Week 4 content

Question 1

define neuroplasticity

Answer 1

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

Question 2

what are the mechanisms underpinning neuroplasticity

Answer 2

o Habituation
o Long-term potentiation, long term depression
o Cortical reorganisation.

Question 3

define habituation

Answer 3

 A decrease in response to a repeated, benign stimulus
 One of the simplest forms of neuroplasticity
 Cellular mechanisms that are response for habitation are completely understood.

Question 4

define long term potentiation

Answer 4

 “Neurons that fire together, fire together.”
 Glutamate is released from the pre-synaptic neuron, travels across the synaptic cleft, and binds with the NMDA receptors on the post-synaptic neuron.
 In response to repeated activation of NMDA receptors, the AMPA receptors move from the cytoplasm to the membrane where they can act as receptors to the glutamate.
 When this happens, another dendritic spine is created.
 In response to the new dendritic spine, the pre-synaptic neuron changes its structure, and a new synapse is created.
 Long term potentiation is a form of neuroplasticity where neural pathways become stronger due to the creation of new synapses.

Question 5

define long term depression

Answer 5

Neurons that fire out of sync, fail to link.
→ Long term depression is a form of neuroplasticity where neural pathways become weaker due to the loss of synapses.

Question 6

define cortical remapping/reorganization

Answer 6

→ Can sometimes result in unwanted neuroplastic changes (e.g., phantom limb pain).
→ Why do patients feel sensation in their phantom limb when the face skin is stimulated – the imprint from the phantom limb remained therefore creating the sensation where the hand used to be.

Question 7

define motor learning

Answer 7

→ Acquisition of motor skills, or the reacquisition of skills following injury, disease and the like.

Question 8

performance vs learning

Answer 8

→ Performance = observable behaviour, execution of a skill at a specific time and in a specific location, may not be due to a practice, may be influenced by performance variables.
→ Learning – inferred from performance, relatively permanent, due to practice, not influenced by performance variables.

Question 9

what are the stages of learning according to Fits and Posner

Answer 9

1. Cognitive stage – most neural activity
2. Associative stage – less neural activity
3. Autonomous stage – least neural activity.

Question 10

what is the cognitive stage

Answer 10

The cognitive stage is the beginner’s level of skill acquisition. This stage is appropriately named as the focus is on mental concentration and the thought processed involved in understanding and processing new information, before a new skill can even be attempted.

Question 11

associative stage

Answer 11

During the associative stage the performer is learning how to perform the skill well and how to adapt the skill. At this stage the performer is attempting to translate declarative knowledge into procedural knowledge.

Question 12

autonomous stage

Answer 12

The final stage is the autonomous stage. This phase involves further practice of the skill in order to enhance performance so that it becomes automatic. The learner has internalised the skill and is able to perform it with minimal cognitive monitoring.

Question 13

neural recovery post injury in the CNS and PNS

Answer 13

→ In the CNS – if neurons are damaged, they do not regenerate.
→ In the PNS – if cell body isn’t injured than the neuron can regenerate (if injury is only to axon). If cell body is injured than cell will die.

Question 14

why can cell regenerate in the PNS

Answer 14

because debris from damaged axons is cleared much quicker and efficiently compared to the CNS.

schwann cells aid axon regeneration whereas oligodendrocytes inhibit axonal regeneration.

Question 15

what happens when as axon is injured

Answer 15

→ Wallerian degeneration – axon terminal degenerated (distal to cell body degenerates.), myelin breaks down and forms debris, cell body undergoes metabolic changes, presynaptic terminal retract, post synaptic cells degenerates.
→ This process of degeneration occurs in both CNS and PNS – but is much faster and more efficient in PNS.
→ Pictures 1-3 = degeneration
→ Pictures 4-7- =- regeneration

Question 16

degeneration and regeneration process

Answer 16

1. Schwann cells demyelinate and convert into ‘repair SC’.
2. Repair SC disintegrate distal to cut axon site.
3. Repair CS clear axon and myelin debris.
4. SC form regeneration tracks.
5. SC proliferate and promote axonal regrowth.
6. SC remyelinate regenerated axons.

Question 17

what are the principles of neuroplasticity

Answer 17

1. Use it or lose it.
2. Use it and improve it – practise improves ability to perform skill.
3. Specificity – must train the skill you want to improve (make the skill training specific).
4. Repetition matters – a new skill needs to be practised.
5. Intensity matters – tasks must be performed at an adequate intensity to drive neuroplastic improvements.
6. Time matters – maximise the 3-month period post injury (early rehabilitation is more beneficial than delayed rehab).
7. Salience matters – training task must be meaningful, i.e. – training Broca’s area is important to a patient because speaking is a valuable skill for that patient.
8. Age matters – neuroplasticity is much greater in younger people than older people, therefore they undergo greater neuroplastic changes.
9. Transference – the idea that being better at one skill helps someone learn another skill.
10. Interference – contextual interference is the idea that if you train lots of different things at the same time, ultimately your learning may be better (even if your performance suffers during the training session).

Question 18

what are the motor learning principles

Answer 18

Practise specificity -
Intensity
Distribution of practise - distributed is more benficial
Practise variability - HIGHER contextual interference may have poorer performance during practice, but allows better performance during retention and transfer tests where LOWER contextual interferences means learners overestimate their learning.
Motor imagery - physical practise is better than mental practise.