There are some oversights when it comes to traditional rehabilitation therapies when compared to advances in neuroscience research. The idea of focusing on muscles instead of the brain, doing mindless repetitions to create “muscle memory” will only provide limited outcomes.
The whole idea of thinking in terms of muscle memory instead of the brain is backwards. There is no question that to be able to move, we need our muscles, and that stronger muscles provide us with the possibility for stronger, more powerful movement and stamina.
However, muscles do not know what to do on their own. It is the brain that “tells” the muscles what to do—when to contract and when to let go—through the signals it sends to the muscles. And in order for the brain to know what signals to send to our muscles, it has to first “know” that the muscles are there to be used and learn how to coordinate the different muscle groups successfully. The brain needs a rich variety of experiences from which it creates the necessary connections and patterns of our movements, also known as “mapping” in the brain. When a child has cerebral palsy and not muscular dystrophy – they have nothing wrong with their muscles, they have a brain injury and need to learn their muscles exist. That happens through self exploration using approximation and variation not repetition.
Brain research has shown that movement done automatically does not create new connections in the brain, but rather it grooves in more deeply existing brain patterns (those stubborn limitations, making the limitations and poorly organized movement more pronounced instead of introducing proper function). However, the moment we bring attention to what we feel as we do any movement, there is an immediate, dramatic increase in the number of new connections associated with the areas of body that we are moving.
Research shows that movement done automatically creates little or no new connections in the brain:
“[T]he variable determining whether or not the brain changes is . . . the attentional state of the animal.” Schwartz J, Begley S. 2002, rpnt 2003.
The Mind and the Brain: Neuroplasticity and the Power of Mental Force. New York: HarperCollins. Recanzone G. H, Merzenich MM, Jenkins WM, et al. 1992.
Topographic reorganization of the hand representation in cortical area 3b of owl monkeys trained in a frequency discrimination task. Journal of Neurophysiology 67: 1031-56. Nudo RJ, Milliken GW, Jenkins WM, Merzenich MM. 1996
Use-dependent alterations of movement representations in primary motor cortex of adult squirrel monkeys. Journal of Neuroscience 16: 785- 807. See Doidge N. 2007. The Brain That Changes Itself. New York: Viking/ Penguin.
Jueptner M, Stephan K, Frith CD, et al. 1997. Anatomy of motor learning. I. Frontal Ccrtex and attention to Action. Journal of Neurophysiology 77(3): 1313- 24. Johansen- Berg H, Matthews PM. 2002.
Attention to movement modulates activity in sensori- motor areas, including primary motor cortex. Experimental Brain Research 142(1): 13- 24. “Experience coupled with attention leads to physical changes in the structure and functioning of the nervous system”: Merzenich MM, deCharms RC. 1996.
“Neural representations, experience and change.” In Llinàs R, Churchland PS, eds. The Mind-Brain Continuum. Cambridge, MA: MIT Press.
A physiotherapist once told me ”the brain needs repetitions to form muscle memory.” Based on the above research that’s fairly inaccurate. There’s no doubt that when a child with CP is performing new functions and paying attention to how they are moving this is improving their brain mapping, so movement even rudimentary movement can be helpful. Some of what they are doing is effective when learning is actually occurring but some of what they are doing is introducing limitations. Mindless repetitions and the focus on muscles before brain is a limited approach and will produce limited outcomes, while new experiences and variations within the child’s present ability while they are paying attention and aware of the movement is helpful to create activity in the motor cortex.
Think of movement with attention as bringing about a virtual explosion of activity in the brain: Scans showed high levels of activity in the prefrontal cortex during new learning but not once the performance became routine.
I think of a martial artist, if they learned a block ineffectively and practiced it for years they would groove in the less than ideal movement. It’s so important when learning a new skill to go slow and do less repetitions until the ideal movement is formed. At that time repetitions are helpful to groove in the movement pattern in the brain. I think this is what’s commonly referred to as muscle memory. To use this technique before the ideal pattern is formed and learned as part of a rehabilitation strategy, is only going to introduce and groove in a limitation.
What is ideal movement? There is a trajectory of minimum effort, it is reversible and there is a perception of differences when done ideally compared to less than ideal movement.