Neuroplasticity - The Brain’s Ability to Rewire Itself
Neuroplasticity refers to the brain’s ability to reorganize itself by forming new neural connections throughout life. Neuroplasticity allows the neurons (nerve cells) in the brain to compensate for injury and disease and to adjust their activities in response to new situations or to changes in their environment.
Brain reorganization takes place by mechanisms such as “axonal sprouting” in which undamaged axons grow new nerve endings to reconnect neurons whose links were injured or severed. Undamaged axons can also sprout nerve endings and connect with other undamaged nerve cells, forming new neural pathways to accomplish a needed function.
For example, if one hemisphere of the brain is damaged, the intact hemisphere may take over some of its functions. The brain compensates for damage in effect by reorganizing and forming new connections between intact neurons. In order to reconnect, the neurons need to be stimulated through activity.
Neuroplasticity and Stroke
One significant area of application for neuroplasticity is in stroke recovery. Rehabilitation involving neuroplasticity principles requires repetition of task and task specific practice to be effective. What this means for the stroke patient is that going to see your therapist for a one hour visit (or even a 3 hour visit) is not enough to lead to neuroplastic changes in the brain. Patients need to think of physical, occupational, and speech therapy as an adjunct to stroke recovery. It’s up to the patient to make the most of recovery by continuously using the injured parts of the body and mind outside of therapy sessions in everyday life.
Neuroscientist Dr. Edward Taub has created one of the most technologically advanced methods for treating people that have had strokes or other neurological disorders that cause severe physical impairments or paralysis. His method, termed constraint-induced (CI) movement therapy, is a therapeutic approach to the rehabilitation of movement after stroke, multiple sclerosis (MS), and traumatic brain injury (TBI). In simple words, CI therapy consists of a family of treatments that teach the brain to “rewire” itself following an injury to the brain, the foundation of which is based upon neuroplasticity.
Constraint induced therapy involves limiting the movement of the non-affected or stronger arm and instead using the affected or weaker arm more frequently and intensely. There has been some positive research results with constraint induced therapy, however, it requires effort and patience from the stroke patient. Some other treatments that may help with brain reorganization include interactive metronome, brain retraining software and websites, mirror box therapy, and robotic and gait devices that assist with movement repetition.
Hope for Improved Stroke Recovery Strategies in the Future
Rehabilitation strategies that promote motor learning-related neuroplasticity hold promise for improving functional outcomes following a stroke. Aerobic exercise may be a particularly effective means of enhancing the capacity of the motor system for plasticity by upregulation of neurotrophins, such as BDNF. Importantly, aerobic exercise alone does not induce neuroplasticity but rather promotes the development of a neural environment that is supportive of plasticity. To capitalize on this effect for motor rehabilitation, rounds of aerobic exercise may need to be performed in close timing with purposeful motor skill practice.
Genetics may also have a role to play. The basic neuronal processes that govern the effects of aerobic exercise on the brain and facilitate motor learning–related neuroplasticity, depend on the expression of specific genes that produce BDNF. Knowledge of these genetic variants could be used to better individualize motor rehabilitation strategies. As personalized health care becomes more refined, the effects of rehabilitation may be improved by incorporating genetic information. Future research into aerobic exercise and genetics may provide exciting new directions for the development of rehabilitation strategies designed to promote neuroplasticity and improve motor recovery after stroke.