L16: Motor Cortices - A

Question 1

Which two structures are important for external cues?

Which structures is important for internal cues?

Answer 1

External
- PMA/C

Internal
-SMA

Question 2

____ program is considered to be the “how” of movements while the ____ program is considered to be the “when” of movements

Answer 2

Praxic Programs =
how

Intentional Programs = when

Question 3

True or False: The Praxic Programs are associated with the basal ganglia while the Intentional Programs are associated with the cerebral cortical areas

Answer 3

False - Praxi Programs are associated with Cerebral Cortical areas;

Intentional Programs are associated with Basal Ganglia

Question 4

True or False: Midcourse corrections of movements are possible and involve cerebellar circuitry

Answer 4

True

Question 5

_____: Neurons that innervate skeletal muscles (form motor end plates)
A. Upper motor neurons
B. Lower motor neurons

Answer 5

B. Lower motor neurons

Question 6

Neurons in Layer V of ___ give rise to axons that contribute to the CST
A. SMA
B. PMA
C. PMC
D. M-I
E. FDF

Answer 6

D. M-I

Question 7

True or False: Hands and face (areas important for precision and fine control) have disproportionately large representation in motor map

Answer 7

True

Question 8

Where do neurons in Layer V of M-I–which give rise to axons that contribute to the CST–terminate?

Answer 8

Ventral horn of all levels of the spinal cord

Question 9

Main function of the CST?

Answer 9

Activate neurons in ventral horn (innervates distal musculature)

Question 10

Which of the following activates fine, distal movements around a SINGLE joint?
A. SMA
B. PMA
C. PMC
D. M-I
E. FDF

Answer 10

D. M-I

Question 11

True or False: Electrical threshold for eliciting movement is lower in M-I than in any other part of the cerebral cortex

Answer 11

True

Question 12

M-I is kept informed about position of limb and speed of movement through which two sensory input?

Answer 12

1) Thalamus –thalamocortical connections

2) S-I – corticocortical connections

Question 13

True or False: Although the PMC is x6 larger than M-I, it only contributes a small portion to the CST

Answer 13

True

Question 14

Which of the following structures plays a role in planning and setting the stage for a motor task?
A. SMA
B. PMA
C. PMC
D. M-I
E. FDF

Answer 14

C. PMC

Question 15

True or False: Activity in PMC is increased with initiation of a motor task

Answer 15

False - activity in PMC is DECREASED with initiation of a motor task

Question 16

Transformation and integration of sensory information into motor programs is an important function of both the ___ and the ____

Answer 16

PMC and PMA

Question 17

Coordinated movement of the limbs (contraction of muscles at more than 1 joint) can be elicited by stimulating the ____
A. PMC
B. PMA
C. M-I
C. SMA

Answer 17

A. PMC

Question 18

True or False: Compared to the M-I, movements by the PMC are faster than those seen after M-I stimulation and more likely to involves smaller groups of muscles

Answer 18

False - compared to M-I, movements by the PMC are SLOWER than those seen after M-I stimulation and more likely to involves LARGER groups of muscles

Question 19

True or False: Both the PMC and SMA contain motor homunculus, but one that is not as precise as M-I

Answer 19

True

Question 20

True or False: Stimulation of SMA produces complex motor movements and coordinates movement on both sides of the body

Answer 20

True

Question 21

True or False: Threshold for movements is higher in the SMA compared to the M-I

Answer 21

True

Question 22

Action of proximal m occurs directly via corticospinal projections from the ____ to the ventral horn of the spinal cord
A. M-I
B. SMA
C. PMC
D. PMA

Answer 22

B. SMA

Question 23

Action of distal muscles occurs indirectly via connections from the __ to ___

Answer 23

SMA to M-I

Question 24

True or False: SMA neurons appear to inhibit M-I neurons and RETAIN learned motor programs

Answer 24

False - while the SMA does appear to RETAIN learned motor programs, SMA neurons appear to excite M-I neurons

Question 25

What is the main input to the PMA?

Answer 25

Primary somatosensory (S-I) cortex

Question 26

In which area is neuronal activity modulated by states of attention?

Answer 26

PMA

Question 27

PMA can be driven by sensory stimuli, but only in context of specific behavioral responses – ___ ____ activities

Answer 27

goal-oriented

Question 28

Which of the following is involved in initiation of rapid horizontal eye movements (saccades)?

Answer 28

Frontal Eye Fields

Question 29

True or False: Stimulation of the S-I (Primary Somatosensory cortex) and the PFC elicits motor movements

Answer 29

False - does NOT elicit movement

Question 30

The S-I contributes fibers to the CST, which terminate in the ____ ____ of the SC and, therefore, are in a position to modulate incoming sensory info before it reaches consciousness

Answer 30

dorsal horn

Question 31

Lesions of S-I may cause what appear to be motor deficits – but deficits are not due to motor dysfunction. They are actually caused…?

Answer 31

Lack of sensory information reaching motor areas

Question 32

One has a lesion in PFC. What symptoms/behaviors are to be expected?

Answer 32

1) More distracted
2) Lack of motivation

Answer 33