Chapter 1.

Question 1

What is plasticity?

Answer 1

The capacity of the nervous system to adapt to functional demands and therefore the system’s ability to reorganize.

Question 2

How has the view of the brain changed recently from Merzenich et al 1991

Answer 2

Acknowledged that brain processes are continuously remodelled by our experiences throughout life.

Question 3

What are the mechanisms of brain plasticity?

Answer 3

capacity for neurochemical, neuroreceptive and neuronal structural changes

Also parallel and distrubuted nature of brain organisation - intracortical axonal collaterals

Question 4

What affects the amount of cortex for an activity?

Answer 4

Competition for cortical territory appears to be use dependent - Monkeys eating with first 3 fingers, expansion of area of cortex that serves these fingers (after several thousand repetitions)

Question 5

What changes in the nervous system have been demonstrated in studies involving the training of animals?

Answer 5

Strength of existing neuronal connections

Emergence of new connections

Question 6

What did teaching complex skills that increased demands of repeated physical activity stimulate in rats?

Answer 6

angiogenesis

synaptogenesis

Question 7

What changes are seen in the first few weeks of strength training?

Answer 7

increase in electrical activity in muscle, which precedes a significant change in muscle size

Question 8

What increases after strength training and decreases after a period of inactvity?

Answer 8

descending drive on to spinal motor neurons

Question 9

What are the physical changes of plasticity after a brain lesion?

Answer 9

Axonal and dendritic sprouting

Question 10

What are physical changes as a result of plasticity after a brain lesion?

Answer 10

Sensitivity of certain sites to certain neurotransmitters

Question 11

What is recovery associated with?

Answer 11

Bilateral activation of the motor system
with use of the ipsilateral pathways and recruitment of additional motor areas.
Activation of attentional and intentional states also appear to be important

Question 12

What does early spontaneous recovery after an acute lesion represent?

Answer 12

Return to function of undamaged parts of the brain, the capacity of which is diminished by reparative processes for example, resolution of local factors such as oedema and absorption of necrotic tissue debris and opening of collateral channels for circulation to the lesioned area

Question 13

When does early spontaneous recovery occur?

Answer 13

relatively short period, 3-4 weeks

Question 14

What is diaschisis ?

Answer 14

Sudden functional depression of brain distant to the lesion site, with reduced blood flow and metabolism - underlying mechanism unknown.

Question 15

What time of recovering occurs after 3-4 weeks?

Answer 15

Must be due to other mechanisms than spontaneous recovery - labelled Plasticity.

• Unmasking of pathways previously functionally inactive
• Sprouting of fibres from surviving nerve cells with formation of new synapses
• and reduncancy in neural circuitry - i.e multiples parallel pathways subserving similar functions

Question 16

What may occur in the absence of appropriate rehab?

Answer 16

Potential for new, maladaptive connections . May underlie the development over time of stiff or spastic muscles and the use of inappropriate force by intact muscles.
In time, maladaptive changes will occur in MSK system

Question 17

What may be caused by an overly assistive and protective environment?

Answer 17

Learned helplessness
symptoms of passivity and poor performance in individuals where they have little control over their role in the institutional environment