Neural Plasticity

Question 1

What changes with learning?

Answer 1

• Movement
• Attention
• Error Detection and correction
• The nervous system

Question 2

What is neural plasticity?

Answer 2

• Living nervous system
• Capacity of CNS to undergo changes in function and structure in response to use.
• Changes occur throughout the nervous system
• Occurs in motor learning and recovery of function
• May be favorable or unfavorable

Question 3

Neural Plasticity: Basic Concept

Answer 3

Use -> Functional Change -> Structural Change

Question 4

Types of Plasticity
Where do they occur?

Answer 4

• Habituation and Sensitization
• Occur in reflex pathways (non-declarative/implicit learning)

Question 5

Habituation

Answer 5

• Decreased responsiveness as a result of repeated exposure
• Decrease in synaptic activity between sensory and motor neurons that can lead to long term reduction in number of synapses

EPSP = Excitatory Post Synpatic Potential

Question 6

Sensitization

Answer 6

• Increased responsiveness as a result of exposure to a stimulus
• Increase in synaptic activity between sensory and motor neurons leads to long term increase in number of synapses

Question 7

____ may dictate whether there is sensitization vs habituation

Answer 7

Perception of potential harm

Ex: Pain

Question 8

Implicit Learning

Answer 8

• (Procedural and Associative)
• Learning to predict relationships and learning “automatic” sequences/patterns over time
• i.e. Trial and error (a.k.a. sensorimotor mapping over time)
• Involves Cerebellum and: premotor, sensorimotor, parietal cortices, BG

Non declarative

Question 9

What are the short term plasticity changes?

Answer 9

Change in synpatic efficency

Question 10

What are the long term plasticity changes?

Answer 10

• Formation of new synaptic connections
• Same idea as habituation/sensitization

Question 11

What cells are important for long term plasticity changes? What is the functions of the cells function?

Answer 11

• Cerbellar climbing fibers
• Cerebellar purkinje cells
• Cerebellar mossy fibers

Ex: Motor Learning

Question 12

Explicit Learning

Answer 12

• Requires awareness & attention, results in knowledge expressed consciously
• Involves the temporal lobe and:
• Sensory association cortex, hippocampus
• Long term potentiation (similar to sensitization)

Declarative

Question 13

Role of cortical areas

Answer 13

• Cortex more involved early in learning
• For complex motor skills:
  – Repetition improves synaptic efficiency between sensory and motor cortices
  – With repetition, use sensorimotor cortex less and thalamocortical pathways more

Question 14

Initial phases of learning activation and location

Answer 14

• Widely distributed activation
• Bilateral cortex, basal ganglia, cerebellum

Question 15

Later phases of learning activation and location

Answer 15

• Less cortical activity & more subcortical
• Basal ganglia, cerebellum, thalamus

Question 16

How is plasticity influenced by age?

Answer 16

learning requires more brain activity and more time/repetition

Question 17

How is plasticity influenced by pathology

Answer 17

Require more brain activity for even simple tasks

Question 18

____ of post concussion syndrom is correlated with in creased brain activity

Answer 18

Severity

Question 19

What are the three types of nerve damage?

Answer 19

• Neuropraxia
• Axonotmesis
• Neurotmesis

Question 20

Neuropraxia

Answer 20

Transient interrupted signal transmission

Question 21

Axonotmesis

Answer 21

Axon damage only

Question 22

Neurotmesis

Answer 22

Damage to axon and sheath = worst case scenario

Question 23

How does degeneration/regeneration of a nerve work after injury?

Answer 23

• Anterograde degeneration: (occurs after neurotmesis) Distal to lesion axon degenerates to end
• Retrograde (proximal) degeneration: dying back toward cell body proximal of lesion

Question 24

Degeneration/Regeneration after injury - Timeline

Answer 24

• Minutes after injury – swelling and myelin retraction from axon
• 2-3 days myelin begins to be digested
• By day 6 (maybe earlier), glial cells form a tube for possible regeneration
• Axonal sprouts may find adjacent tube and may regenerate

Question 25

Regeneration of nerves occurs in the ____

Answer 25

PNS CNS is mysterious and not understood.

Question 26

What happens when there is an injury to the CNS?

Answer 26

* Can directly damage the neuron * Neuronal function often indirectly affected by impaired: -- Cerebral blood flow -- CSF control -- Cerebral metabolism * These are usually transient and quickly reverse

Question 27

Injury to the CNS - Transient Changes

Answer 27

* Loss of function in structurally intact brain area because of loss of input (**diaschisis**) -- Can be due to decrease in blood flow and metabolism * Cerebral edema commonly occurs after brain injury. -- May lead to compression of axons and blocking of conduction

Question 28

Recovery of Function - What are the 4 Cellular Responses

Answer 28

* Altered synaptic efficency * Recruitment/Unmasking silent synapses * Neural Regeneration * Collateral Sprouting

Question 29

Recovery of Function - Altered Synaptic Efficency

Answer 29

Change in the balance between inhibition and facilitation at the synapse

Question 30

Recovery of Function - Recruitment/Unmasking of synaptic synapses

Answer 30

Due to experience or lesion

Question 31

Neural Regeneration

Answer 31

* Synaptogenesis (SLOW) * The regeneration or formation of new synapses * More sure of this in PNS than CNS currently

Question 32

Collateral Sprouting

Answer 32

* Sprouting (SLOW) * Neural growth and regeneration after injury. * Collateral sprouting is the branching outgrowth of new axon terminals from uninjured axons.

Question 33

Cortical Maps after CNS lesions

Answer 33

* Reorganization of affected hemisphere -- Primary motor cortex lesions = activation of PMA and SMA -- Adjacent cortex may take over as well * Uncrossed motor pathways may assist * Cross modality-processing -- In absence of one sensory stimuli, we become responsive to others * Functional recovery is better when these changes are only temporary

Question 34

A peripheral injury/pain leads to ____ of sensorimotor representations.

Answer 34

smudging

Question 35

Cortical Changes after Amputation

Answer 35

* Intact muscles become more active with lower threshold and over wider area in cortex * In humans, Stimulation of face and upper limb evoke phantom limb pain, suggests remapping of somatosensory system.

Question 36

The amount of cortical shift varies with length of ____ pain

Answer 36

chronic low back

Question 37

Role of Cerebellum - Recovery of Function

Answer 37

* Cerebellum is very important to motor recovery, basically the same role as in motor learning * Individual constraints are altered, so… * **Recovery can be viewed as motor learning with a new set of individual abilities/constraints**

Question 38

Behavorial Substitution vs Compensation

Answer 38

* Substitution for long term * Compensation for short term, then retrained back to normal function

Question 39

Strategies to promote neuroplasticity

Answer 39

* Practice! * Need a sensory rich environment * Sensory stimulation helps with skill acquisition and increased task function (electrical stimulation)

Question 40

____ is associated with cortical reorganization

Answer 40

Skill learning * simple exercise and strength training is not enough (need sensory rich, task specific and lots of practice)

Question 41

What are the 10 variables that affect plasticity?

Answer 41

* Use it or lose it * Use it and improve it * Specificity * Repeition matters * Intensity matters * Time Matters * Importance matters * Age matters * Transference (one trainined experience, enhances others) * Interference

Question 42

How can Cardiovascular exercise promote neuroplasticity?

Answer 42

* Moderate to Hig intensity releases BDNF * Before or **after** practice * Singe/Acute and Chronic Effects

Question 43

Can genetic play a role in neuroplasticity?

Answer 43

Yes, but not much is known. May be positive or negative on plasticity.