This recent study demonstrated the effects of watching someone else at a motor planning level in the brain. The movement that we actually make involves the brain making a plan and then executing this plan by sending signals down the spinal cord and out to the muscles (the muscular system is basically told what to do in terms of tension and contraction/relaxation). Hence, a movement is only as good as the plan. The plan does however, rely on a good accurate body schema (body awareness constructed by all the sensory information coming from the body) and accurate sensory information coming from the body. This is often disrupted in chronic pain and requires re-training with specific techniques.
We have some understanding of mirror neurons and how they are activated in the brain when we observe meaningful movement. Using this system in a rehabilitation process is useful as a way of reducing the threat (rehearsal, similar to that if you were preparing for a speech) and hence sensitivity and aversion to movement or a body part (that feeling of ‘ugggh’ when a fork screeches across a plate), and to begin the development of discrete and precise motor control. Normal motor control is arguably important in the process of desensitisation as there is one less reason for the neuroimmune system to protect the body.
I often use observational training with patients as a way of rehabilitating the motor system. This piece of work adds data and valuable support for its use as we can further understand the effects upon the brain.
Modulating the Motor System by Action Observation After Stroke.
Garrison KA, Aziz-Zadeh L, Wong SW, Liew SL, Winstein CJ.
BACKGROUND AND PURPOSE:
Much recent interest surrounds the use of action observation, which is observing another individual performing a motor task, in stroke rehabilitation, to promote motor recovery by engaging similar brain regions to action execution. This may be especially useful in individuals with limited mobility. Here, we assess how cortical motor activity during action observation is affected by stroke and by stroke-related motor deficits.
We used functional MRI to compare brain activity during right and left hand action observation in right-handed nondisabled participants and participants who were right-handed before left hemisphere stroke. All participants performed the same actions after their functional MRI.
Nondisabled participants show greater bilateral cortical motor activity when observing actions made using the left hand, whereas participants with stroke show greater ipsilesional cortical motor activity when observing actions made using the right (paretic) hand (P<0.05; corrected). For both groups, action processing is modulated by motor capability: cortical motor activity is greater when observing the hand with lower motor scores (P<0.05; corrected). Furthermore, for stroke, the extent of ipsilesional activity correlates with lesion volume (P=0.049), in a pattern that suggests adaptive plasticity.
We found that action observation activates specific motor plans in damaged motor circuits after stroke, and this activity is related to motor capability to perform the same actions. Cortical motor activity during action observation may be relevant to motor learning, and to motor relearning in stroke rehabilitation.