S. Avikainen, R. Hari, J. Järveläinen, M. Martikainen, S. Liuhanen, M. Saarelainen, and M. Schürmann.
Visitors: K.-I. Kaneko, and 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.
We have demonstrated with MEG recordings that the human MNS comprises at least Broca's region, the primary motor cortex, the inferior parietal cortex, and the superior temporal sulcus; all these structures are activated in both hemispheres and in a nice sequence that is prolonged in its frontal part in high-functioning autistic subjecta; autism is associated with impairment in attribution of mental states and with poor imitation skills. Broca's area seems to be especially important for imitation of gestures. Interestingly, activation of Broca's area did not increase during contagious yawning compared with mouth-moving stimuli, suggesting that yawn contagiousness is a very automatic release phenomenon.
A related field of study has focused on the problem of agency: how does one know who was the agent of the motor act when both self-executed and observed movements are associated with overlapping brain activation. We have addressed the role of "efference copies" for the sense of agency: responses to simple tones were reduced when the subjects triggers them herself by a button press.