Chap 25: Plasticity

Question 1

What are the first 5 principles of plasticity ?

Answer 1

1. it is common to all nervous systems
2. Occurs at many levels
3. There are two kinds of plasticity as a result of experience
4. Behavioral changes correlate to plastic changes
5. Experience-dependent changes interact

Question 2

What are the last 5 principles of plasticity?

Answer 2

6. related to experiences that are relevant to the animal
7. it is age dependent
8. is it time dependent
9. related to the intensity and frequency of experiences
10. can be maladaptive

Question 3

Principle 2: At what levels can plasticity be observed ?

Answer 3

1. behavior
2. neural imaging
3. cortical maps
4. physiology
5. mitosis
6. molecular structure
7. synapses

Question 4

Principle 2: Describe Cortical Maps

Answer 4

maps that provide topographic representations of the external world
- motor training can increase motor maps components
- for example, a pianist has larger cortical representation for musical abilities

Question 5

Principle 2: Describe the level of synapses and mitosis

Answer 5

synapses
- plasticity changes in the arborization of dendrites
Mitosis
- olfactory bulbs, hippocampus and striatum undergo cell reproduction throughout life

Question 6

Principle 2: Describe the level of the molecular structure

Answer 6

Study on rats
- rats placed in complex environments activate more than 100 genes in response to the experience

Question 7

Principle 3: What are the 3 types of plasticity from experience ?

Answer 7

1. Experience-expectant
2. Experience-Experience-dependant

Question 8

Principle 4: Describe the correlation between plasticity and behavior

Answer 8

synapse number may increase for one learned behavior, but it can decrease for another

Question 9

Principle 5: Describe how various experiences interact with plasticity

Answer 9

• complex environments may alter plasticity but it can be inhibited through early exposure to stimulant drugs
• affects the frontal lobes principally

Question 10

Describe principle 6

Answer 10

• behaviors can be learned more readily (plasticity responds best) to behaviors that are relevant to an animal
• for example, food aversion is easily learned while the quadric formula is not

Question 11

Describe principle 7, 8 and 9

Answer 11

• plasticity is dependent on age, and time and frequency and intensity of experiences

Question 12

Describe principle 10

Answer 12

• exposure to drugs can also negatively alter brain plasticity

Question 13

What is the sequential process of brain injury in stroke ?

Answer 13

1. changes in ionic balance
2. changes in transmitters: glutamate is released and calcium channels remain open
3. Toxic levels of calcium enters the cell
4. alteration in protein production
5. tissue becomes inflamed threatening cellular integrity

Question 14

Describe the recovery of the motor cortex

Answer 14

1. reflexes return
2. rigidity
3. grasping
4. sequential movement of the shoulder elbow, wrist and then hand (develops outward)

Question 15

What is the likelihood of recovery from the 4 main aphasias ?

Answer 15

1. Conduction: 60-100%
2. Broca’s: 20%
3. Wernickes: 60%
4. Global: <10%

Question 16

What variables increase the likelihood of recovery as discovered from functional imaging ?

Answer 16

• most likely to recover if you are a young women, left-handed, intelligent and optimistic

Question 17

Describe the treatment of stroke

Answer 17

• must administer tPA’s within 3 hours of stroke onset, after receiving CT or MRI to confirm the stroke is not hemorrhagic

Question 18

What is constraint-induced therapy ?

Answer 18

immobilizing the unaffected limb and forcing the injured limb to participate in movement thus facilitating recovery

Question 19

In deep brain stimulation, stimulation of which brain regions are associated with improvements for which disorders ?

Answer 19

stimulate the:
- sub thalamic nucleus/globus pallidus for parkinsons
- striatum or sub thalamic nucleus for depression
- fornix/hippocampus for Alzheimers