Action imagery combined with action observation activates more corticomotor regions than action observation alone.

BACKGROUND AND
PURPOSE: Both action observation (AO) and action imagery have been proposed as therapeutic options for stroke rehabilitation. Currently, it is not clear to what extent their underlying neuronal mechanisms differ from each other and whether one of these therapeutic options might be preferable for this purpose.
METHODS: Twenty-six neurologically healthy subjects were investigated using functional magnetic resonance imaging during AO alone and during AO with additional action imagery of video clips showing simple, object-related hand actions.
RESULTS: The blood oxygenation level dependent (BOLD) signal induced by AO increased in a bihemispheric, symmetrical network of areas including the occipital, superior, and inferior parietal cortex, dorsal and ventral premotor regions, and the prefrontal cortex. The addition of imagery to the AO elicited additional activation in both cerebellar hemispheres, caudate nucleus, ventral and dorsal premotor cortex, inferior parietal cortex, and the supplementary motor area. DISCUSSION AND
CONCLUSION: These data reveal more profound activations of the motor system during AO in conjunction with imagery than during AO alone. These results may have important implications for neurorehabilitation and motor learning.