What does the word neuroplasticity actually mean?
Neuroplasticity is an umbrella term, commonly used to mean that the brain and nervous system is plastic (or malleable), and can be remodelled or ‘re-wired’ in response to experiences over a lifetime.
Your brain is made up of 100 billion or so neurons each making up to 10,000 connections, or synapses, with other neurons. Neurons communicate by sending chemical signals across the synapse, with neurotransmitter release determined by patterns of neural impulses.
Neural impulses code your thoughts, actions and experiences. But they’re not simply transmitted along hard-wired pathways in the brain; the same thoughts, actions and experiences continually reorganise the structure and function of pathways enabling your brain to respond efficiently and effectively to the world around you.
Because neuroplasticity research encompasses diverse fields including learning and memory, synaptic physiology, stem cell research, brain injury, psychotherapy, pharmacology, development and ageing, the way the term is used will differ depending on which neuroscientist you speak to, or whose book you read.
How do experiences rewire the brain?
Imagine you’ve started violin lessons. This intense learning experience requires a host of sensory, cognitive, and motor skills including reading music, translating it into sequential movements that in turn depend on auditory feedback, developing fine motor skills coupled with precise timing, memorising long musical passages, and so on. Research shows that musical training can result in neuroplasticity at many levels in the brain.
When you first pick up the violin, you’re clumsy and make many mistakes. But within a few days of focussed practice, neural circuits in the part of your brain devoted to fingering the strings for example, will begin to fire repeatedly. The more often neurons the specific circuit fire, the stronger the synaptic connections become. This is the basis of the adage ‘neurons that fire together, wire together’. Researchers have documented in detail the electrical, chemical and structural changes that take place at synapses to amplify connection strength during learning.
With continued daily violin practice, you’ll become more proficient. Neurons in the circuits involved in recognising musical tones, for example, will begin proliferating their dendrites (the branched extensions that receive inputs) and extending their axons, interconnecting more distant neurons into rich, well-organised neural networks. Accompanying these brain changes will be more nimble playing, less mistakes and more enjoyment!
Over the course of a many years, you may become a virtuoso. A study of your brain will reveal an enlarged cortical ‘map’ of the fingers of the hand that you’ve used for the complex task of fingering the strings, while your opposite hand, which has the less dexterity-demanding task of bowing the strings, does not show an altered map. An imaging study of your brain will show greater grey matter volume in the auditory region of your cortex. Psychological testing will reveal your spatial, verbal, and mathematical performance, and your general IQ will be higher than non-musicians. And as you age, your brain will be less susceptible to age-related degeneration.
Neuroplasticity over the course of life.
Training induced plasticity (such as violin lessons) is not restricted to childhood. But what differs as a function of age is the ease at which plasticity occurs. “During early childhood the plasticity switch is always ‘ON’, whereas in adults it’s usually ‘OFF’” explains Michael Merzenich, PhD, Emeritus Professor at the Keck Center for Integrative Neurosciences at the University of California.
Plasticity dials back ‘ON’ in adulthood when specific conditions that enable or trigger plasticity are met. “What recent research has shown is that under the right circumstances, the power of brain plasticity can help adults minds grow. Although certain brain machinery tends to decline with age, there are steps people can take to tap into plasticity and reinvigorate that machinery,” explains Merzenich. These circumstances include focused attention, determination, hard work and maintaining overall brain health.
Professor Tony Hannan, head of the Neural Plasticity group at the Florey Institute in Melbourne, agrees. “Discoveries in the field of neuroplasticity have implications for how each of us may protect our brain from the relentless weathering of ageing and disease. It’s known that lifestyle factors that are good for the body, such as regular physical exercise and a healthy diet, are also beneficial for the brain. And those who keep their brains stimulated with regular complex mental activities may also help delay onset of common brain diseases, such as Alzheimer’s and dementia”.
Neuroplasticity: can you rewire your brain? – ABC Active Memory: Brain Training News
Dr Sarah McKay is an Oxford-educated neuroscientist and science writer. She specialises in communicating neuroscience research in everyday language, and writes a brain and health blog.