Cooperation in Mind: Motor imagery of joint and single actions is represented in different brain areas

In this study brain activity during motor imagery (MI) of joint
actions, compared to single actions and rest conditions, was investigated
using functional magnetic resonance imaging (fMRI). To the best of our
knowledge, this is the first neuroimaging study which directly
investigated the neural correlates of joint action motor imagery. Twenty
one healthy participants imagined three different motor tasks (dancing,
carrying a box, wiping). Each imagery task was performed at two kinds:
alone (single action MI) or with a partner (joint action MI). We
hypothesized that to imagine a cooperative task would lead to a stronger
cortical activation in motor related areas due to a higher vividness and
intensification of the imagery. This would be elicited by the integration
of the action simulation of the virtual partner to one´s own action.
Comparing the joint action and the single action condition with the rest
condition, we found significant activation in the precentral gyrus and
precuneus respectively. Furthermore the joint action MI showed higher
activation patterns in the premotor cortex (inferior and middle frontal
gyrus) compared to the single action MI. The imagery of a more vivid and
engaging task, like our joint action imagery, could improve
rehabilitation processes since a more distributed brain activity is
found. Furthermore, the joint action imagery compared to single action
imagery might be an appropriate BCI task due to its clear spatial
distinction of activation.