8.1: Motor Cortex and Cerebellum

Question 1

Name the three motor cortical areas and their responsibilities

Answer 1

1. Limbic system: origin of desire to move
2. Prefrontal/premotor and supplementary motor cortex: attention, understanding and planning of movement
3. Primary motor cortex: direct signals to spinal cord

Question 2

What are the two sub-cortical areas involved in the motor system and what are they responsible for?

Answer 2

Basal ganglia - fine tune

Cerebellum - coordination

Question 3

What are the basal ganglia and what is their role?

Answer 3

Multiple deep, subcortical nuclei that influence movements such as smooth motor movements, amplitude and velocities, posture control and resting muscle tone by regulating the activity of UMNs

Question 4

Which structures are involved in the basal ganglia?

Answer 4

Caudate, putamen, globus pallidus, substantia nigra (midbrain), subthalamic nuclei (ventral thalamus)

*include photo

Question 5

What happens if there is a defect to the basal ganglia?

Answer 5

Inability to control movement, problems switching between commands and initiating and terminating movements

Question 6

Where do the basal ganglia reside/project? Describe the pathway of their signals

Answer 6

Project from the cerebral cortex via the internal capsule to the input region known as corpus striatum; composed of the caudate and putamen

Signals project from the input region to other nuclei and form discrete loops/circuits which feedback to the cerebral cortex via the thalamus. Circuits can be direct or indirect

• Direct: excitatory (releasing neurons from inhibition)
• Indirect: inhibitory (suppressing neurons further)

Question 7

How does the cerebellum influence movement?

Answer 7

Processes sensory information and interacts with the UMNs to coordinate smooth skeletal muscle movements and balance

Question 8

Where is the cerebellum? Describe its structure

Answer 8

The hindbrain found below the tentorium cerbelli in the posterior fossa

Has an outer cerebellar cortex and a subcortical cerebellar nuclei

Question 9

How does the cerebellum connect to the brainstem?

Answer 9

Via 3 peduncles: superior, inferior and middle

*insert photo

Question 10

What connects the two hemispheres of the cerebellum?

Answer 10

The vermis

Question 11

What is the white matter in the cerebellum called and what are the predominant cell types?

Answer 11

White matter: Arbor vitae

Purkinje and granule cells are predominant

Question 12

What other processes is the cerebellum involved in asides from movement?

Answer 12

Learning and memory

Question 13

Where does the cerebellum receive input from?

Answer 13

The cerebral cortex, the brainstem, ascending pathways

Question 14

Where does the cerebellum send its output?

Answer 14

Brainstem nuclei, thalamus and cerebral cortex

Question 15

Name seven signs/symptoms you would look for in a cerebellar examination and briefly describe each

Answer 15

DANISHP
D: dysdiadochokinesis: inability to perform and sustain a series of repeated movements

A: Ataxia; gross incoordination of movements

N: Nystagmus: repetitive, involuntary oscillation of the eyes

I: Intention tremor: wide tremor when performing voluntary movements

S: Slurred speech

H: Hypotonia: patient may have muscle weakness

P: Pass pointing (dysmetria); patient overshoots when touching examiners finger