Injury and Recovery in the CNS

Question 1

What is cerebral palsy?
What do the motor disorders of CP also inc?

Answer 1

Movement and posture disorders that occurred in the developing brain.
The motor disorders of CP also inc: disturbances of sensation, perception, cognition, communication, behaviour, epilepsy, and secondary musculoskeletal problems.

Question 2

what is stroke?
can vascular occlusions reopen?

Answer 2

6-8 mins of blood supply interruption (ischaemia) to cause neuronal death (infarction).
Most cerebral vascular occlusions reopen spontaneously within 24 hours, but for the neurones this is too late.

Question 3

Describe hypoxic brain injury and where it mostly affects

Answer 3

Reduction of whole brain oxygenation
Preferentially affects the most metabolically active parts of the brain

• Grey matter
• Cerebral cortex
• Basal ganglia

Question 4

Describe MS

? disease where ? are damaged
The nervous system can ?
Depending on where the nerve cells are this results in ?

Answer 4

Multiple sclerosis: demyelinating disease where insulating covers of nerve cells in brain+ SC are damaged
The nervous system can no longer transmit signals. Depending on where the nerve cells are this results in physical,mental, sometimes psych problems

inflammation -> demyelination -> neuronal dysfunction

Question 5

How is MS typically diagnosed?
What can you see on an MRI?

Answer 5

Diagnosed based on the presenting symptoms
CSF is tested for oligoclonal bands of IgG on electrophoresis, which are inflammation markers

On MRI scan you can see these areas of high signal scattered through the brain, or they can even present as bright areas on spinal cord lesions

Question 6

What can tumours within the vertebrae cause?

Answer 6

Question 7

How do infections like these affect the brain?

Answer 7

Question 8

Describe the fate of injured neurones depending on the injury type

Answer 8

If a neuron has axotomy (axon been cut) and target loss= loss of trophic factors and support

Denervation (neurons which lose their normal input)= change in synaptic balance.
Consequences of denervation can be subtle e.g. transmitter hypersensitivities in spinal cord injury causing spasticity
OR cause transneuronal atrophy or degeneration, e.g of visual and auditory systems

Question 9

Denervation of neurons in the visual and auditory systems can lead to what?

Answer 9

loss of trophic factors, loss of synaptic input to the LGN.
Destruction of the projections from the eye results in atrophy of neurons in the LGN
And interruptions of the 8th (vestibulocochlear) nerve leads to atrophy of neurons in the cochlear nucleus.

Question 10

What is regeneration after neuronal injury?
Where does it occur and what is needed for it?

Answer 10

Regeneration: Regrowth of severed axons
Occurs in non-mammalian vertebrates
Occurs in mammals’ PNS

Myelin is critical: provides a guide for the end of a severed neuron to grow through
Extending axon is guided to its destination like during development

Question 11

What is glial scarring?
What are the benefits and detriments of it?

Answer 11

Glial scarring (gliosis): proliferation of astrocytes and microglia after CNS injury as part of healing
Benefits:
Regenerates a tissue barrier after BBB compromise
Promotes revascularisation of injured brain.
Detriments
Astrocytes secrete neuro-developmental inhibitors that prevent axon regrowth

Question 12

Describe neurogenesis in adults

Answer 12

The adult mammalian brain produces relatively few new neurons
BUT: evidence for significant neurogenesis in:
hippocampus (dentate gyrus)
near the lateral ventricles (subventricular zone), supplying the olfactory bulb
Both important for memory, so perhaps memory can “grow”.

Question 13

How do you fix the brain if you can’t grow new neurons? (3 ways)

Answer 13

1)Compensation: one brain area take over the functions damaged in another area. Simplest neural recovery

2)Presynaptic neurons sprout more terminals to
form extra synapses w targets. Add more receptor cells

3)Reorganisation: more dramatic, can involve major brain areas.

Question 14

Relate Neurorehabilitation with the CNS

Answer 14

The CNS continuously remodels its neural circuitry throughout life to encode new experiences.
Neurorehabilitation capitalises on the way the brain normally learns to relearn lost function.
This approach of learning promotes adaptive neural plasticity

Question 15

So does our brain have Specific areas for specific functions?
What can this be changed by?

Answer 15

Yes and NO! Flexible and subject to neural plasticity- can be changed by:
Peripheral and central injury
Electrical stimulation
Learning and experience

Question 16

What are some restorative movement techniques- ie to encourage plasticity?
Why is therapy important?

Answer 16

Some specific techniques might be effective in brain pathway transmission, reorganisation and performance
Based on this, therapy might need to be task specific to enhance the specific function
Intensity and timing might be important
Therapy is important bc drugs have not been successful in restoration

Question 17

What are the 5 effects of stem cell transplantation?

Answer 17

Intrinsically neuroprotective
Anti-inflammatory
Anti-apoptotic
Delivery of trophic factors that are missing
Overcome natural inhibitors in the CNS

Question 18

What is TMS?

Answer 18

Transcranial magnetic stimulation: noninvasive, uses magnetic fields to stimulate nerve cells in the brain to improve depression.

A coil is applied to the head above the left prefrontal cortex (regulates mood). These magnetic fields do not directly affect the whole brain; they reach ~2-3cm into the brain beneath the treatment coil. The electrical currents from the magnet release neurotransmitters.