology chameleon effect (Chartrand & Bargh, 1999) Brain imaging activation of motor related areas by action observation (e.g. Grezes & Decety, 1999) Neurophysiology mirror neurons (e.g. Rizzolatti & Craighero, 2004) Observation and execution of action are closely linked

3. The direct matching hypothesis Action observation leads to an activation of an internal motor representation.

4. Why don‘t we imitate all the time? Why don‘t we confuse internally generated and externally triggered motor representations? Open questions

5. Luria (1966) prefrontal patients show echopractic response tendencies Lhermitte et al. (1986), DeRenzi et al. (1996) patients with prefrontal lesions show overt imitative behavior Neuropsychological findings

6. incongruent congruent baseline The imitation-inhibition task Brass et al. (2000)

7. The imitation-inhibition task Lift the index finger when a `1` appears and the middle finger when a `2` appears. + + Brass et al. (2000)

8. con base incon Results Brass et al. (2000)

9. Patients • 16 patients with frontal lesions of different etiology and lesion site • 14 patients with posterior lesions (temporal, parietal) • 16 age-matched controls

10. Imitation-inhibition task * * posterior control frontal Results interference score: incongruent errors (%) – congruent errors (%) Brass et al. (2003)

11. Conclusions • Patients with frontal lesions have problems to inhibit imitative response tendencies.

12. Functional mechanisms involved in the inhibition of imitative behavior • Hypothesis • The inhibition of imitative behavior involves general inhibitory mechanisms. • The inhibition of imitative behavior involves specific mechanisms related to the distinction of self-generated and externally triggered motor representations.

13. ten healthy right handed participants the imitation-inhibition task functional Magnetic Resonance Imaging (fMRI) Experimental design

14. 1 2 1 2 anterior fronto-median cortex (aFMC) temporo-parietal junction area (TPJ) Imitation-inhibition task Incongruent vs. congruent Brass, Derrfuss & von Cramon(2005)

15. The functional role of the anterior fronto-median cortex and the TPJ • sense of agency (e.g. Farrer et al., 2003) • perspective taking (Ruby & Decety, 2001, 2003) • out of body experience (Blanke et al., 2002)

16. Conclusions • The inhibition of imitative behaviour seems to involve mechanisms related to self-other distinction.

17. Are environmental constraints mapped onto the observer’s motor representation? The mirroring of contextual information

18. Observing a physical restraint in another person should restrain the observer. Prediction

19. Paradigm non-corresponding restraint corresponding restraint no restraint

20. Demonstration

21. Results

22. The slowing effect is due to higher perceptual difficulty in the corresponding restraint condition. Alternative hypothesis

23. Test Stimuli no restraint corresponding restraint Responses if a ‘1‘ appears if a ‘2‘ appears

24. Results

25. There is an automatic tendency to imitate observed behaviour. Prefrontal patients have problems to inhibit imitative response tendencies. The inhibition of imitative behaviour involves functional mechanisms related to self-other distinction. Not only the action itself is mapped onto the observer’s motor representation but also environmental constraints. Summary

26. Roman LiepeltStephanie SpenglerMichael SteinbornHarold BekkeringJan DerrfussWolfgang PrinzD. Yves von Cramon