Neuroplasticity

What is Neuroplasticity?

Neuroplasticity, also called brain plasticity or neural plasticity, is the brain's capacity to change in response to experience, its environment, and injury. This adaptability includes changes in neural connections and their strength. Neurogenesis is a distinct process that can contribute in some settings; it is not required for every form of plasticity. Neuroplasticity is essential for learning, memory, and recovery from brain injuries.

Key Features

• Synaptic Plasticity

  Synaptic plasticity is the ability of synapses, the connections between neurons, to change their strength in response to different patterns of neural activity. This process is vital for learning and memory, as it allows the brain to encode new information by adjusting the strength of synaptic connections.

• Neurogenesis

  Neurogenesis is the process by which new neurons are generated from neural stem cells. Neurogenesis is most active during development. Adult neurogenesis is well established in several animal models, but its extent and roles vary across species. Human hippocampal evidence is growing. Neurogenesis contributes to neuroplasticity by providing a source of new neurons that can integrate into existing neural circuits.

• Experience-dependent Plasticity

  Experience-dependent plasticity refers to changes in the nervous system that occur in response to specific experiences or environmental stimuli. These changes help the brain adapt to experience; plasticity does not mean every change is beneficial.

Applications

• Learning and Memory

  Neuroplasticity is a fundamental mechanism underlying learning and memory. Changes in synaptic strength and circuit organization support the encoding and storage of information; this does not mean that each new memory requires new neurons.

• Brain Injury Recovery

  Following brain injury, such as a stroke or traumatic brain injury, neuroplasticity can play a crucial role in recovery. Reorganization can support partial compensation after injury, but recovery depends on the injury, remaining pathways, rehabilitation, and other factors. Other regions do not necessarily replace all functions of damaged tissue.

• Neurorehabilitation

  Neurorehabilitation techniques, such as physical therapy, occupational therapy, and speech therapy, often rely on the principles of neuroplasticity to promote recovery after brain injury. These therapies aim to stimulate and enhance the brain's ability to reorganize itself and adapt to new challenges.

An example of neuroplasticity

Learning a new movement sequence illustrates why experience-dependent change matters: practice can change how the involved circuits function. Improvement in performance alone does not show which synapses changed or prove that new neurons formed.

Factors Influencing Neuroplasticity

Various factors can influence the extent and nature of neuroplasticity in the nervous system, including age, genetics, and environmental factors. In general, neuroplasticity tends to be more robust during early development, when the brain is rapidly forming new connections and refining its neural circuits. However, neuroplasticity persists throughout life, albeit at a reduced capacity, allowing the adult brain to adapt and change in response to new experiences and challenges.

Sources and further reading

Kleim and Jones on plasticity and rehabilitation; Disouky and colleagues on adult human hippocampal neurogenesis.