Nervous system: Parkinson's disease

Question 1

Label the diagram

Answer 1

Question 2

What is the condition called when there is a lesion near the upper regions of the corticospinal tract?

Answer 2

Spastic paralysis

Question 3

What are the symptoms of a spastic paralysis?

Answer 3

They would be stiff and an over exaggerated response to a stimulus

Question 4

What causes the symptoms of a spastic paralysis?

Answer 4

Because the corticospinal tract is damaged and not transmitting neural signals from the upper motor neurons to the spinal cord, the lower motor is not controlled and lower motor neurons tend to fire neural signals that are too strong resulting in exaggerated responses in muscles

Question 5

What is the condition called when there is a lesion in the spinal cord?

Answer 5

Flaccid paralysis

Question 6

What are the symptoms of a flaccid paralysis?

Answer 6

There is no muscle activation (i.e. limp limbs)

Question 7

What causes the symptoms of a flaccid paralysis?

Answer 7

When a lesion occurs in the spinal cord it causes all the motor neuron from the lower motor neurons up to be unable to transmit signals to the muscle resulting in little/no stimulation of the muscle resulting in no muscle tone

Question 8

What is the main issue associated with Parkinson’s disease?

Answer 8

Initiating motor neurons

Question 9

What is bradykinesia?

Answer 9

A reduced ability to move

Question 10

What is the nick name for a condition for Parkinson’s patients that involves facial muscles?

Answer 10

Wooden face

Question 11

What is wooden face?

Answer 11

It is the condition where parkinson’s patients are unable to create facial expressions that match their actual feelings

Question 12

Why do Parkinson’s patients get wooden face?

Answer 12

The face has a homunculus representation of about half the neurons of the primary motor cortex and due to the inability to initiate muscles quickly, it is difficult for the to change facial emotions quickly

Question 13

What kind of neurotransmitter is the striatum activated by?

Answer 13

Dopamine

Question 14

The dopamine activated cells in the striatum are kept in what kind of state?

Answer 14

They are always kept in a state where they are ready to produce an action potential for the slightest change in neurotransmitter

Question 15

Why are the striatum cells kept in a constant state of being ready to fire?

Answer 15

So that if there is even the slightest change in the neural input they will produce an action potential

Question 16

What happens to the striatum’s ability to produce an action potential if the dopaminergic pathway is damaged? Why?

Answer 16

It is greatly reduced

The striatum cells are not kept in a state where they can fire at the slightest change of neurotransmitter

Question 17

How does a damage dopaminergic pathway impact motor planning? Why?

Answer 17

It reduces it’s ability to contribute to motor planning, i.e. difficulties in initiating movement, tremors, decrease movement refining

The striatum is less able to produce an action potential so it can’t drive the basal ganglia system

Question 18

What parts of the brain are feed information into the lower part of the striatum? What kind of actions are associated with this part of the striatum?

Answer 18

The frontal parts of the brain

Mood and impulse

Question 19

When the dopaminergic pathway is damaged, what are the impacts?

Answer 19

Loss of fine movement, initiating movement and loss of mood and impulse

Question 20

What condition is caused by the damage of the dopaminergic pathway?

Answer 20

Hypokinesis

Question 21

Explain the pathway for hypokinesis

Answer 21

Dopaminergic pathway is damaged which means that the GABA pathways (which are inhibitory) are not controlled by the striatum resulting in their overstimulation. This overstimulation of the inhibitory pathway at the thalamus causes the glutamatergic pathway from the thalamus to eh cerebral cortex to become inhibited resulting in under stimulation of the cerebral cortex = hypokinesis

Question 22

What is hypokinesis?

Answer 22

A lack of planning of movements

Question 23

How can you treat Parkinson’s disease?

Answer 23

Levo-dopa

Question 24

What is levo-dopa?

Answer 24

The precursor of dopamine

Question 25

What does levo-dopa do?

Answer 25

It is a substitute for dopamine which allows the striatum to function normally

Question 26

Is levo-dopa a full proof treatment for parkinson’s? Why/why not?

Answer 26

No

It only works for ~8years before either the disease gets worse or the body develops tolerance for levo-dopa which means treatment no longer effective

Question 27

What does extremes of dopamine do to a person’s movement and behaviour?

Answer 27

Very low = Catatonia, stiffness/rigidity

Very high = Wild movements, psychosis and depression

Question 28

What is very low dopamine associated with?

Answer 28

Parkinson’s disease

Question 29

What is very high dopamine associated with?

Answer 29

Schizophrenia

Question 30

What is a difficultly in treating Parkinson’s disease with levo-dopa?

Answer 30

It causes very large fluctuations in dopamine in your system which results in large mood and behaviour changes throughout the day