Neuroplasticity

Question 1

Neuroplasticity is the CNS mechanism by which… (2)

Answer 1

The brain encodes experience and new behaviors.

The brain relearns lost behavior when damaged in response to rehab.

Question 2

Plasticity underlies…

Answer 2

ALL learning

Question 3

What is the most important variable to learn motor skills and promote neuroplasticity

Answer 3

Skill acquisition through PRACTICE

Question 4

Practice terminologies related to plasticity (2)

Answer 4

Exercise dependent plasticity

Experience-dependent plasticity

Question 5

Principles of Exercise-Dependent Plasticity (5)*

Answer 5

Use it and improve it
Specificity
Repetition Matters
Intensity Matters
Salience Matters

Question 6

Use it and improve it

Answer 6

training that drives a specific brain function to lead enhancing that function

Question 7

Specificity

Answer 7

Nature of training experience dictates nature of the plasticity

Question 8

Repetition Matters and Intensity Matters

Answer 8

Induction of plasticity requires sufficient repetition and intensity

Question 9

Salience Matters

Answer 9

The training experience must be sufficiently salient to induce plasticity.

Question 10

Jenkins Repetition study on monkeys. What is used, how results are measured, results…

Answer 10

Pellet is put on a rotation disk and the monkeys have to get the pellet with their 2nd and 3rd digits. Intracortical micro stimulation is used to see how much stimulation of their hand is changed after doing tasks. Color code is seen to represent the movement. Results show that stimulation expanded with the digits after differential stimulation.

Question 11

Task difficulty study on monkeys

Answer 11

Monkeys grab food from a small well/small well training and a large well/large well training over 12 days. Intracortical microstimulation is used on which shows a color code change of which part of the upper extremities is used more in pre-and post training. Graph is used to measure how much items they retrieved and how efficient it is. Results show that monkeys who retrieve food from the small well over time are able to retrieve more food using less forearm muscles and use more digits and motor cortex instead. There is not much change of muscle use and large improvements in retrievals for large well trained monkeys.

Question 12

Conclusions from Task Complexity experiment on rats (3)

Answer 12

Functional reorganization of the motor cortex is:

• Skill dependent rather than use dependent
• Skill acquisition more important than repetition
• Skill acquisition more important than strengthening

Question 13

What induces Cortical Map Reorganization in Humans

Answer 13

Skill learning, not strength training induces cortical reorganization

Question 14

Transcranial Magnetic Stimulation TMS

Answer 14

Magnetic coil put over head to induce a magnetic field which put a secondary coil current in the opposite direction in the motor cortex to depolarize the neurons.

Question 15

TMS effect and use of electrodes

Answer 15

Contraction of contralateral muscles.

Electrodes over peripheral muscles measures motor evoked potentials (MEPs)

Question 16

MEPs in Skill training vs Strength training

Answer 16

MEPs improve over time in skill training while it declines or barely improves in strength training

Question 17

Spontaneous neural recovery

Answer 17

after injury, brain plasticity attempts to restore brain independent of rehab.
The ability ot regain motor and speech

Question 18

Mechanisms for spontaneous recovery (3)

Answer 18

Lessening of edema
Reestablish pre-morbid neurotransmitter levels
Reabsorption of blood in hemorrhage

Question 19

Diaschisis

Answer 19

The selective disruptive effect of a focal lesion on the operations of areas with which it was structurally and functionally connected.
Simple definition: Damage to one brain area can produce loss of function in regions adjacent to or remote from but connected to the primary site of damage

Question 20

Time period of Spontaneous Recovery for brain injury and CVA

Answer 20

1 year for brain injury
6 months for CVA

If a person cannot make changes to improve themselves in that time period, permanent damage happens.

Question 21

Small/large well experiment on post-infarct monkeys results:

Answer 21

Monkeys in small well group use more flexions per retrieval.

3 months post- infarct, the hand stimulation/representation grew in the rehab group but declined in the non-rehab group. This shows rehab is important for post-infarct patients.

Question 22

Neuroplasticity and compensation on rats with strokes findings (2)

Answer 22

1. Rats use unaffected side only. Robust plasticity of dendrites and synapses was seen in the contralesional motor cortex.
2. Compensation with the unaffected sided reduces neuronal activation in the infarcted cortex. The possibility of repairing the impaired limb worsens.

Question 23

What does compensation interferes with and what it means?

Answer 23

With recovery, which is why there are persistent behavioral deficits after brain injury.