What is neuroplasticity?
noo͝r″ō-plăs-tĭs′ĭ-tē
You’ve probably heard this word before – especially in reference to performing “brain games” like crosswords or Sudoku to keep your mind sharp. In reality, neuroplasticity principles are steeped in research, and lay the foundation for some of the most evidence-based treatments we have for neurological conditions.
Let’s break the word down – “neuro”, meaning of the nervous system, including the brain and spinal cord, and “plasticity” – no, not Mean Girls cold, hard plastic! Plasticity here is kind of how plastics are referred to in the material science world – plastic is moldable, changeable; neuroplasticity then refers to our brain’s ability to change and adapt–but how does this occur?
Brain changes during learning
Let’s say you want to learn to type. At first, you might have to look for the keys, or maybe you’re typing one finger at a time. But with more practice, including learning where your fingers are supposed to go, and what keys each finger controls–you need to look down at your hands less, and your fingers start to “learn” where to go. By practicing over and over again, you tell the brain to light up the nervous system pathways needed to move your fingers, and in doing so, the nervous system devotes more resources to maintaining these pathways. This is part and parcel of Kleim’s classic principles of neuroplasticity, including the phrase “if you use it, you improve it”. Real, physiological changes start to occur in the brain – beefed up synaptic connections between nerves - as well as new connections between nerves - that transmit signals.
Cortical Reorganization
Interestingly, via new connections between neurons, our brain can unearth new pathways and change the function of our brain structure. Yeah. For example, the occipital lobe in our brain is responsible for processing visual information, among other things. In a process called cortical reorganization, individuals who have experienced visual impairment may have their occipital repurposed to beef up other senses, such as hearing, as an example.
It’s thought that these changes produce markers we can measure in the blood, including the “brain derived neurotrophic factor (BDNF)”, which is often used in research as a marker signaling increased neuroplasticity.
High intensity: the intersection of neuroplasticity and rehab!
Neuroplasticity is also at the heart of neurological rehab. For example, if an individual experiences profound weakness of their hand and arm function after a stroke, one of the most evidence-based strategies is called Constraint Induced Movement Therapy (CIMT), where the strong limb is actually constrained to force use of the affected arm and hand. Via beefing up old, and encouraging new connections between neurons, the brain tries to find a way to restore functioning of the limb.
Certain components enhance neuroplasticity, including intensity of practice. In recent research, individuals undergoing high intensity gait training can experience improvements in their walking function. As it turns out, those blood markers-including BDNF-increase in production when one practices with higher intensity! Want to know if you're exercising at a high intensity? Check out our practical guide!
References
Kleim JA, Jones TA. Principles of experience-dependent neural plasticity: implications for rehabilitation after brain damage. J Speech Lang Hear Res. 2008 Feb;51(1):S225-39. doi: 10.1044/1092-4388(2008/018). PMID: 18230848.
Corbetta D, Sirtori V, Castellini G, Moja L, Gatti R. Constraint-induced movement therapy for upper extremities in people with stroke. Cochrane Database Syst Rev. 2015;2015(10):CD004433. Published 2015 Oct 8. doi:10.1002/14651858.CD004433.pub3
Hornby TG, Reisman DS, Ward IG, et al. Clinical Practice Guideline to Improve Locomotor Function Following Chronic Stroke, Incomplete Spinal Cord Injury, and Brain Injury. J Neurol Phys Ther. 2020;44(1):49-100. doi:10.1097/NPT.0000000000000303