Final Exam

Question 1

What is involved in the control of complex movements?

Answer 1

Cerebral Cortex
Basal Ganglia
Cerebellum
Thalamus
Brain Stem
Spinal Cord

Question 2

Describe the Primary motor cortex

Answer 2

somatotopic arrangement
greater than 1/2 controls hands & speech
Stimulation of neuron stimulate movements instead of contracting a single muscle

Question 3

Describe the Premotor Area

Answer 3

anterior to lateral portions of primary motor cortex below supplemental area
projects to primary motor cortex and basal ganglia

Question 4

Origins of the Corticospinal tract

Answer 4

Primary Motor Cortex- 30%
Premotor and Supplemental Areas- 30%
Somatic sensory areas- 40%

Question 5

Ventral corticospinal tract

Answer 5

Fibers stay ipsilateral

Question 6

Lateral corticospinal tract

Answer 6

Fibers cross midline (contralateral)

Question 7

Describe the Supplemental motor area

Answer 7

-superior to premotor area lying mainly in the longitudnal fissure
-functions in concert with premotor area to provide:
attitudinal movements
fixation movements
positional movements of head & eyes
background for finer motor control of arms/hands

Question 8

What is Spinal preparation?

Answer 8

All tracts cut, cord completely isolated from brain (flaccidity)
Occurs low brain stem

Question 9

What is Decerebrate preparation?

Answer 9

Transection at mid collicular level. Extensors are tonically hyperactive (rigidity)

Question 10

What is Decorticate preparation?

Answer 10

Destruction of the cerebral cortex. Creates spasticity due to tonic excitation from upper areas of the reticular formation no longer under inhibitory cortical influence (release phenomenon)

Question 11

Describe Decorticate Spasticity.

Answer 11

Removal or lesion of cerebral cortex
loss of cortical inhibition of gamma efferent discharge mediated by the medullary reticular formation
seen in humans on the hemiplegic side after stroke
small arteries in internal capsul prone to rupture or thrombosis
60% of intracerebral hemorrhages

Question 12

What is an experimental procedure useful for the study of reflexes?

Answer 12

Decerebration

Question 13

What are the specifics of Decerebration?

Answer 13

Transection of midbrain often at intercollicular level
loss of sensation
motor contro is altered
-cortical descending pathways are interrupted but brain stem control remains intact