OTM 507 Neuroplasticity 8.27.19

Neuroplasticity

The ability of neurons to change their function, chemical profile (amount and types of neurotransmitters produced), and/or structure

This is why therapy is effective

- new learning

- relearning

- memory

Includes: habituation, experience-dependent plasticity, and cellular recovery after injury

Habituation

A decrease in response to a repeated, benign stimulus

- one of the simplest forms of neuroplasticity

- 'get used to it'

- allows for multitasking

In PT and OT, __ techniques are intended to decrease neural responses to a stimulus

- visual/vestibular disorders

- complex regional pain syndrome

- autism (tactile defensiveness)

Experience-Dependent Plasticity (learning and memory)

Involves persistent long-lasting changes in the strength of synapses between neurons and within neural networks

With repetition of a task, the number of active regions of the brain is reduced

- "learning curve"

- the brain initially works harder and when skill is learned less brain activity is required

Astrocytes contribute to this

- influence synapses through modulating neurotransmitter release and receptor ability at the postsynaptic membrane

- support neurons after injury (new synapse formation after injuries like stroke)

PT and OT important for facilitating new learning patterns through this mechanism

Cell Body

Injury to the __ __ of a neuron results in cell death

Axonal inury

Damage is usually on a cellular level

- the __ swells and breaks and the cell body dies

No __ regeneration in the CNS, growth inhibiting factors released

Sprouting may occur

- collateral: neighboring axons branch to reinnervate

- regenerative: axon and target cell are damaged, so the axon branches to a new target

Exercise after injury stimulates regeneration

Recovery occurs when:

- edema(fluid buildup) /ischemia is reduced

- other receptor sites become more sensitive

- increased neurotransmitter released through intact __ branches

- silent, or unused, synapses are now used

- neurogenesis through stem cells

Collateral Sprouting (Axonal injury)

Which type of sprouting is occurring?

Regenerative Sprouting (Axonal injury)

Which type of sprouting is occurring?

Cortical areas

Routinely adjust the way they process info

Also have the ability to develop new functions

Cortical Map

Cortical representation areas; functional areas of the brain that respond to sensory or muscles stimulation

- if a person regularly performs a skilled motor task the cortical representation of that area will be enlarged

Reorganization of cerebral cortex

Brain activity shifts surrounding areas

- explains stroke recovery and why other senses are more sensitive when others are delinquent

Metabolic effects (of brain injury)

Following brain injury

Neurons are deprived of oxygen for a prolonged period of time and die without regenerating

- drugs are used to minimize detrimental effects

no (metabolic effects of brain injury)

Do any drugs cure stroke, TBI, or neurodegenerative diseases?

Rehabilitation

This is influenced by the intensity and timing of rehab

- early rehabilitation is necessary for improved outcomes

- avoid bed rest (other functioning areas of brain may suffer)

Task specific training for normal motor patterns

Constraint induced movement therapy

Often a treatment in stroke. The unaffected limb is constrained

- forcing the affected limb to function

- allows for functional reorganization

Avoid intense __ __ __ __ initially after injury because it can increase damage