Neuroplasticity
Also known as: brain plasticity, synaptic plasticity, experience-dependent plasticity
The brain's capacity to change its structure and function in response to experience, learning, injury, or environmental demands — present throughout the lifespan, though it shifts in character with age.
Neuroplasticity is the umbrella term for the brain's ability to reorganise itself — structurally and functionally — in response to experience, learning, or injury. It is the biological basis for memory, skill acquisition, recovery after brain injury, and the accumulation of cognitive reserve.
Plasticity is sometimes described as if it is exclusively a feature of young brains. In reality, it persists throughout life — but its mechanisms, speed, and degree of expression shift considerably across the lifespan.
Forms of neuroplasticity
| Form | Scale | Timescale |
|---|---|---|
| Synaptic potentiation / depression (LTP / LTD) | Single synapse | Milliseconds to hours |
| Structural synaptic remodelling | Dendritic spines, axon boutons | Hours to days |
| Cortical map reorganisation | Regions, networks | Days to months |
| Neurogenesis | New neurons | Weeks (mainly hippocampal dentate gyrus) |
| White matter remodelling | Tract myelination | Weeks to years |
Plasticity in ageing
As the brain ages, several features of plasticity change:
- Reduced rate and magnitude — synaptic potentiation occurs less readily in older tissue, partly due to changes in NMDA receptor expression
- Greater reliance on compensatory recruitment — older adults performing the same cognitive task as young adults often activate a broader network of regions (a phenomenon called HAROLD — Hemispheric Asymmetry Reduction in Older Adults)
- Maintained functional plasticity — despite structural changes, the aged brain retains meaningful capacity for skill learning and adaptation, particularly with sustained practice
Why it matters for brain age
Plasticity is one of the mechanisms through which lifestyle factors — aerobic exercise, cognitive engagement, social interaction — may slow brain ageing. Exercise, for example, upregulates brain-derived neurotrophic factor (BDNF), which supports synaptic plasticity and hippocampal neurogenesis. These effects are reflected, over years, in slower accumulation of structural changes and smaller brain age gaps.
Plasticity after injury
After stroke or other focal brain injury, plasticity drives recovery. Perilesional tissue and homologous regions in the opposite hemisphere can partially take over lost functions — the basis for neurorehabilitation. However, this same plasticity can sometimes be maladaptive, entrenching compensatory strategies that limit optimal long-term recovery.
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Related terms
Cognitive reserve
The brain's accumulated resilience against pathology — built over a lifetime through education, cognitive engagement, and social activity — which allows some people to sustain function despite significant structural brain changes.
Atrophy
The loss of brain tissue volume or cortical thickness over time, reflecting a reduction in the size or number of neurons and their supporting cells.
Default mode network
A set of brain regions that are most active when the mind is at rest and not focused on an external task — linked to self-referential thinking, memory retrieval, and mind-wandering.
Brain age gap
The difference between brain age and chronological age. A positive gap means the brain looks older than it should; a negative gap, younger.