How does Exercise Facilitate Neuroplasticity to Improve Motor Function Post-Stroke?

1. What is Neuroplasticity?

The term ‘neuro’ refers to the structure and functions of the brain, nerves, and their connections in the body. The term ‘plasticity’ infers the ability of a structure or an organism to be changed or shaped. ‘Neuroplasticity’ denotes the ability of the brain to functionally reorganise and form neural connections in response to the environment and new experiences. The ability of the brain to be able to change and form new connections, lays the foundation for learning new skills, movements, and the ability to recover following a brain injury (such as a stroke). 

2. How Does Exercise Promote Neuroplasticity? 

Exercise can be defined as a subset of physical activity that is planned, structured, repetitive, and purposeful. Aerobic exercise induces an increase in blood flow. This increase in blood flow stimulates the release of a protein called brain-derived neurotrophic factor (BDNF). Research suggests that BDNF plays an imperative role in the survival, maintenance, and growth of nerve cells. This protein nourishes nerve cells to optimise their function and stimulates the generation of new neurons (known as neurogenesis).

3. How Does Neuroplasticity Improve Motor Function Post-Stroke?

When the brain is injured (such as an injury that occurs from a stroke) nerve cells are damaged or altered causing dysfunction. Through exercise, and the subsequent release of BDNF, the potential there lies to create new neurological connections around an injury site (collateral sprouting and neurogenesis), or to promote the take-over from a healthy area of the brain (cortical reorganisation). Therefore, aerobic exercise has the potential to play an imperative role in stroke rehabilitation. Aerobic exercise prior to implementing activities with an affected limb, may elicit optimal BDNF production that ultimately facilitates neuroplasticity and the consequent enhancement of learning processes and acquisition of motor skills of the affected limb.  

Furthermore, optimal neuroplasticity requires sufficient repetition. The more a task is performed, the greater the centres of the brain become that are devoted to performing that movement. Through repeated, correct movement, the brain can be rewired- improving neuronal connections to facilitate biomechanically efficient movement and enhance quality of life. Motor skills or movement may be performed and/or re-learnt by volitional physical effort exerted by one’s-self (active movement), or involuntary motion produced by another person or machine. In addition, mirror therapy is used to improve motor function by creating an illusion that the affected limb is moving.