Brain activity during motor imagery of an action with an object: A functional magnetic resonance imaging study

• We examined the effect of holding an object on brain activity during motor imagery.
• Subjects imagined squeezing a ball (7 cm) with or without holding the ball.
• Holding the object during imagery increased the activity of front-parietal network.

We utilized functional magnetic resonance imaging to investigate the brain regions activated during motor imagery of an action with an object both with and without passively holding the object. Participants performed the following tasks: (1) ‘Imagery with Ball’ condition: subjects imagined squeezing a foam ball (7 cm diameter) while holding the ball, (2) ‘Imagery’ condition: subjects imagined squeezing a ball without holding the ball, and (3) ‘Ball’ condition: subjects held the ball without motor imagery. Regions activated by the ‘Imagery with Ball’ condition were located in the left dorsolateral prefrontal cortex (DLPFC), supplemental motor areas (SMA), inferior parietal lobule (IPL), superior parietal lobule (SPL), insula, cerebellum and basal ganglia. A direct comparison revealed that the right DLPFC and the right IPL showed a higher level of activation during the ‘Imagery with Ball’ than during the ‘Imagery’ + ‘Ball’ conditions. Our studies suggested that the right front-parietal networks were involved in the motor imagery of an action with an object.