Parietal cortex damage impairs skill acquisition via motor imagery

We learn and strengthen skills by repeatedly practicing a task. Activity in our brain changes as we practice, which ultimately leads to learning the skill. However, we do not actually have to perform the task to learn the skill. Instead we can imagine ourselves performing the task without moving, which is called motor imagery. When we practice using motor imagery, similar brain areas are activated as in actual performance. Recently, there has been an increased interest to use motor imagery in addition to physical practice to help recover lost functions after stroke. However, a certain brain area is commonly damaged after stroke that needs to be active during both real and imagined practice. To use motor imagery in stroke rehabilitation, we must therefore ensure that damage to this brain area does not impact on practicing skills using motor imagery. To study this, we looked at this brain area to figure out its role when motor imagery is used to practice and learn a new skill. We used a machine that lets us temporarily 'shut-off' certain brain areas safely. Using this machine allowed us to mimic brain damage, mirroring what we observe after stroke. People with and without this temporary brain damage tried to learn a new skill using motor imagery. We demonstrated that the ability to learn the new skill was affected by the brain damage. This research ultimately contributes to using motor imagery for recovery after stroke by helping us identify which patients may be able to use motor imagery for stroke rehabilitation.