Neuroplasticity

The tendency of neural networks in the brain to alter through development and reorganisation is known as neuroplasticity, also recognized as neural plasticity or brain plasticity. Individual neuron pathways creating new associations to systemic modifications including cortical remapping are examples of these shifts.

Circuit and network shifts as a consequence of learning a new skill, environmental stimuli, practise, and psychological stress are examples of neuroplasticity.

Neuroplasticity of the brain has been believed to be limited to infancy, but studies in the latter half of the twentieth century revealed that many facets of the brain can be changed even in adulthood. The developing brain, on the other hand, is more plasticity psychology than that of the adult brain. Activity-dependent plasticity has important consequences for healthy growth, memory, learning, and brain injury repair.

Types of Neuroplasticity

In their book "Toward a Theory of Neuroplasticity," Christopher Shaw and Jill McEachern (eds) argue that there is no all-encompassing theory that encompasses various frameworks and processes in the research of neuroplasticity. Neuroplasticity of the brain, on the other hand, is often described by researchers as "the capacity to make adaptive changes based on the structure and function of the nervous system." Structural neuroplasticity and functional neuroplasticity are the two forms of neuroplasticity that are frequently addressed.

Structural Neuroplasticity

The capacity of the brain's neuronal connections to alter is sometimes referred to as structural plasticity. Depending on this form of neuroplasticity, new neurons are continuously developed and introduced into the central nervous system during one's life. To understand the structural changes of the human brain, researchers have used a variety of cross-sectional imaging methods (e.g., computerised tomography (CT), magnetic resonance imaging (MRI)). The influence of different internal or external stimuli on the brain's anatomical reorganisation is also studied in this form of neuroplasticity. 

Changes throughout the proportion of grey matter or synaptic strength in the brain are examples of intrinsic neuroplasticity. In today's academia, structural neuroplasticity is being studied further in the area of neuroscience.

Functional Neuroplasticity

The capacity of the brain to change and adjust the functional properties of neurons is referred to as functional plasticity. Alterations may occur as a result of prior action (activity-dependent plasticity) to help people remember things, or as a result of a failure or damage to neurons (reactive plasticity) to compensate for a pathological event.

Through the latter case, functions of one area of the brain are transferred to yet another part of the brain in response to a requirement for behavioural or physiological processes to be recovered. Synaptic plasticity refers to the physiological aspects of activity-dependent plasticity that include synapses.

Long-term potentiation (LTP) and long-term depression (LTD) are two types of synaptic plasticity that are linked to memory. These include the weakening or strengthening of synapses, which leads to an increase or reduction in the rate of fire of neurons.

Applications and Examples

The adult brain does not have any of its neuronal pathways "hard-wired." Multiple examples of cortical and subcortical rewiring of neuronal circuits in reaction to training and injury have been reported. Neurogenesis (the birth of new brain cells) has been shown to happen in the adult human brain, and these changes will last far into old age.

The hippocampus and olfactory bulb have been implicated in neurogenesis, however recent research has shown that certain brain regions, including the cerebellum, may also be involved. Nevertheless, the extent of rewiring caused by the insertion of new neurons into existing circuits is unknown, and these rewiring could be functionally redundant.

Treatment of Brain Damage

The brain activity relation to a given role may be moved to a different location as a result of neuroplasticity; it might happen in the case of normal experience or during the healing phase after a brain injury.

The theoretical rationale for treating acquired brain injury through goal-directed experiential therapeutic programmes in the form of recovery approaches to the functional effects of the injury is based on neuroplasticity.

Binocular Vision: For decades, scientists believed that humans would have to develop binocular vision, specifically stereopsis, in young life or else they would never develop it.

Effective advances in people with amblyopia, convergence insufficiency, as well as other stereopsis anomalies are becoming good examples of neuroplasticity in recent times; binocular vision improvements and stereopsis recovery have become active fields of science and clinical study.

Phantom Limbs: Phantom limb sensation is a condition in which a person appears to experience pain or sensation in a  body part which has been amputated. This is unusually normal, with 60–80 percent of amputees experiencing it. The cortical maps of the withdrawn limbs are thought to have been associated with the region over them in the postcentral gyrus, which is explained by the principle of neuroplasticity.

As a consequence, activity in the region of the cortex covering the amputated limb is misunderstood by the region of the cortex liable for the amputated limb.

Chronic Pain: Chronic pain affects people who have formerly been injured but are now well. This is linked to neuroplasticity, which occurs as a result of a maladaptive reorganisation of the nervous system, including peripherally and centrally.

Nociceptive feedback from the periphery to the CNS (central nervous system) is increased during the time of tissue damage due to noxious stimuli and inflammation. Long-term peripheral nociception triggers a neuroplastic reaction at the cortical level, causing the somatotopic organisation of the painful site to shift, resulting in central sensitization.

Meditation: Meditation practise has been related to variations in cortical thickness or grey matter density in a variety of studies. Sara Lazar of Harvard University conducted one of the most well-known research that shows the same in 2000. Richard Davidson, a neuroscientist at the University of Wisconsin, has conducted research on the impact of meditation upon the brain in conjunction with the Dalai Lama.

His findings indicate which long-term or short-term meditation practices may lead to varying levels of activity in brain regions linked to effects including concentration, neuroplasticity and depression, anxiety, frustration, fear, and compassion, as well as the body's ability to recover itself. Changes in physical structure of the brain may have been causing such functional changes.

Fitness and Exercise: Adult neurogenesis is aided by aerobic exercise, which increases the development of neurotrophic factors including vascular endothelial growth factor (VEGF), brain-derived neurotrophic factor (BDNF), and insulin-like growth factor 1 (IGF-1). Exercise-induced hippocampus neurogenesis is linked to measurable changes in spatial memory. Over the course of a few months, regular aerobic exercise results in clinically relevant changes in executive function (that is, "cognitive control") and increased grey matter volume throughout multiple brain regions, especially those which give way to cognitive control and therefore leading to neuroplasticity healing.

Deafness and loss of hearing: Hearing loss causes compensatory plasticity throughout the auditory cortex as well as other association parts of the brain in deaf and hard of hearing individuals. Hearing people's auditory cortex, which is normally reserved for processing auditory information, has now been diverted to fulfill certain functions, particularly vision and somatosensation.

Blindness: Blind people's visual cortex can experience cross-modal plasticity as a result of vision loss, resulting in greater skills in several other senses. Alternatively, the absence of visual feedback may stifle the production of many other sensory systems.