Neuroplasticity

Question 1

Term: The ability of neurons to change their functions, chemical profile, or structure for longer than a few seconds

Answer 1

Neuroplasticity

Question 2

3 Mechanisms of Neurplasticity

Answer 2

1. Habituation
2. Experience-dependent plasticity
3. Recovery following injury

Question 3

Term: Decrease in response to a repeated, benign stimulus due to a decrease in synaptic activity between sensory neurons and interneurons

Answer 3

Habituation

Question 4

Describe the effect of absence of the stimulus on habituation

Answer 4

After a period where the stimulus is not applied, the effect resolve or diminish, once the stimulus is reapplied the response will return

Question 5

Describe the effects of prolonged, repeated stimulus on habituation

Answer 5

Can result in more permanent, structural changes – the number of synaptic connections decreases

Question 6

Term: Allows other types of learning to occur by letting people pay attention to important stimulation but “tune out” stimulation that is less important

Answer 6

Habituation

Question 7

Term: Involved with learning and memory

Answer 7

Exeperience-dependent plasticity

Question 8

Term: Persistent, long-lasting changes in the strength of synaptic connections between neurons and within neural networks

Answer 8

Exeperience-dependent plasticity

Question 9

Describe the mechanisms behind Experience-dependent plasticity

Answer 9

1. synthesis of new proteins
2. growth of new synaptic connections
3. modification of existing synapses

Question 10

2 types of Experience-dependent plasticity

Answer 10

1. long-term potentiation (LTP)
2. long-term depression (LTD)

Question 11

Describe how presynaptic and postsynaptic sysnapses change with Experience-dependent plasticity

Answer 11

Pre: through changes in NT release

Post: through changes in receptor density/efficiency

Question 12

Term: “What fires together wires together”

Answer 12

LTP

Question 13

Term: Prolonged stimulus results in growth of new cells/synapses

Answer 13

LTP

Question 14

Term: Receptors englufed resulting in the synapses becoming inactive

Answer 14

LTD

Question 15

Describe the role of astrocytes in Experience-dependent plasticity

Answer 15

Astrocytes modulate NT release and receptor expression at the post-synaptic membrance via the release of gliotransmitters, they may also be responsible for new synapse formation

Question 16

Term: Remembering the 3 things you need to pick up at the store

Answer 16

Working memory

Question 17

Term: Remembering a new phone number 5-10 minutes later

Answer 17

Short-term memory

Question 18

Term: Recall of facts

Answer 18

Long-term memory – Delcarative – Semantic

Question 19

Term: Recall of events

Answer 19

Long term memory – Declarative – Episodic

Question 20

Term: Recall of facts and events

Answer 20

Delcarative Memory

Question 21

Term: Recall of motor skills

Answer 21

Non-declarative – Procedural memory

Question 22

Describe what an injury to an axon in the PNS looks like physiologically

Answer 22

• cytoplasm leaks out
• segments retract from one another
• distal Wallerian degeneration
• glia clean up debris
• cell body undergoes central chromatolysis
• potential synapse degeneration and death

Question 23

Term: degeneration of axon and myelin distally along with mm atrophy

Answer 23

Wallerian degeneration

Question 24

Term: cell body degenerative changes

Answer 24

Central chromatolysis

Question 25

Describe regeneration of axons in the PNS

Answer 25

Regeneration occurs in the form of sprouting of damaged axons which is guided by nerve growth factor produced by Schwann cells and by Bands of Bungner Recover is slow -- 1 mm/day, but can be stimulated by exercise

Question 26

Term: maladaptive rewiring; either alterned/crossed sensations or mm co-contraction

Answer 26

Synkinesis

Question 27

Describe the post injury response in the CNS

Answer 27

The majority of the damage takes hours to days to evolve due to the cascade of cellular events which is why it can take time to see how a pt. will present - white fiber tract damage leads to increased Ca influx - leads to the disruption of axonal transport and results in build up - leads to axonal swelling - leads to axonal retraction ball - leads to chromatolysis and Wallerian degeneration

Question 28

Describe the difference between the physiology behind SCI and TBI

Answer 28

SCI: extent of deficit depends on damage of white tracts and level TBI: interial forces can cause widespread tearing and stretching which can cause diffuse axonal injury (stretched/torn fibers) and widespread neuron disconnect

Question 29

Describe the ability of the CNS to recover

Answer 29

Doesn't occur as well as in the PNS Regeneration is limited by glial scars which release neurite outgrowth inhibitor (Nogo)

Question 30

2 Promising tx for CNS axonal injury

Answer 30

1. Drugs to inhibit Nogo 2. Stem cells

Question 31

4 CNS synaptic changes following injury

Answer 31

1. Recovery of synpatic effectiveness 2. Denervation hypersensitivity (increase in receptors) 3. Synaptic hypereffectiveness (increase NT release) 4. Unmasking/disinhibition of silent synapses

Question 32

Describe Cortical Reorganization

Answer 32

Cortical represenation can be modified by sensory input/experience/learning/injury. Performing a motor skill task regularly can enlarge that area of cortical representation

Question 33

Describe the impact of genetics on cortical reorganization

Answer 33

Those with a BDNF gene have a decreased ability to learn a motor task and had poorer recovery following subarachnoid hemorrhages The implications for PT include: could help direct plan to accomodation or rehabiliation, could also limit the pt. potential due to a stigma of inability to improve

Question 34

2 areas in the adult brain where new neurons are produced

Answer 34

Hippocampus and the wall of the lateral ventricles

Question 35

Describe the issue with naturally occuring neurogenesis

Answer 35

The new neurons/stem cells produced in the brain move to the area of injury but do not survive long enough to resolve the problem

Question 36

Describe how rehabilitation can promote plasticity

Answer 36

1. Intensity (too much to soon can be damaging) 2. Type (task specific!) 3. Amount (early and frequent)