Motor Control II

Question 1

Brainstem function

Answer 1

-initiation of locomotion
-maintain balance and posture (vestibular nuclei)
-changes in direction
-coordination of gait

Question 2

Cerebral cortex (motor cortex) control of locomotion

Answer 2

-voluntary movements
-visually guided movements
-navigate uneven terrain, obstacles, or any voluntary adjustments
-memory of stepping over objects can be stored in temporal lobe (short term memory)
**UMNs of cortex control the activity of the brainstem nuclei

Question 3

Levels of motor control in CNS

Answer 3

1.Spinal cord (LMNs)
2. brainstem (UMNs from nuclei)
3.Cerebral cortex/motor cortex (UMNs)
>limited direct connection with spinal cord in domestic species because ends after C1-C5 cervical region. No connection with limbs.

Question 4

Structures involved in moderation of motor movements

Answer 4

-Basal nuclei
-Cerebellum
**Don’t have any UMNs or LMNs so do not control movements directly, just modulate motor movements

Question 5

Basal nuclei

Answer 5

-a group of subcortical nuclei in the forebrain and midbrain
- initiate, sustain, and terminate motor movements (PLANNED movements) but not to do with actually responding to stimuli)
>decision making
>filter what appropriate and inappropriate movements are
>postural control

Question 6

Cerebellum

Answer 6

-important for moderation and control of motor movements
-determines appropriate vs inappropriate movements
>ex. Animal reaching and locating object correctly

Question 7

Where does the basal nuclei receive input?

Answer 7

-Receives input from cerebral cortex, passes on to basal nuclei, information is passed on to thalamus, and then back to cerebral cortex to initiate movement

Question 8

Where does cerebellum receive input from?

Answer 8

-received proprioceptive inputs
-these proprioceptive inputs can also be passed directly to thalamus and then back to the cerebral cortex OR cerebellum receives information and then passes it to thalamus then cerebral cortex, or directly to the brainstem/nuclei

Question 9

Lesion in basal nuclei in domestic animals

Answer 9

-clinically not common in domestic species; common in primates
-Exception is horses: Yellow Star Thistle
>toxicity from eating the plant results in damage to basal nuclei affecting their ability to coordinate movements to prehend food

Question 10

Results of Lesions of basal nuclei

Answer 10

1.inability to initiate planned movements
2.involuntary abnormal motor movements
3. Sequencing difficulties

Question 11

Human diseases linked with basal nuclei lesion

Answer 11

-Parkinson’s: hard to initiate movements
-Huntington’s: hard to coordinate=spastic movements
-Tourettes: hard to coordinate=spastic movements or vocalizations
-Obsessive compulsive disorder