THE SCIENCE


What is neuroplasticity?

Neuroplasticity describes lasting change to the central nervous system (brain, retina, optic nerve, spinal cord) throughout a human’s life, supported by research that showed many aspects of the brain remain changeable (or “plastic”) even into adulthood.1,2 The nervous system reorganizes its structure, function and connections as a response to intrinsic and extrinsic stimuli.3 The changes occur at all levels: from the molecular to cellular to system to behavior and can occur during development, in response to environment, in support of learning, in response to disease or in relation to therapy.3

Neuroplasticity is possible because the adult brain is not entirely “hard-wired” with fixed neuronal circuits. There are many instances of rewiring of neuronal circuits in response to training. There is evidence that neurogenesis (birth of brain cells) occurs in the adult brain—and such changes can persist well into old age.2

Research has demonstrated that the adult brain can increase in volume (Colcombe et al., 2006; Pajonk et al., 2010), new neurons (neurogenesis) and new blood vessels (angiogenesis) can be formed, production of neurotrophic factors (molecules involved in neurogenesis, neuroprotection and synaptic plasticity) can be increased (Cotman and Berchtold, 2002; Gomez-Pinilla et al, 2002; Farmer et al., 2004; Kramer and Erickson, 2007; Rhyu et al., 2010), and the brain network functioning can be enhanced (Colecombe et al., 2004) all as a function of physical training and aerobic exercise. Optimal recovery is achieved through repetitive practice with appropriate feedback of functionally relevant tasks at the right time (Speech Lang Hear Res 51:5225, 2008). The key principles of experience-dependent neural plasticity that result in such recovery are: 1. use it and improve it; 2. specificity; 3. repetition matters; 4. intensity matters; 5. time matters.

Relationship between neurological deficits, neuroplasticity, therapeutic interventions and assessment of function:

1. Livingston, R.B. (1966) Brain mechanisms in conditioning and learning. Neurosciences Research Program Bulletin 4(3):349-354.
2. Rakic, P. (January 2002). “Neurogenesis in adult primate neocortex: an evaluation of the evidence”. Nature Reviews Neuroscience 3 (1): 65–71.cual-Leone A., Amedi A., Fregni F., Merabet L. B. (2005). “The plastic human brain cortex”. Annual Review of Neuroscience 28: 377–401.
3. Cramer S.C., Sur M., Dobkin B., O’Brien C; et al. (2011) “Harnessing neuroplasticity for clinical applications”. Brain 134: 1591-1609.