L05 Schetz Motor Sys Block_Cerebellum_BasalGanglia_HigherMotorControl

Question 1

Explain the importance of the relative position of the cerebellum to the fourth ventricle

Answer 1

It means that mass lesions, swelling (eg edema following an infarct) or compression injury of cerebellum can lead to obstructive hydrocephalus. Other examples: tumors (esp. astrocytomas), hypertensive hemorrhage, chiari malformations.

Question 2

flocculus

Answer 2

Projects to vestibular nuclei of medulla; posture, balance.

Question 3

nodulus

Answer 3

Projects to vestibular nuclei of medulla; posture, balance.

Question 4

vermis

Answer 4

Projects to fastigial nucleus. Subserves trunk/midline structures.

Question 5

intermediate zone

Answer 5

Projects to nucleus interpositus (globose and emboliform). Subserves trunk/midline structures.

Question 6

lateral hemispheres

Answer 6

Project to dentate nuclei. Subserve the extremities.

Question 7

fastigial nucleus

Answer 7

Recieves input from the vermis; subserves midline/trunk structures.

Question 8

nucleus interpositus

Answer 8

(Globose and emboliform nuclei) Receives input from the intermediate zone. Subserves midline/trunk structures.

Question 9

dentate nucleus

Answer 9

Receives input from the lateral hemispheres of the cerebellum. Subserves the extremities.

Question 10

Name the 5 major components of the molecular layer of the cerebellum.

Answer 10

Cells: stellate cell bodies, basket cell bodies. Axons: Purkinje dendrites, granule prallel fibers, Golgi dendrites.

Question 11

Name the 2 major components of the Purkinje cell layer of the cerebellum.

Answer 11

Pukinje cell bodies, basket projections

Question 12

Name the 3 major components of the granule cell layer.

Answer 12

Granule cell bodies, Golgi cell bodies, mossy fiber connections

Question 13

climbing fibers

Answer 13

From inferior olive to Purkinje cells; also send collaterals to deep nuclei. Glutamatergic.

Question 14

mossy fibers

Answer 14

From various tracts (spinal cord, vestibular and pontine nuclei) to granule cells; also send collaterals to deep nuclei. Glutamatergic.

Question 15

aminergic fibers

Answer 15

From locus coeruleus (NE) and raphe nuclei (Ser) to cerebellum.

Question 16

Which is the only excitatory cell type of the cerebellum?

Answer 16

Granule cells

Question 17

Purkinje cells

Answer 17

Receive glutamate signal from either inferior olive (via climbing fibers) or granule cells (via mossy fibers). Inhibit deep nuclei.

Question 18

Granule cells

Answer 18

Activate Purkinje cells OR activate basket cells and stellate cells via parallel fibers (to inhibit Purkinje cells) OR activate Golgi cells via to autoinhibit.

Question 19

Stellate cells

Answer 19

Inhibitory interneuron in the molecular layer of the cerebellum.

Question 20

Golgi cells

Answer 20

Inhibitory interneuron in the granular layer of the cerebellum.

Question 21

What tracts does the inferior cerebellar peduncle carry?

Answer 21

4: ipsilateral dorsal spino- tract (proprioceptive inputs from body); ipsilateral cuneo- tract; contralateral olivo- tracts (proprioceptive input from whole body); vestibulo-.

Question 22

What tracts does the middle cerebellar peduncle carry?

Answer 22

1: contralateral ponto- (which receives input from many areas of cortex)

Question 23

What tracts does the superior cerebellar peduncle carry?

Answer 23

2: contralateral dentatorubrothalamocortical tract; ventral spino- (proprioception, fine touch, vibration)

Question 24

What SSx would be present if the nodulus or flocculi were lesioned?

Answer 24

Falling and nystagmus (both IPSILATERAL)

Question 25

What SSx would be present if the vermis or intermediate zone were damaged?

Answer 25

Truncal ataxia = “drunken” gait

Question 26

What SSx would be present if the lateral hemispheres of the cerebellum were lesioned?

Answer 26

Dysdiadochokinesia, dysmetria, ataxia of the extremities, and asynergy.

Question 27

Name/define 6 major signs of cerebellar dysfunction.

Answer 27

1. Hypotonia2. Ataxia (gait, midline)3. Dysmetria (putting a limb somewhere specific in space) 4. Dysdiadochokinesia (fish out of water)5. Rebound phenomenon (loss of normal antagonistic checks; don’t hit yourself!)6. Intention tremor

Question 28

define athetosis

Answer 28

Ceaseless, slow, writhing, involuntary movements (esp in hands)

Question 29

define chorea

Answer 29

Ceaseless, rapid, highly complex and jerky involuntary movements.

Question 30

define asynergy

Answer 30

Loss of coordination

Question 31

define ataxia

Answer 31

Inability to coordinate voluntary movement

Question 32

What are the contents of the anterior limb of the internal capsule?

Answer 32

Thalamocortical, corticothalamic, and frontopontine fibers (and transverse from caudate to putamen)

Question 33

Waht are the contents of the posterior limb of the internal capsule?

Answer 33

Corticobulbar (genu) and corticospinal tracts (f a l), corticorubral, and then sensory in the posterior portion.

Question 34

Which components of the basal ganglia are excitatory? What neurotransmitter(s) do they use?

Answer 34

The ACh neurons in the striatum and the glutamatergic eurons of the subthalamic nucleus.

Question 35

Lesioning which two structures can serve as a treatment for Parkinson’s?

Answer 35

STN and GPi

Question 36

Which MAO-B inhibitor is used for PD?

Answer 36

Selegiline

Question 37

Which antiviral agent also acts as a weak antiglutamatergic (treatment for PD)?

Answer 37

Amantadine

Question 38

Which peripheral AAAD inhibitor is given with L-DOPA to avoid emesis?

Answer 38

Carbidopa

Question 39

Causes and SSx of myotonia

Answer 39

Mutations in ion channels of the muscle membrane. Results in slow relaxation of muscles after contraction (stiffness).

Question 40

Werdnig-Hoffman disease is an infantile form of _________ that is generally lethal.

Answer 40

Spinal muscular atrophy

Question 41

Kugelberg-Welander disease is a juvenile form of _______ that leads to disability.

Answer 41

Spinal muscular atrophy