Neuroplasticity
[2] Examples of neuroplasticity include circuit and network changes that result from learning a new ability, information acquisition,[3] environmental influences,[4] pregnancy,[5] caloric intake,[6] practice/training,[7] and psychological stress.
[11] Furthermore, starting from the primary stimulus-response sequence in simple reflexes, the organisms' capacity to correctly detect alterations within themselves and their context depends on the concrete nervous system architecture, which evolves in a particular way already during gestation.
[25][26] The term has since been broadly applied: Given the central importance of neuroplasticity, an outsider would be forgiven for assuming that it was well defined and that a basic and universal framework served to direct current and future hypotheses and experimentation.
[23][35] In the 1960s, Paul Bach-y-Rita invented a device that was tested on a small number of people, and involved a person sitting in a chair, embedded in which were nubs that were made to vibrate in ways that translated images received in a camera, allowing a form of vision via sensory substitution.
[36][37] Studies in people recovering from stroke also provided support for neuroplasticity, as regions of the brain that remained healthy could sometimes take over, at least in part, functions that had been destroyed; Shepherd Ivory Franz did work in this area.
He has made some of "the most ambitious claims for the field – that brain exercises may be as useful as drugs to treat diseases as severe as schizophrenia – that plasticity exists from cradle to the grave, and that radical improvements in cognitive functioning – how we learn, think, perceive, and remember are possible even in the elderly.
Merzenich asserted that, "If the brain map could normalize its structure in response to abnormal input, the prevailing view that we are born with a hardwired system had to be wrong.
There is ample evidence[61] for the active, experience-dependent re-organization of the synaptic networks of the brain involving multiple inter-related structures including the cerebral cortex.
The concept of neuroplasticity is also central to theories of memory and learning that are associated with experience-driven alteration of synaptic structure and function in studies of classical conditioning in invertebrate animal models such as Aplysia.
Robot assisted therapy is an emerging technique, which is also hypothesized to work by way of neuroplasticity, though there is currently insufficient evidence to determine the exact mechanisms of change when using this method.
"Administration of progesterone after traumatic brain injury[67] (TBI) and stroke reduces edema, inflammation, and neuronal cell death, and enhances spatial reference memory and sensory-motor recovery.
In 2009, Lorimer Moseley and Peter Brugger carried out an experiment in which they encouraged arm amputee subjects to use visual imagery to contort their phantom limbs into impossible[clarification needed] configurations.
This experiment suggests that the subjects had modified the neural representation of their phantom limbs and generated the motor commands needed to execute impossible movements in the absence of feedback from the body.
Prolonged nociception from the periphery then elicits a neuroplastic response at the cortical level to change its somatotopic organization for the painful site, inducing central sensitization.
[79] Additionally, chronic pain has been reported to significantly reduce the volume of grey matter in the brain globally, and more specifically at the prefrontal cortex and right thalamus.
His results suggest that meditation may lead to change in the physical structure of brain regions associated with attention, anxiety, depression, fear, anger, and compassion as well as the ability of the body to heal itself.
can "macroscopically imprint a neural network system of spontaneous activity in which the related brain regions become functionally and topologically modularized in both domain-general and domain-specific manners".
[93] In simple terms, brains repeatedly exposed to artistic training over long periods develop adaptations to make such activity both easier and more likely to spontaneously occur.
D.W Zaidel, adjunct professor of behavioral neuroscience and contributor at VAGA, has written that "evolutionary theory links the symbolic nature of art to critical pivotal brain changes in Homo sapiens supporting increased development of language and hierarchical social grouping".
Neuroimaging post music-supported therapy revealed functional changes in OFC networks, with improvements observed in both task-based and resting-state fMRI analyses.
[121] Several studies support the latter idea and found weakened ability in audio distance evaluation, proprioceptive reproduction, threshold for visual bisection, and judging minimum audible angle.
Studies in 2010[124] and 2011[125] using functional magnetic resonance imaging techniques have shown that parts of the brain associated with visual processing are adapted for the new skill of echolocation.
[136][137] The California sea hare, a gastropod, has more successful inhibition of egg-laying hormones outside of mating season due to increased effectiveness of inhibitors in the brain.
Jon Kaas, a professor at Vanderbilt University, has been able to show "how somatosensory area 3b and ventroposterior (VP) nucleus of the thalamus are affected by longstanding unilateral dorsal-column lesions at cervical levels in macaque monkeys.
[148] One recent study of neuroplasticity involves work done by a team of doctors and researchers at Emory University, specifically Donald Stein[149] and David Wright.
[151] Genes that play central roles in synaptic plasticity were the most significantly affected by age, generally showing reduced expression over time.
[citation needed] In one prominent study, neurolinguists used a voxel-based morphometry (VBM) method to visualize the structural plasticity of brains in healthy monolinguals and bilinguals.
[157] However, while traditional antidepressants cause a quick increase in noradrenaline, serotonin, or dopamine, there is a significant delay in their clinical effect and often an inadequate treatment response.
[159] They found a strong inverse relationship between the number of synapses and severity of depression symptoms[160] and discovered that in addition to their neurotransmitter effect, traditional antidepressants improved neuroplasticity but over a significantly protracted time course of weeks or months.
Innovations in this field include vests that convert sound into vibrations for individuals with hearing impairments and advanced prosthetics capable of integrating with neural signals to mimic natural movement.
