Abstract
The mirror neuron system has been suggested to play a role in many social capabilities such as action understanding, imitation, language and empathy. These are all capabilities that develop during infancy and childhood, but the human mirror neuron system has been poorly studied using neurophysiological measures. This study measured the brain activity of 6-month-old infants and adults using a high-density EEG net with the aim of identifying mirror neuron activity. The subjects viewed both goal-directed movements and non-goal-directed movements. An independent component analysis was used to extract the sources of cognitive processes. The desynchronization of the mu rhythm in adults has been shown to be a marker for activation of the mirror neuron system and was used as a criterion to categorize independent components between subjects. The results showed significant mu desynchronization in the adult group and significantly higher ERP activation in both adults and 6-month-olds for the goal-directed action observation condition. This study demonstrate that infants as young as 6 months display mirror neuron activity and is the first to present a direct ERP measure of the mirror neuron system in infants.
Acknowledgements
This study was supported by grants (KR) from the Swedish Research Council (421–2003–1508) and the EU integrated project FP6–004370 (Robotcub).
The author acknowledges the contribution of Robert Oostenveld for making the DIPFIT software available, as well as the whole EEGLAB developer group. Luciano Fadiga and Laila Craighero contributed with valuable discussions and Claes von Hofsten, Kerstin Rosander and Clara Schmitow assisted with important improvements and great support.