1b Cerebral Cortex Flashcards

1
Q

What is MS?

A

An autoimmune disorder which results in the loss of myelin from the neurones of the central nervous system ie the brain and spinal cord

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2
Q

What are some of the main symptoms of MS?

A

Blurred vision, fatigue, difficulty walking, numbness or tingling, paraesthesia, spasms

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3
Q

What is the M wave?

A

Activation of the motor axons that result in a muscle contraction or twitch

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4
Q

What is a H reflex - When the impulse travels along the sensory to the spinal cord, and then causes the lower motor neurones to become activated, resulting in a twitch

A
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5
Q

What is antidromical movement of impulses?

A

When the impulse goes in the wrong direction - travels along the motor neurone to the spinal cord

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6
Q

What causes antidromic impulses?

A

An large enough electrical stimuli

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7
Q

What is the F wave?

A

Motor and Motor - small impulse is seen as the impulse goes in the wrong direction

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8
Q

What is meant by orthodromic?

A

An electrical stimuli which is travelling in the normal direction of the nerve fibre

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9
Q

Describe the movement of an antidromic impulse?

A

Starts at the muscle, goes to the spinal cord, turns around and goes back to the muscle

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10
Q

How long does it take for an antidromic impulse to turn around?

A

1 second

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11
Q

Which wave are both motor and sensory stimulated?

A

H wave

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12
Q

What is transcranial magnetic stimulation

A

Cortical motor stimulation

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13
Q

How does cortical brain stimulation?

A

The activation of the upper motor neurones cause APs to travel along the entire motor pathway to cause muscle contraction = seen as a twitch

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14
Q

What is the Total motor conduction time?

A

The time from brain to muscle

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15
Q

What is the peripheral motor conduction time?

A

The time from the spinal cord to the muscle

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16
Q

How is the PMCT calculated?

A

(M Latency + F Latency) - 1 / 2

17
Q

Why minus one in the PMCT calculation?

A

The minus one accounts for the time taken for the impulse to turn around

18
Q

How is the central motor conduction time calculated?

A

CMCT = TMCT - PMCT

19
Q

What is the effect of MS on the brain as seen in brain stimulation?

A

Longer than usual MEP Latency

20
Q

What is seen during peripheral nerve stimulation for a patient with MS?

A

Normal F wave latency, no issue with lower motor neurones

21
Q

How is it established that the problem is in the CNS if the patient has MS?

A

TMCT is delayed
PMCT = normal
Therefore problem lies in the CNS

22
Q

The doctor sees the EEG wave at 30ms latency. What 2 waves could this be?

A

H reflex or F wave

23
Q

What causes the blurred vision in MS?

A

Optic neuritis

24
Q

Name the EEG waves caused by orthodromic activation.

A

M wave or H reflex