Motor areas

Question 1

How were the cortical areas identified initially?

Answer 1

They are anatomically distinct

Question 2

What are the primary motor areas?

Answer 2

M1/motor cortex/area 4

Question 3

What are the large cells in layer V of the motor cortex?

Answer 3

Cortical spinal cells, which are distinguishing features of the motor cortex and are common in all animals

Question 4

Why is the primary motor area regarded so?

Answer 4

Is the area where movement can be elicited with the lowest threshold of stimulation

Question 5

How can you map somatotophy?

Answer 5

Electrodes; transcranial magnetic stimulation; neuroimaging

Question 6

Is the somatotophy in all humans the same?

Answer 6

No, has same general pattern but each person has variations

Question 7

What is the relationship between the motor cortex and movement?

Answer 7

Very close; fire around 5-100ms before movement

Question 8

What does the motor cortex control in movement?

Answer 8

Force, direction, extent, speed

Question 9

What are the non-primary motor areas?

Answer 9

Pre-motor cortex/lateral area 6; supplementary motor cortex/medial area 6; cingulate motor areas/areas 23 and 24

Question 10

What do the PMA and SMA control?

Answer 10

Complex patterns and sequences of movements; movement selection and preparation; target encoding

Question 11

What are the main inputs for the PMA and SMA?

Answer 11

From other motor areas

Question 12

What is the difference in stimulation of PMA/SMA and M1?

Answer 12

Need higher thresholds of stimulation to PMA/SMA to produce movement

Question 13

What is the difference in output of SMA and M1?

Answer 13

Output from SMA to weaker neurones markedly weaker than M1

Question 14

What cortex has longest latency?

Answer 14

PMA/SMA

Question 15

How much larger is PMA and SMA than M1?

Answer 15

6 times larger

Question 16

What is the focus of the pre-motor cortex?

Answer 16

Set-related neuronal activity; movement planning

Question 17

What is the focus of the supplementary motor cortex?

Answer 17

Bimanual tasks

Question 18

What occurs when cortical damage occurs?

Answer 18

Loss of voluntary movements; weakness; paralysis

Question 19

What does the basal ganglia control?

Answer 19

Movement regulation; skill learning; habit formation; reward systems

Question 20

How do the pathways of the basal ganglia work together?

Answer 20

Both start at cortex; normally balanced

Question 21

What are the differences between the two pathways?

Answer 21

Direct has an excitatory effect on cortex, indirect has an inhibitory effect on cortex; direct is pro-movement, indirect is anti-movement

Question 22

What happens when someone suffers from hyperkinetic disorders?

Answer 22

Shifted towards direct pathway; unwanted movements initiated involuntarily; e.g. Huntington’s

Question 23

What happens when someone suffers from hypokinetic disorders?

Answer 23

Shifted towards indirect pathway; cannot initiate movement; e.g. Parkinson’s

Question 24

What is the ratio of input:output of cerebellum?

Answer 24

40:1

Question 25

What is the structure of the cerebellum?

Answer 25

Crystalline, simple, three layers, 5 kinds of cells

Question 26

What are the 5 kinds of cells in the cerebellum?

Answer 26

Inhibitory stellate
Basket
Purkinje
Golgi
Excitatory granule

Question 27

What are the inputs to the cerebellum?

Answer 27

Only has 2; one is inferior cerebellar peduncle

Question 28

What are the outputs of the cerebellum?

Answer 28

Mainly motor; superior cerebellar peduncle to motor cortex and red nuclei; inferior cerebellar peduncle to vestibular nuclei

Question 29

What are the motor deficits caused by cerebellum damage?

Answer 29

Delayed movement; range of movement errors (e.g. touching nose); patterned movement errors