Lecture 3

Question 1

Monkey Stroke Study

Answer 1

Nudo
compared changes in cortical
motor representations among three groups
of monkeys: control, spontaneous recovery, rehab
In the spontaneous recovery group -infarct no training-
hand and digit cortical areas surrounding the lesion decreased when compared to the control animals
In the rehabilitation group-
infarct - training - hand and digit cortical areas did not
differ from the controls
training helped prevent cell death
Nudo has suggested that the rehabilitative
training prevented the loss of cortical areas
His work provides evidence in an animal model that the motor cortex is alterable not only in normal animals but in those with brain pathology

Question 2

Nudo Stroke Study Results

Answer 2

Nudo has suggested that the rehabilitative
training prevented the loss of cortical areas

His work provides evidence in an animal model that the motor cortex is alterable not only in normal animals but in those with brain pathology

Question 3

Brain Post Injury

Answer 3

Rewired System
There are more widespread changes that occur post injury. He has shown that there are modifications in the intracortical pathways between the primary motor areas, the premotor areas and the primary sensory areas.

He is saying that plasticity post injury is not just a local phenomenon but also involves connections to other areas, suggesting that we need to think of the
post-injury brain – not just as a brain with a lesion but as a rewired system

Question 4

Drug for Neuroplasticity Study

Answer 4

Jeff Kleim
Use of drugs that promote plasticity.
Administration of the experimental drug Rolipram helped to improve the reaching performance in the rats post infarct
An increase in the cortical area around the infarct.
Did not work unless accompanied by motor skill training

Question 5

Estim to promote neuroplasticity

Answer 5

What happens if you pass electrical current directly on to the rat’s brain while they are being rehabilitated.

Animals receiving electrical stimulation to the brain improve faster and reached a higher end point in terms of percent of successful reaches

Brain areas around the infarct were preserved with changes in the cortical maps.

Question 6

PET Scan Studies

Answer 6

Frackowiak & Chollert
To look at changes in regional blood flow.

Changes in regional blood flow reflect increased neuronal metabolism, and

Neuronal metabolism and functional activity are highly correlated

In recoverd fingers- contralateral side of brain is more active than ipsilateral side of brain but there is much more activity on ipsilateral side in recovered fingers than in a normal finger

Some recovery due to ipsilateral cortex working more
ipsilateral cortex after stroke shows more activity, helping drive recovery
Have also seen as recovery of function occurs, amt of activity in ipsilateral cortex decreases- it seems to be a mechanism that decreases once there is a better recovery

Question 7

Braile Study

Answer 7

Pasqual Leone
Used TMS to look at cortical reorganization of 1st dorsal interossei and abductor digiti minimi
Saw that the representation of index finger was much larger in hadn they use to read braile than in the other hand
Abductor was same in both- bc abductor is passive
More proof of use it and improve or lose it

Question 8

Principles of Experience –Dependent Neural Plasticity

Answer 8

1. Use it or lose it
2. Use it and improve it
3. Specificity
4. Repetition Matters
5. Intensity Matters
6. Time Matters
7. Salience
8. Age Matters
9. Transference
10. Interference

Question 9

Use it or lose it

Answer 9

suggests that neural circuits not actively engaged in task performance for an extended period of time tend to degrade.

Question 10

Use it and improve it

Answer 10

suggests that training can protect neurons and networks that might be otherwise lost after injury
Use of a body part enhances its function - representation areas can either increase or decrease depending upon use.

Question 11

Specificty

Answer 11

indicates mere repetition of a movement that is already learned does not lead to changes in the motor cortex – the practice has to be associated with the acquisition or reacquisition of a novel or lost skill.

Question 12

Repetition Matters

Answer 12

– continued repetition of the newly learned task is required to drive the plasticity. Lasting - long term potentiation of synaptic responses require numerous practice sessions

Question 13

Intensity Matters

Answer 13

implies that the training must be progressive - must be continually modified so that the activity is dynamic and requires increased skill levels.

Question 14

Time Matters

Answer 14

– during motor skill training – gene expression precedes synapse formation which in turn precedes motor map reorganization. (Kleim et.al 1996).

Question 15

Salience Matters

Answer 15

suggests that in order to maximize activity-dependent neural plasticity - training must be functionally relevant and significant to the individual

Question 16

Age Matters

Answer 16

it has been shown that the aging brain has the capacity to demonstrate neural changes related to intensive activity – though the changes may not be as profound as those observed in younger brains.

Question 17

Transference

Answer 17

refers to the ability of plasticity within one set of neural circuits to promote concurrent or subsequent plasticity

Question 18

Interference

Answer 18

refers to the ability of plasticity within a given neural circuit to impede the induction of new plasticity within that circuit

Question 19

CIMT authors

Answer 19

Leipert;Taub;Wittenberg

Question 20

Mudie - bilateral arm training

Whitall - BATRAC

Answer 20

Ipsilateral hemisphere can contribute to motor control

Question 21

Ridding - peripheral nerve stimulation (TMS, NMES)

Answer 21

Sensory stimulation enhances plasticity

Question 22

Genetics in Motor Recovery after Stroke

Answer 22

Someone with vall66met variant- have decreased levels of bdnf, therefore don’t respond to motor learning paradigms as well
They have decreased levels of the brain derived neurotrophic factor and that affects their recovery from brain damage.

Question 23

increase BDNF

Answer 23

Evidence is beginning to develop that suggests that aerobic exercise may be a valuable intervention for improving/ increasing levels of BDNF through aerobic exercise

Question 24

Neural Plasticity and Degenerative diseases

Answer 24

In animal models - Casting of the affected limb for 7 days – led to increased behavioral deficits and increased dopamine loss compared to animals that were not casted (Tillerson 2001)

Animals that initiated intensive exercise within 5 days of the experimental lesion showed improved movement speed and balance.

Although the loss of dopamine remained similar in the two groups there was an increased availability of synaptic dopamine – including increased release and reduced uptake

Question 25

Why might exercise have an effect on dopamine availability

Answer 25

Exercise may protect dopaminergic cells by inducing mild cellular stress which elevates the intracellular response to stress and increased the release of neurotrophic factors.

Exercise has been proposed as neuroprotective in PD - an ongoing clinical trials are examining the feasibility of using high-intensity exercise to modify the motor symptoms in PD

Question 26

Neural Plasticity and MS

Answer 26

Some recovery of the affected hemisphere however did not show a decrease in bilateral motor activation in the primary motor cortex
Not much MS research because of the fatigue component

Question 27

Spinal cord plasticity

Answer 27

Replace cells , neurotrophins and chemical messengers

Re-grow axons dendrites and synaptic
connections

Retrain circuits, networks and behaviors

Question 28

Barbeau and Rossignol

Answer 28

Cat spinal cord treadmill training

Question 29

Locomotor Control- most basic level

Answer 29

operates automatically without consciuos perception

interneurons in gray matter of spinal cord- CPGs

Question 30

Locomotor Control influences

Answer 30

Spinal network generates specific
muscle specific spatio-temporal
pattern - basic stepping sequence
Is influenced by sensory feedback from joint, muscle, and skin receptors as well as higher brain centers
Sensory inputs adjust the muscle activiation pattern to different physical conditions – such as walking with a heavy backpack

Question 31

What controls voluntary gait modification

Answer 31

Supraspinal and cerebellar inputs are involved in gait initiation, voluntary gait modification, climbing stairs, walking over obstacles etc

Question 32

Treadmill Training Cat Study- bodyweight support

Answer 32

Barbeau and Rosignol
Cats subject to transection of the cord at a thoracic level

Trained for 30-60 min /day to walk on a treadmill with their hindlimbs while their forelimbs remained on a platform.

Early in training coordinated locomotion occurred only when the experimenter provided weight support for the hindlimbs

And a strong sensory input - stimulation of the tail – pinching of the tail gives an extensor response
Coordinated locomotion developed and improved
over days and weeks.

Animals gradually walked faster, bear more weight, with longer steps and for longer periods of time.

They eventually required little or no weight support or sensory stimulation to do this.
Locomotion was much better in cats exposed to this
treadmill training than in cats that received only normal
nursing care after injury.

Although untrained cats regained some locomotor ability they were clearly inferior to the trained cats.

Question 33

Cat Treadmill experiment- mechanism for walking response

Answer 33

They generated a hindlimb stepping response – even in the absence of supraspinal control

Treadmill forces hip extension – flexor burst and helps with swing initiation

Extensor load relayed to the Golgi Tendon Organs

Sensory input of hip extension position and load may be facilitating the network of spinal interneurons - often referred to as the CPG

Reinforcing the spinal flexion/extension basic stepping sequence

Question 34

Standing Cat study

Answer 34

Hodgson
Cats were trained to either stand on hind limb or walk on hind limb.
Each group learned their task but could not perform the non trained alternate task.
Task Specificity!

Question 35

SCI Goals

Answer 35

Goals –strengthen muscles that remain under voluntary control, compensate for paresis or paralysis using braces and assistive devices

Question 36

SCI Paradigm shift

Answer 36

Paradigm shift – from compensation for deficits to rehabilitation for walking recovery

Question 37

SCI treadmill training

Answer 37

Dobkin
treadmill training vs conventional rehab
those that received treadmill training showed increased walking ability
improvement has been reported in patients recently injured and in those injured a while ago. improvement persisted beyond training

Question 38

LEAPS trial

Answer 38

Body-weight-supported treadmill rehabilitation after stroke.
Compared dif types of tx in pt post stroke
1 type tx- bodywightsupported treadmil straining
Inteverion 2- intesntive trainign by PT
3- training low intensity
Locomotor training, including the use of body-weight support in stepping on a treadmill,
was not shown to be superior to progressive exercise at home managed by a physical therapist.

Question 39

ICARE

Answer 39

3 groups:
-Accelerated Skill
Acquisition Program
(structured task oriented
UE training)
-Dose Equivalent OT
-Usual Care OT
did not find any difference
b/w skill acquisition and Dose Equiv
groups
both groups had adaptive
& progressive interventions
-did not find any difference
b/w experimental groups
and usual care (control)
group
it’s not just the type of
intervention that causes a
change
-timing & duration of the
intervention affect
outcomes
-recovery based upon
intense practice for a
specific task
-development of
technology to train
activity-based locomotion
& UE function
-interventions must be
progressive & adaptive