By Marzia Khan
Reviewed by Danielle Ellis, B.Sc.
Understanding neuroplasticity
Neuroplasticity, or brain plasticity, can be defined as the ability of the nervous system to alter its activity in response to a stimulus by reorganizing its structure, function, and neuronal connections.
The history of plasticity can be traced to William James in 1890, with the first mention of the word ‘plasticity’ being reported in connection with the nervous system. However, the phrase ‘neural plasticity’ has been credited to Jerzy Konorski in 1948, while being made popular by Donald Hebb in 1949.
Adaptive structural and functional changes to the brain can occur after injuries, including a traumatic brain injury or a stroke, which can be beneficial to restoring functionality. However, it can also cause neural changes that lead to no beneficial changes or cause negative impacts and have pathological consequences.
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Structural plasticity can be described as the ability of neurons to change their physical structure due to learning, which alters gray matter volume or proportion in the brain. These types of structural changes also occur during development and growth, with neurons traveling from their origin to their final position within the brain.
Functional plasticity, on the other hand, can be defined as the ability of the brain to adapt or alter the physiological properties of neurons.
Interestingly, the hippocampus region of the brain demonstrates brain plasticity, including both structural and functional plasticity into adulthood.
The brain’s ability to change
Neuroplasticity is a vital process for both learning and memory, as uncovered by researchers building their knowledge on understanding the biological basis of these concepts.
Research into synaptic transmission has provided enhanced comprehension of cellular and molecular changes that occur during learning and memory, which have been found to be responsible for behavioral changes.
Donald Hebb proposed that learning was mediated by alterations in synaptic strength or efficacy, as when an animal learned something new, some synapses became stronger. He theorized that this consisted of particular synapses in a neuronal pathway that was responsible for learned behavior, providing a large postsynaptic response to the presynaptic neuron being stimulated. This theory was eventually concluded as being correct.
There is also accumulating evidence for the functionality of other regions of the brain, predominantly areas related to motor function, that also mediate learning and memory of motor function and skills. The hippocampus is reported to be involved in forming declarative memory, such as memory of faces, words, or facts. In contrast, the cerebellum and basal ganglia are involved in forming procedural memories, including learning tasks such as driving a car or playing an instrument.
Interestingly, damage to the hippocampus can lead to an individual that can learn new procedures, such as learning how to drive a car, but not declarative memory, preventing them from remembering the rules for driving a car.
Neuroplasticity and brain health
Synaptic plasticity has a significant role in maintaining neuronal connections and leads to changes in the structure of synapses and dendritic spines, as well as synaptogenesis and axonal alterations.
When contact is disturbed between neurons, this can lead to senile changes and diseases that impact the elderly, such as dementia, which can be caused by diseases such as Alzheimer’s disease, Parkinson’s disease, and others. These diseases can be characterized by cognitive dysfunction, personality and emotional modifications, and psychopathological disorders.
Neuroplasticity reconstructs brain function and repairs developmental disorders; however, the repair of brain damage is dependent on the level of central lesions. This is a significant consideration for neurorehabilitation treatment for patients with central nervous system disorders such as Alzheimer’s disease.
Recent studies have suggested that physical exercise programs that are intensive and cognitively demanding can induce changes in brain plasticity in Parkinson’s disease. A study has also expanded on this concept, with physical training protecting dopaminergic neurons produced by neurotoxins in rodent parkinsonism models.
Neurogenesis and synaptic plasticity decrease with age, which contributes to the development and progression of neurodegenerative processes; this impairs the brain’s ability to compensate for the impact of physiological aging or any occurring damage while maintaining normal functionality.
Preventing and slowing cognitive decline and maintaining cognitive function in older adults can be promoted by engaging in activities that increase neuroplasticity through learning new skills or being active via exercise.
The ability of the brain to cope with damage, known as the cognitive reserve, significantly reduces the risk of dementia and other age-related neurodegenerative diseases.
Harnessing neuroplasticity
With the decline in neuroplasticity being associated with aging and increasing the risk of neurodegenerative disease development, improving neuroplasticity through strategies such as physical exercise, cognitive stimulation, social engagement, dietary interventions, caloric restriction, and sleep hygiene can prevent the progress of neurodegeneration in an aging brain.
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Diet and nutrition have a significant role in increasing neuroplasticity, especially during the aging process, due to the brain requiring a high amount of nutrients, including vitamins, minerals, essential fatty acids, and antioxidants. Many studies have found that a healthy and rich diet with fruits, vegetables, whole grains, and lean proteins provides necessary nutrients that enable good brain health and functionality.
Additionally, sleep is also critical in maintaining brain health and cognitive function, especially in older adults who are recommended to sleep for 7-8 hours per night. Many studies have shown the significance of sleep in increasing neuroplasticity; this is because sleep is critical for cleansing toxic waste products and enabling brain regeneration.
Brain training through virtual reality, transcranial magnetic stimulation, and constraint-induced movement therapy can also be used to increase neuroplasticity as they focus on brain circuits, which promote synaptic plasticity and improve cognitive capacity.
Overall, increasing neuroplasticity can maintain cognitive function and work to reduce and prevent the risk of neurodegenerative diseases.
References
Puderbaugh M, Emmady PD. Neuroplasticity. National Library of Medicine. Published May 1, 2023. https://www.ncbi.nlm.nih.gov/books/NBK557811/
Joshua AM. Neuroplasticity. Physiotherapy for Adult Neurological Conditions. Published online 2022:1-30. doi:https://doi.org/10.1007/978-981-19-0209-3_1
Dorszewska J, Kozubski W, Waleszczyk W, Zabel M, Ong K. Neuroplasticity in the Pathology of Neurodegenerative Diseases. Neural Plasticity. 2020;2020:1-2. doi:https://doi.org/10.1155/2020/4245821
Marzola P, Melzer T, Pavesi E, Gil-Mohapel J, Brocardo PS. Exploring the Role of Neuroplasticity in Development, Aging, and Neurodegeneration. Brain Sciences. 2023;13(12):1610. doi:https://doi.org/10.3390/brainsci13121610
Kumar J, Patel T, Sugandh F, et al. Innovative approaches and therapies to enhance neuroplasticity and promote recovery in patients with neurological disorders: A narrative review. Cureus. 2023;15(7). doi:https://doi.org/10.7759/cureus.41914
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