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- nervous system
- Brain
- cross-modal plasticity
- neuron
neuroplasticity
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What is neuroplasticity?
Neuroplasticity is the capacity of the brain's neurons and neural networks to change their connections and behavior in response to various stimuli, including new information, sensory stimulation, development, damage, or dysfunction.
Developmental plasticity occurs in the young brain when neurons rapidly form connections. As the brain processes sensory input, some synapses strengthen while others weaken, and unused synapses are eliminated through synaptic pruning, resulting in efficient neural networks. Throughout life, these neural connections are fine-tuned through interactions with the environment.
Neuroplasticity allows the brain to compensate for changes in the body, reinforce sensory information through learning and memory, and recover from physical damage. The brain adjusts the strength or number of synapses between neurons, which can lead to positive or negative reorganization. Techniques and interfaces can harness neuroplasticity for therapeutic purposes, and neurogenesis may play a role in recovery from conditions like stroke.
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How does neuroplasticity affect the brain?
Neuroplasticity is the ability of the brain's neurons and neural networks to change their connections and behavior in response to various stimuli, including new information, sensory stimulation, development, damage, or dysfunction.
Neuroplasticity can manifest in different forms, such as developmental plasticity, which involves rapid growth and synapse formation in the young brain. Synaptic pruning eliminates unused synapses, leaving efficient neural connections. The aging brain also demonstrates neuroplasticity by forming new synapses to compensate for neuronal loss. Additionally, when the initial strategy cannot be followed due to impairment, the brain figures out an alternative strategy for carrying out a task.
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What factors can change or influence neuroplasticity?
Neuroplasticity, the brain's ability to change and reorganize itself, is influenced by various factors, including new information, sensory stimulation, development, damage, or dysfunction.
During development, the young brain rapidly forms synapses, strengthening some and weakening others based on sensory input. Unused synapses are eliminated through synaptic pruning. Throughout life, interaction with the environment fine-tunes these neural connections.
Other factors include:
* Map expansion Repeated behavior or stimuli can cause the region of the cortical map dedicated to that function to grow.
* Aging Aging entails both degeneration and neuroplasticity. While neurons atrophy and die, the aging brain also forms new synapses to compensate for neuronal loss.
* Environmental stimuli Nutrition, sensory experience, social interaction, and learning are essential for the proper differentiation of individual neurons and for fine-tuning the details of synaptic connections.4 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
How does learning a new skill use neuroplasticity?
Neuroplasticity is the capacity of the brain to change its connections and behavior in response to new information, sensory stimulation, damage, or dysfunction. When learning a new skill, the brain uses neuroplasticity to reorganize itself by forming new neural connections and strengthening existing ones.
Repeated behavior or stimuli can cause the region of the cortical map dedicated to that function to grow. This process occurs when learning and practicing a skill, like playing a musical instrument. The region grows as familiarity with the skill increases and shrinks back to baseline once the learning becomes explicit. With continued practice, the region retains the initial enlargement.
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Can neuroplasticity help people recover from brain injuries? How?
Yes, neuroplasticity can help people recover from brain injuries. Neuroplasticity refers to the brain's ability to change and reorganize its connections and functions in response to various stimuli, including damage.
After a brain injury, the brain can employ neuroplasticity to compensate for lost functions. This can occur through several mechanisms, such as compensatory masquerade, where the brain figures out alternative strategies to carry out tasks when the initial strategy is impaired, or by encouraging intact nerve cells to grow new branches or increase their activity to replace lost or damaged neurons. In some instances, brain-computer interfaces and techniques like real-time visual feedback from functional magnetic resonance imaging (fMRI) can enable patients to retrain their brains and improve brain functioning.
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How do scientists study neuroplasticity in humans and animals?
Scientists employ various methods to study neuroplasticity in humans and animals, using techniques like:
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Transcranial Magnetic Stimulation (TMS) TMS is a noninvasive technique that stimulates neurons in the brain cortex using electromagnetic induction. It helps in understanding how the body and sensory experiences are organized in the brain.
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Brain-computer interfaces Neuroscientists are developing machines that interface directly with the brain, bypassing external sense organs. Real-time visual feedback from functional magnetic resonance imaging (fMRI) can enable patients to retrain their brains and improve brain functioning.
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Brain imaging Functional magnetic resonance imaging (fMRI) is used to measure the magnetic fields created by nerve cells in the brain, detecting changes in blood flow. This information can be translated into images, which virtually light up the amount of activity in different areas of the brain as the person performs mental tasks.
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News •
neuroplasticity, capacity of neurons and neural networks in the brain to change their connections and behaviour in response to new information, sensory stimulation, development, damage, or dysfunction. Although some neural functions appear to be hard-wired in specific, localized regions of the brain, certain neural networks exhibit modularity and carry out specific functions while also retaining the capacity to deviate from their usual functions and to reorganize themselves. Hence, neuroplasticity is considered generally to be a complex, multifaceted, fundamental property of the brain. (For more information about the anatomy and functions of the brain and nervous system, see the article human nervous system.)
Rapid change or reorganization of the brainās cellular or neural networks can take place in many different forms and under many different circumstances. Developmental plasticity occurs when neurons in the young brain rapidly sprout branches and form synapses. Then, as the brain begins to process sensory information, some of these synapses strengthen and others weaken. Eventually, some unused synapses are eliminated completely, a process known as synaptic pruning, which leaves behind efficient networks of neural connections. Other forms of neuroplasticity operate by much the same mechanism but under different circumstances and sometimes only to a limited extent. These circumstances include changes in the body, such as the loss of a limb or sense organ, that subsequently alter the balance of sensory activity received by the brain. In addition, neuroplasticity is employed by the brain during the reinforcement of sensory information through experience, such as in learning and memory, and following actual physical damage to the brain (e.g., caused by stroke), when the brain attempts to compensate for lost activity.
The same brain mechanismsāadjustments in the strength or the number of synapses between neuronsāoperate in all these situations. Sometimes this happens naturally, which can result in positive or negative reorganization, but other times behavioral techniques or brain-machine interfaces can be used to harness the power of neuroplasticity for therapeutic purposes. In some cases, such as stroke recovery, natural adult neurogenesis can also play a role. As a result, neurogenesis has spurred an interest in stem cell research, which could lead to an enhancement of neurogenesis in adults who suffer from stroke, Alzheimer disease, Parkinson disease, or depression. Research suggests that Alzheimer disease in particular is associated with a marked decline in neurogenesis.
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Types of cortical neuroplasticity
Developmental plasticity occurs most profoundly in the first few years of life as neurons grow very rapidly and send out multiple branches, ultimately forming too many connections. In fact, at birth, each neuron in the cerebral cortex (the highly convoluted outer layer of the cerebrum) has about 2,500 synapses. By the time an infant is two or three years old, the number of synapses is approximately 15,000 per neuron. This amount is about twice that of the average adult brain. The connections that are not reinforced by sensory stimulation eventually weaken, and the connections that are reinforced become stronger. Eventually, efficient pathways of neural connections are carved out. Throughout the life of a human or other mammal, these neural connections are fine-tuned through the organismās interaction with its surroundings. During early childhood, which is known as a critical period of development, the nervous system must receive certain sensory inputs in order to develop properly. Once such a critical period ends, there is a precipitous drop in the number of connections that are maintained, and the ones that do remain are the ones that have been strengthened by the appropriate sensory experiences. This massive āpruning backā of excess synapses often occurs during adolescence.
American neuroscientist Jordan Grafman has identified four other types of neuroplasticity, known as homologous area adaptation, compensatory masquerade, cross-modal reassignment, and map expansion.
Homologous area adaptation
Homologous area adaptation occurs during the early critical period of development. If a particular brain module becomes damaged in early life, its normal operations have the ability to shift to brain areas that do not include the affected module. The function is often shifted to a module in the matching, or homologous, area of the opposite brain hemisphere. The downside to this form of neuroplasticity is that it may come at costs to functions that are normally stored in the module but now have to make room for the new functions. An example of this is when the right parietal lobe (the parietal lobe forms the middle region of the cerebral hemispheres) becomes damaged early in life and the left parietal lobe takes over visuospatial functions at the cost of impaired arithmetical functions, which the left parietal lobe usually carries out exclusively. Timing is also a factor in this process, since a child learns how to navigate physical space before he or she learns arithmetic.
Compensatory masquerade
The second type of neuroplasticity, compensatory masquerade, can simply be described as the brain figuring out an alternative strategy for carrying out a task when the initial strategy cannot be followed due to impairment. One example is when a person attempts to navigate from one location to another. Most people, to a greater or lesser extent, have an intuitive sense of direction and distance that they employ for navigation. However, a person who suffers some form of brain trauma and impaired spatial sense will resort to another strategy for spatial navigation, such as memorizing landmarks. The only change that occurs in the brain is a reorganization of preexisting neuronal networks.
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