Neuroplasticity

NEUROPLASTICITY

Adeagbo, Caleb AdewumiPhysiotherapist

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Outline • Historical background• Introduction• Definition• What influences Neuroplasticity• Organizational adaptation in

Neuroplasticity• Determinants of Neuroplasticity• Application of Neuroplasticity• Conclusion

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Historical background•  William James presented the first

theory of Neuroplasticity around 120 years ago, in his book “Principle of Psychology”

• The first documented person known to use the term Neuroplasticity was a Polish Neuroscientist named Jerzy Konorski, in 1948.

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•  Donald Hebb a Canadian Psychologist put forth this idea in the mid 1900's that “neurons that fire together wire together”.

• Paul Bach-y-Rita was one of the first neuroscientists to actually create modern applications for what we studied about in the field of Neuroplasticity.

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• Edward Taub is another very notable scientist that helped to further the study of Neuroplasticity and also developed actual applicable treatments for patients.

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Introduction• Neuroplasticity is also known as brain

plasticity, cortical plasticity• Derived from root words neuron and

plastic• Neuron = nerve cell• Plastic = to mold, sculpt or modify • Neuroplasticity takes place

throughout life• Occurs in the Nervous System

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• Neuroplasticity causes change in the speed of transmitting and processing of information in the nervous system.

• Neuroplasticity causes specialization of the nervous system

• Neuroplasticity is a general term used to encompass:

i. Habituationii. Learning and memoryiii. Cellular recovery after injury

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Habituation• It is one of the simplest forms of

Neuroplasticity. • It is the decrease in response to a

repeated, benign stimulus• It is short-term. Generally after

seconds of rest the effects of habituation are no longer present. However with prolong repetition more permanent structural, functional and chemical profile changes occur.

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Learning and memory

• Involves persistent, long lasting or permanent structural, functional and chemical profile changes.

• Repetition is the key factor involve in learning and memory

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Cellular recovery after injury

• Injuries that severe the axons causes degeneration

• Injuries that destroy the cell body of a neuron lead to death of the cell

• When a nerve cell die the nervous system promotes recovery by altering its structure, function and chemical profile

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Definition

• Neuroplasticity is the ability of the nervous system to adapt its structure, function or chemical profile to new situations which could emerge from developmental, environmental and pathological influences.

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What influences Neuroplasticity • Developmental influences• Environmental influences• Pathological influences

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Developmental influences• Maturation of the nervous system.At birth, the human brain weighs

approximately 350 grams.By the first year. the brain weighs

approximately 1000 grams.The adult brain weighs 1200-1400

grams

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• The development of neurons in the nervous system involves the following processes:

1. Proliferation/Neurogenesis2. Migration3. Differentiation4. Myelination5. Synaptogenesis

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Environmental influences

• Environment have effect on the nervous system function.

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Pathological influences• Diseases or lesion of nervous

system which include:i. Tumorsii. Infectionsiii. Exposure to toxic substancesiv. Degenerative diseasesv. Traumavi. Congenital defectsvii. Lesion of circulatory system

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Organizational adaptation in Neuroplasticity• Anatomical changes• Physiological changes• Biochemical changes

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Anatomical changes

• Structural changes in the nervous system:

i. Increase in number and density of neuronal processes through dendritic and axonal sprouting

ii. Neurogenesisiii. Increase number of synapses

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Dendritic and axonal sprouting

• Neural process produces new nerve ending essential to connect to nerve ending of the neurons.

• It occur in all part of nervous system

• But more elaborate in PNS

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Neurogenesis

• New cells are added to nervous system

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Increase number of synapses• This increases throughout life• There are about 2,500 synapses

per neuron at birth. This increase dramatically to 15,000 in the first 3 years of life

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Physiological changes• Functional reorganization in the

nervous systemi. Strengthening the existing

numbers of connectionsii. Reorganization of the cortical

mapiii. Synaptic pruning

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Strengthening the existing numbers of connections

• Improvement in the synaptic efficacy

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Reorganization of the cortical map

• Undamaged areas of the brain takes the functions of the damaged area of the brain

• Development of the cortical map

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Cortical map of a normal person

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Cortical map of a Drummer

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Cortical map of a Football player

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Synaptic pruning• At birth, each neuron in the cerebral

cortex has approximately 2,500 synapses.

• By the time an infant is two or three years old, the number of synapses is approximately 15,000 synapses per neuron.

• Then unused synapses are deleted rendering the weaker junctions to wither and allow strengthening of the stronger synapse.

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• Neurons must have a purpose to survive.

• Without a purpose, neurons die through a process called APOPTOSIS in which neurons that do not receive or transmit information become damaged and die.

• Apoptosis is “programmed cell death”• It takes place to avoid redundancy in

the nervous system.

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Biochemical changes

• Neurochemical changes in the nervous system.

i. Increase production of neurotransmitters

ii. Decrease production of neurotransmitters

iii. Metabolic changes

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Increase production of neurotransmitters

• Excitatory neurotransmitters are increase where movement is expected

• Inhibitory neurotransmitters are increase where movement is not expected

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Decrease production of neurotransmitters

• Excitatory neurotransmitters are decrease where movement is not expected

• Inhibitory neurotransmitters are decrease where movement is expected

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Metabolic changes

• Involves the fluctuation in the rate at which nutrients are consumed by a part of the nervous system

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Determinants of Neuroplasticity

• Age• Severity of lesion• Comorbidities• Part of the lesion• Availability of metabolites • Vascular supply

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Application of Neuroplasticity• The earlier the better• Environment• Repetitive task training• Intensive task training• Task oriented• Neuroflexibility

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Conclusion • Physiotherapist must focus on

recovery rather than compensation.• There is sufficient evidence that the

nervous system not only develop and mature during adolescence but also recovers from serious diseases and injuries.

• Appropriate neurorehabilitation approach should be use to achieve Neuroplasticity

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NEUROPLASTICITY

•Use it or lose it•Use it and improve it

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THE END....THANK YOU

FOR LISTENING

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