The authors' aim in this study was to consider the functional equivalence of internal imagery, external imagery, and action execution. Sixteen elite gymnasts imaged and performed a complex gymnastic vault. Ten performers imaged from an internal perspective, and 6 used an external perspective. Although the results revealed that the time to image the entire motor task did not significantly differ from the time required to physically perform it, irrespective of the imagery perspective used, the temporal organization of the action was different within the imagery conditions than it was in the physical condition. The results do not provide support for the principle of temporal functional equivalence. The authors discuss the results in light of recent findings from the cognitive neuroscience and psychology literatures.

The aim of this study was to test the validity of mirror neuron activity in humans through analysis of electroencephalographic (EEG) functional connectivity during an action not directed towards an object. We investigated changes in EEG interchannel synchronization prior to and during action execution and also prior to and during observation of the same action. Twelve participants observed a simple finger movement sequence. In a second testing session they physically executed the movement. EEGs were recorded from 19 active sites across the cortex. Activity was considered in four frequency bands (7-10 Hz, 10-13 Hz, 13-20 Hz, and 20-30 Hz) using a new measure: synchronization likelihood. This technique considers rapid changes in signal synchronization and spatiotemporal patterns of coherence. The results revealed no statistically significant difference in synchronization likelihood between the observation and execution data. We found an increase in synchronization over a broad frequency range during task processing and suggest that this may reflect interregional cortical coupling of intricately and hierarchically interconnected networks that are active in a similar way during both observation and execution of a movement. While EEG may be insensitive to differences present during the observation and execution of a movement, the results of the present study shed some light on the general mechanisms of cognitive integration.

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