1b Cerebral Cortex Flashcards
What is MS?
An autoimmune disorder which results in the loss of myelin from the neurones of the central nervous system ie the brain and spinal cord
What are some of the main symptoms of MS?
Blurred vision, fatigue, difficulty walking, numbness or tingling (paraesthesia), spasms
What is the M wave?
Activation of the motor axons that result in a muscle contraction or twitch. Fast response ~8ms
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. Reflex action. ~30ms
What is antidromical movement of impulses?
When the impulse goes in the wrong direction - travels along the motor neurone to the spinal cord
What causes antidromic impulses?
Not large enough electrical stimuli
What is the F wave?
Motor and Motor - small impulse is seen as the impulse goes in the wrong direction ~30ms
What is meant by orthodromic?
An electrical stimuli which is travelling in the normal direction of the nerve fibre
Describe the movement of an antidromic impulse?
Starts at the muscle, goes to the spinal cord, turns around and goes back to the muscle
How long does it take for an antidromic impulse to turn around?
1 second
Which wave are both motor and sensory stimulated?
H wave
What is transcranial magnetic stimulation
Cortical motor stimulation
How does cortical brain stimulation work?
The activation of the upper motor neurones cause APs to travel along the entire motor pathway to cause muscle contraction = seen as a twitch. Response is known as motor evoked potential.
What is the Total motor conduction time?
The time from brain to muscle - MEP latency ~19.5ms in hand and 26.5 in leg
What is the peripheral motor conduction time?
The time from the spinal cord to the muscle ~13.6ms in hand and 12.7 in leg
