Neural plasticity (neuroplasticity) refers to the brain's ability to change its structure and function in response to experience, learning, development, and injury. It operates at multiple levels: synaptic plasticity (strengthening or weakening of individual connections), structural plasticity (growth of new synapses and dendrites), and large-scale reorganization (remapping of cortical representations). Plasticity is the biological basis of all learning and memory and enables partial recovery from brain damage.
Key Structures
- Distributed (cortical remapping)
- Hippocampus (neurogenesis) — A medial temporal lobe structure essential for the formation of new declarative memories and spatial navigation — one of the most studied structures in cognitive neuroscience.
- Motor cortex (skill learning) — The precentral cortical region that plans, initiates, and executes voluntary movements through corticospinal projections, particularly in relation to skill learning.
- Somatosensory cortex (experience-dependent changes)
- Dendrites — The branching extensions of a neuron that receive electrochemical signals from other neurons and conduct them toward the cell body for integration.
Key Functions
The brain's ability to reorganize its structure and function in response to experience, learning, injury, or environmental demands, through mechanisms including synaptogenesis, synaptic pruning, neurogenesis, and cortical remapping.
Forms of Plasticity
Experience-dependent plasticity reflects the brain's response to environmental input: musicians develop enlarged cortical representations for their practiced hand, London taxi drivers have larger hippocampi, and learning to juggle produces detectable gray matter changes within weeks. Experience-expectant plasticity occurs during critical periods when the brain requires specific input for normal development (e.g., visual input for visual cortex development). Compensatory plasticity enables recovery after brain damage by recruiting alternative neural pathways.
Plasticity is greatest during critical (or sensitive) periods in development — windows when the brain is especially responsive to environmental input. After critical periods close, plasticity is reduced but not eliminated. Recent research has identified molecular mechanisms that regulate critical period opening and closing (including perineuronal nets and specific neurotransmitter systems), raising the possibility of reopening critical periods to enable adult learning or recovery with the plasticity of the developing brain.
Disorders
- Stroke recovery (post-injury plasticity)
- Phantom limb pain (maladaptive plasticity) — Vivid perception of pain or sensation in a limb that has been amputated; caused by cortical reorganization and maladaptive plasticity.
- Chronic pain — Persistent pain lasting beyond normal tissue healing, involving central sensitization and neuroplastic changes in pain processing circuits.
- Learning disabilities — Neurodevelopmental conditions affecting the acquisition of reading, writing, or mathematical skills despite adequate intelligence and instruction.
- Amblyopia — Reduced vision in one eye due to abnormal visual development in childhood; brain favors the other eye.