Neuroplasticity refers to the nervous system's capacity to modify its connections, strength, and organization in response to experience, learning, injury, or environmental changes. It operates at multiple levels from synaptic to large-scale cortical remapping.
Types of Neuroplasticity
Structural plasticity involves physical changes such as synaptogenesis (new synapse formation), dendritic branching, and even adult neurogenesis in the hippocampus. Functional plasticity refers to the brain's ability to shift functions from damaged areas to intact regions. Synaptic plasticity - including long-term potentiation (LTP) and long-term depression (LTD) - is considered a cellular basis of learning.
Plasticity Across the Lifespan
While the brain is highly plastic during critical periods in early life, when neural circuits are shaped by experience, plasticity persists throughout adulthood. Learning a new skill, practicing a musical instrument, and recovering from stroke involve adult neuroplasticity. The rate and extent of plastic change decrease with age, but enriched environments, physical exercise, and cognitive challenges are thought to help maintain the brain's adaptive capacity.
Implications for Cognitive Training
The idea that cognitive training harnesses neuroplasticity to improve function underlies the brain-training industry. One account holds that repeated practice strengthens relevant neural circuits through Hebbian learning - neurons that fire together wire together. However, a review of brain-training intervention studies found extensive evidence of improvement on the trained tasks, less evidence of transfer to closely related tasks, and little evidence of transfer to distantly related tasks or to everyday cognitive performance.