Mirrored high gamma cortical activity during finger tap imitation

The discovery of mirror neuron system in the macaque study in the 1990s explored a new way to investigate motor imitation. By using the electrocorticographic (ECoG) with high resolution in both spatial and temporal domains, this paper studies brain function during both observation and execution of a simple finger tapping task. Four epilepsy patients were asked to watch simple finger tapping video clips and then imitate the same action themselves. A significant mirrored power increase in the high gamma (HG) band (> 60Hz) have been observed over the superior parietal cortex in the right hemisphere. Furthermore, the power changes in the frequency range 75-95Hz were phase locked to the finger tapping trajectory. The temporal patterns of ECoG power varied during observation and execution, and were similar with the neuronal firing histogram recorded in the macaque imitation study.