Brain basis of social interaction

R. Hari, L. Helle, J. Järveläinen, K.-I. Kaneko, M. Martikainen, T. Morita, M. Saarelainen, and M. Schürmann

Visitor: N. Nishitani (Tokorozawa, Japan).

Collaborators:

Proper interpretation of the intentions of our fellow human beings is an essential ability for successful communication in the society. Recent research suggests that the mirror-neuron system (MNS), first discovered in monkeys, is important for such social cognition. The MNS is activated both when the subject views another person performing motor acts and when he himself performs similar movements. The MNS therefore could form the basis for understanding the intentions of other persons and be a good candidate for the neurophysiological locus of disorders resulting in difficulties of smooth and reciprocal social communication, such as in autism and schizophrenia. However, the motor MNS might be just the tip of an iceberg among various mirroring systems that allow people to interact with each other in an understanding, predictive, and emphatic manner. Our aim is to strenghen studies of social interaction within this framework.

We have demonstrated with MEG recordings a considerable delay in the MNS activation sequence in highly-functioning asperger subjects who also have difficulties in imitation and action understanding; the delay indicates abnormalities in the connection between the inferior parietal lobe (that is important for coding motor actions and for addressing intentions) to the inferior frontal gurus (“Broca’s area” that is the human homologue of the monkey mirror-neuron area F5 and an important action–perception interface, also relevant for goal setting).

Interestingly the inferior frontal gyrus did not show any extra activation during contagious yawning, indicating that it is important only for imitation of new skills, not for release of stereotypic contagious motor patterns.

In monkeys, the mirror neurons are not activated by tool use. In contrast, we showed that the human primary motor cortex is activated when the subjects observe goal- and no-goal-directed chopstick use; the effect was stronger for the goal-directed movements. Interestingly, the effect at the motor cortex was the stronger the more experience the subjects themsevels had about chopstick use. This important finding is the first one to indicate that the MNS is shaped by experience.

 Publications

  1. Hari R: Assessing mind by reading brain and body during social interaction; Thoughts about human mirroring systems. In Braaten S (Ed): “Foundations of (pre)verbal intersubjectivity in light of new findings”. Theory Forum Symposium in The Norwegian Academy of Science and Letters. Olso, Norway, October 2004
  2. Hari R and Nishitani N: From viewing of movement to imitation and understanding of other persons’ acts: MEG studies of the human mirror-neuron system. In N Kanwisher and J Duncan (Eds) Functional Neuroimaging of Visual Cognition. Attention and Performance XX. Oxford University Press, Oxford 2004, pp. 463–479.
  3. Järveläinen J, Schürmann M and Hari R: Activation of the human primary motor cortex during observation of tool use. Neuroimage 2004, 23: 187–192.
  4. Järveläinen J, Schürmann M, Avikainen S, Cannon TD, Lönnqvist J, Huttunen M and Hari R: Disease-specific decrease in reactivity of the primary motor cortex during action observation and execution in twins discordant for schizophrenia. Submitted.
  5. Martikainen MM, Kaneko K and Hari R: Responses to self-triggered sounds are suppressed in the human auditory cortex. Cerebral Cortex 2005, 15: 299–302
  6. Möttönen R, Järveläinen, J Sams M and Hari R: Viewing speech modulates activity in the left SI mouth cortex. Neuroimage 2005, 24: 731–737.
  7. Nishitani N, Avikainen S and Hari R: Abnormal imitation-related cortical activation sequences in Asperger’s syndrome. Ann Neurol 2004, 55: 558–562.
  8. Nishitani N, Schürmann M, Amunts K and Hari R: Broca’s region: From action to language. Physiology (Bethesda) 2005, 20: 60–69.
  9. Schürmann M, Hesse MD, Stephan KE, Saarela M, Zilles K, Hari R and Fink GR: Yearning to yawn: Brain correlates of yawn observation. Neuroimage 2005, 24: 1260-1264.