Activation of the human mirror neuron system during the observation of the manipulation of virtual tools in the absence of a visible effector limb

• Subjects manipulated virtual tools in a digital game and watched the replays.
• Virtual limbs were not necessary to produce extended mirror activity.
• M1 showed a reduced BOLD during action observation.
• Value to the field of action observation neurorehabilitation.

This work explores the mirror neuron system activity produced by the observation of virtual tool manipulations in the absence of a visible effector limb. Functional MRI data was obtained from healthy right-handed participants who manipulated a virtual paddle in the context of a digital game and watched replays of their actions. The results show how action observation produced extended bilateral activations in the parietofrontal mirror neuron system. At the same time, three regions in the left hemisphere (in the primary motor and the primary somatosensory cortex, the supplementary motor area and the dorsolateral prefrontal cortex) showed a reduced BOLD, possibly related with the prevention of inappropriate motor execution. These results can be of interest for researchers and developers working in the field of action observation neurorehabilitation.