motor systems 2

Question 1

Where does motor command originate

Answer 1

In the moror cortex puramidal cells

Question 2

Features of the descending projections from cortical motor areas

Answer 2

• cell body are located in grey matter of cortex
• pyramidal cell axon can project directly/indirectly to spinal cord + onto lower brainstem motor neurons
• cortical projections innervate contralateral motor units

Question 3

projections from the motor cortex

Answer 3

• motor command originates in motor cortex pyramidal cells (upper M.N)
• descending tract = pyramidal tract

Question 4

Basal ganglia

Answer 4

• group of nuclei lying deep within cerebral hemispheres

Question 5

What are the five principle nuclei

Answer 5

1. ) Substantial nigra: pars compacts + pars reticulata
2. ) Caudate + putamen (together = striatum)
3. ) Globus pallidus
4. ) Subthalmic nucleus

Question 6

Diseases caused by basal ganglia disruption

Answer 6

1. ) Parkinson’s
2. ) Huntington’s
3. ) Tourette’s
4. ) Tardive Dyskinesia
5. ) Hemiballismus

Question 7

Selection problem

Answer 7

There are multiple commands but it can’t do more than one thing at a time

Question 8

How to decided what wins control of motor resource?

Answer 8

Centralised selection

Question 9

What is the hypothesis

Answer 9

Basal Ganglia acts as a centralised action selector

Question 10

Cerebellum

Answer 10

• It modulates activity of upper motor neurons

Question 11

Features of the cerebellum

Answer 11

• when damaged: movements become jerky/erratic + poorly co-ordinated
• get an intention tremor or dysarthria

Question 12

Cellular structure

Answer 12

- intricate folded structure to maximise 
Features:
1.) Foliae
2.) Pia mater
3.) Molecular layer
4.) Purkinje cell layer
5.) Granule layer
6.) White matter

Question 13

Inputs to the cerebellum

Answer 13

1. ) Spinal cord
2. ) Vestibular system
3. ) Cerebral cortex + pons

Question 14

Outputs to cerebellum

Answer 14

Thalmaus -> motor cortex

Question 15

Inputs and outputs

Answer 15

1. ) Cortical
2. ) Spinal
3. ) Vestbular

Question 16

Cerebellar function

Answer 16

• it knows what the current motor comman is-> it knows what actual body position and movement-> it projects back to motor cortex-> computes motor error + adjusts cortical motor commands accordingly