PBL - Parkinson's Disease

Question 1

Describe declarative memory

Answer 1

Factual information
Life events
Available to the consciousness
Easily formed and forgotten

Question 2

Describe non-declarative memory.

Answer 2

Procedural memory
Motor skills
Not available to the consciousness
Less easily formed and forgotten

Question 3

Describe ballistic movements

Answer 3

Movement based on pre-programmed instructions
Rapid, but at the expense of accuracy
- can’t accommodate unexpected changes

Question 4

Describe visual feedback movements.

Answer 4

Motor command continually updated according to sensory feedback (e.g. Visual)
Highly accurate - can be modified in progress
Slow

Question 5

Out of ballistic and visual feedback movements, which is used more often in the body?

Answer 5

A mixture of both

Question 6

What does stimulation of the primary motor cortex do?

Answer 6

Elicits muscle twitches/movements depending on the amount of stimulation

Question 7

What is the somatotrophic map?

Answer 7

Certain areas of the motor cortex specifically control certain areas of the body

Question 8

How is the somatotrophic map distorted?

Answer 8

Face, hands and digits receive larger representation in the primary motor cortex
- due to more through the required for fine control

Question 9

If there is a stroke or heamatoma in or near the primary motor cortex, what (motor) effect will be had on the body?

Answer 9

Paralysis and loss of sensation on the side contralateral to the pathology

Question 10

What sensory information is crucial for co-ordinated movements?

Answer 10

Proprioception - feedback from peripheral sensory reports on the positions and movements of limbs
Vision - eyes, visual system, visual cortex
Vestibular - feed back from organ of balance

Question 11

What are the main non-cortical structures required for movement?

Answer 11

Basal ganglia

Cerebellum

Question 12

What is the input and output from the basal ganglia?

Answer 12

Input - prefrontal motor cortex (intended movement)

Output - premotor area of the thalamus

Question 13

What are the functions of the basal ganglia?

Answer 13

Initiation of movement - puts motor plan into action

Planing of complex voluntary movement

Question 14

What is the input and output for the cerebellum?

Answer 14

Input - sensory cortex

Output - primary motor cortex (via the thalamus)

Question 15

What are the functions of the cerebellum?

Answer 15

Co-ordination and smooth execution of movements
Motor learning
Error detection

Question 16

What does damage to the cerebellum do?

Answer 16

Causes cerebellar ataxia - poor co-ordination

Question 17

What are the lateral descending motor pathways?

Answer 17

Corticospinal and rubrospinal

- pyramidal neurons in primary motor cortex project to the spinal cord (corticospinal) and red nucleus (rubrospinal)

Question 18

What are the functions of the lateral motor pathways?

Answer 18

Control of voluntary movements

- e.g. Fine control of the hand by distal muscles

Question 19

What is the function of the vestibulospinal tract?

Answer 19

Balance and posture

Question 20

What is the function of the reticulospinal tract?

Answer 20

Medial path facilitates voluntary movement and increased muscle tone
Lateral path inhibits voluntary movements and decreases muscle tone

Question 21

What is the function of the tectospinal tract?

Answer 21

Co-ordinates movements in the head in relation of visual stimuli

Question 22

What evidence is there for function of the supplementary motor cortex?

Answer 22

Imaging studies show your primary motor cortex, premotor cortex and supplementary motor cortex are involved involved in moving a finger.
However, only the SMA is involved in THINKING about moving the finger (but not actually moving it)

Question 23

What are the symptoms of Parkinson’s disease?

Answer 23

Tremor
Bradykinesia
Shuffling gait 
Rigidity 
Progression to general cognitive decline

Question 24

What are the two treatments for Parkinson’s?

Answer 24

Levodopa - and cabidopa to prevent peripheral breakdown

Deep brain stimulation

Question 25

What is Huntington’s disease?

Answer 25

Suppression of activity in the basal ganglia

Question 26

What are the symptoms of Huntington’s disease.

Answer 26

Choreas
Difficulty speaking and swallowing
General cognitive decline

Question 27

How do intrinsic circuits of the spinal cord produce the rhythmic motorneuron activity which drives stepping?

Answer 27

Alternating activity in flexor and extensor muscles co-ordinated across two limbs
Two sets of pattern generating neurons project to flexor and extensor motorneuron pools respectively
Reciprocal inhibitory connections between the two sets of pattern generating neurons help to co-ordinate their activity
- alternating excitement of flexors and extensors

Question 28

Motorneuron pools of each muscle form columns in the ventral horn, what are they called?

Answer 28

Motornuclei

Question 29

What is the most important mechanism for grading motor force?

Answer 29

Recruitment of motor neurons

Question 30

Describe the effect of action potential frequency in motor axons on muscle fibre contraction.

Answer 30

The more action potentials, the stronger the muscle contraction
No rest period means each action potential increases contraction form an already elevated level