Psychology
Neuroplasticity and Recovery After Brain Injury
Quick fact
A single neuron can grow up to 10,000 new connections after injury, and the brain can 'rewire' entire functional regions—for example, areas that controlled a hand can take over processing touch from an arm.
Why this is interesting
You've likely heard that 'you can't grow new brain cells,' yet many people recover speech, movement, and memory after a serious stroke or head injury. How does the brain actually fix itself?
Read the full explanation
Understanding Neuroplasticity and Recovery After Brain Injury
Imagine a city where a major bridge collapses. Traffic doesn't stop entirely—drivers find new routes through side streets, build temporary bridges, and eventually the network adapts. That's what neuroplasticity does after brain injury. When neurons die or pathways are severed, the brain doesn't just give up. It gradually reorganises by: (1) surviving neurons sending out new branches (sprouts) to connect with undamaged partners, (2) strengthening nearby existing synapses to take on more workload, and (3) recruiting distant brain regions to perform lost functions. This process is most active in the weeks and months after injury, but can continue for years with the right stimulation.
A deeper explanation
Mechanistically, neuroplasticity after injury relies on several cellular and molecular events. Axonal sprouting is guided by growth-associated proteins (e.g., GAP-43) and stopped by inhibitory molecules like Nogo-A. Synaptic strengthening uses long-term potentiation (LTP) mechanisms that increase receptor density and neurotransmitter release. Cortical remapping involves shifts in representational maps—for example, hand motor cortex areas may shrink if unused, while adjacent areas expand. Rehabilitation works by driving use-dependent plasticity: repetitive, task-specific practice triggers Hebbian learning ('cells that fire together, wire together'), encouraging the formation of stable new circuits. The brain's ability to compensate is limited by the size and location of injury, age, and the availability of supportive factors like neurotrophins (BDNF). Understanding these principles has led to therapies like constraint-induced movement therapy and transcranial magnetic stimulation, which harness neuroplasticity to maximise recovery.