Motor Systems 2 - Ebner

Question 1

What kinds of deficits do you see in pyramidal (corticospinal) tract lesions?

Answer 1

1. Deficits in control of hand
   - loss of opposition of thumb and index finger - instead use hand like cup
   - loss of independent extension of one digit
   - cupping and scooping movements

HOWEVER
2. Reaching, locomotion, and other movements intact

Question 2

What are the deficits that you see in lesions of the primary motor cortex?
Just outline briefly. Will ask details later.

Answer 2

1 - Upper motor neuron syndrome
2 - Deficits in fine motor control of hand, foot, mouth, and tongue
3 - Corticobulbar signs (Lower face is biggie)

Question 3

What are the signs that accompany upper motor neuron syndrome?

Answer 3

Paresis
Increased extensor tone
Increased stretch reflexes
Babinski Sign

Question 4

What are the classic corticobulbar signs accompanying lesions of the primary motor cortex?

Answer 4

contralateral lower facial weakness

Slight:
ipsilateral weak trapezius/Sternocleidomastoid
Contralateral weak tongue

Question 5

What is the main responsibility of the premotor cortex?

Answer 5

1. Involved with sensorimotor transformations (i.e., transforming a sensory cue into a
motor action)
2. Involves planning and learning
3. Dorsal premotor area for arm movement
4. Ventral premotor for hand movemen

Question 6

Premotor Area:

Afferent projections?

Answer 6

1. Prefrontal cortex
2. Supplementary motor area
3. Posterior parietal (Areas 5 and 7) Visual/Space
4. Cingulate motor area
5. Cerebellum and basal ganglia via
   thalamus

Question 7

Premotor Area:

Efferent projections?

Answer 7

1. Area 4
2. Supplementary motor area 3. Posterior parietal
3. Prefrontal areas
4. Basal ganglia
5. Brainstem, red nucleus
6. Corticospinal

Question 8

Say again:

What is difference in function between the ventral vs dorsal premotor cortex?

Answer 8

Dorsal premotor area for arm movement

Ventral premotor for hand movement

Question 9

Explain mirror neurons and their possible practical functions?

Answer 9

They are neurons which discharge BOTH when an individual performs a task AND when they watch another individual perform the exact same task

• Possible function:
  Imitation? Understanding? Intention?

Question 10

What kinds of deficits do you get in premotor lesions?

Answer 10

Inability to reach around barriers
Can’t execute complex motor plans requiring visuomotor transformation
Patients don’t steer arm accurately
Can’t learn new sensory-motor associations

Question 11

Supplementary Motor Area functions?

Answer 11

Internal generation of movements

Sequences of learned movements

Question 12

What are the afferent projections of the SMA?

Answer 12

1. Area 4
2. Prefrontal cortex/pre-SMA 3. Posterior parietal
3. Basal ganglia
4. Cerebellum

Question 13

What are the efferent projections of the SMA?

Answer 13

1. Area 4
2. Striatum
3. Brainstem
4. Corticospinal

Question 14

Allright just remind me the overall functional difference between the PMA and the SMA?

Answer 14

PMA = externally driven movements
SMA = Internally driven movements

Question 15

What kind of deficits do SMA lesions create in patients?

Answer 15

Deficits in internally guided and sequences of movements

1. Patients become stimulus bound, show utilization behaviors (put on these glasses)
2. Patient sometimes cannot recognize hand
   (Alien hand syndrome)
3. Trouble executing learned sequences

Question 16

As an individual becomes highly skilled at particular tasks, their brain activity will shift from_____ to ______

Answer 16

from high SMA activity
to
high motor cortex activity