Lecture 5

Question 1

What accounts for more cells in the cerebellum than the cerebrum?

Answer 1

folia, higher density, smaller cells

Question 2

Three lobes of the cerebellum?

Answer 2

anterior, posterior, flocculonodular

Question 3

First lobe formed during development in the cerebellum.

Answer 3

flocculonodular, in between anterior (formed 2nd) and posterior (formed 3rd)

Question 4

Deep Cerebellar Nuclei

Answer 4

3 sets within deep white matter; fastigial, globose and emboliform (interposed), dentate

Question 5

Fastigial Nucleus

Answer 5

associated with vermal zone, oldest portion, closest to the midline, medial descending systems–>motor execution

Question 6

Globose and Emboliform (Interposed) Nuclei

Answer 6

associated with paravermal zone, lateral descending systems–>motor execution

Question 7

Dentate Nucleus

Answer 7

newest portion and most important, controls coordination, associated with the lateral physiologic zone

Question 8

Vermal Zone

Answer 8

vestibulocerebellum, controls balance and equilibrium, midline

Question 9

Paravermal Zone

Answer 9

spinocerebellum; gets a huge amount of proprioceptive input from the body; length, tightness, movement of muscles; surrounding vermal

Question 10

Lateral Zone

Answer 10

neocerebellum, gets its information from the neocortex; comparator system, compares information from cortex to information from the body about movement, sends out corrective signals; lateral to paravermal zone

Question 11

What occurs when a patient has a neocerebellar tumor?

Answer 11

movements will be jerky (ataxia), can’t send out corrective signals

Question 12

Nystagmus

Answer 12

Pt will have a problem of conjugate eye movement which may originate in the cerebellum

Question 13

Inferior Cerebellar Peduncle

Answer 13

smallest, contains the Dorsal Spinocerebellar tract - carrying sensory information from muscle spindles, GTO (all proprioceptive info), “what you are actually doing”, contains the Cuneocerebellar tract - information from the neck region, where your head goes your body will follow

Question 14

Middle Cerebellar Peduncle

Answer 14

laterally from pons and largest of all the peduncles, contains Corticopontocerebellar tract - carries the motor “plan” (what you want to do)

Question 15

Superior Cerebellar Peduncle

Answer 15

Ventral and Rostral Spinocerebellar Tract - carrying proprioceptive information; Dentorubral and Dentothalamic tracts - output information from deep cerebellar nuclei to red nucleus and eventually thalamus

Question 16

Juxtarestiform Body

Answer 16

olivocerebellar tract

Question 17

Morphological Organization of the Cerebellum

Answer 17

Molecular Layer - relatively cell free; Purkinje Cell Layer - one cell layer thick (very large cells); Granule Cell Layer - looks grainy because the cells are densely packed

Question 18

Two different types of input into cerebellum.

Answer 18

Inputs can arise from spinal cord (external cuneate nucleus, reticular nuclei, or pontine nuclei) - strong excitatory in nature and are called mossy fibers; Inputs can arise from the inferior olivary nucleus - very excitatory in nature

Question 19

All output in the cerebellum is from ________ ____.

Answer 19

Purkinje cells - travel to deep cerebellar nuclei and is strongly inhibitory in nature

Question 20

Hypotonia

Answer 20

reduced muscle tone

Question 21

What can result from lesions of the cerebellum?

Answer 21

hypotonia, asynergia hypo- or hyperdysmetria, lack of check (rebound), terminal “intention” tremor, dysdiadochokinesia

Question 22

Asynergia

Answer 22

uncoordinated

Question 23

Hypo- or Hyperdysmetria

Answer 23

Unable to measure distances correctly, pt will either not reach far enough or reach too far and knock it over

Question 24

Lack of Check (Rebound)

Answer 24

pt will not be able to stop muscles from rebounding

Question 25

Dysdiadochokinesia

Answer 25

unable to coordinate palms up and palms down repetitively

Question 26

Dysarthria

Answer 26

unable to coordinate speech (slurred)

Question 27

Granule Cell

Answer 27

send an axon up into the molecular layer; here, it will bifurcate and run the length of a folia
called a parallel fiber, will synapse on basket and stellate cells (inhibit) or direct synapse on purkinje cells (excitatory)

Question 28

After being stimulated by granule cells, they will inhibit purkinje cells.

Answer 28

stellate and basket cells

Question 29

Three functional pathways of the basal ganglia.

Answer 29

motor, cognitive, affective

Question 30

Teeter-Totter Theory

Answer 30

Need to have a biochemical balance in the brain

Question 31

Parkinson’s Disease

Answer 31

Paralysis Agitans (too little movement - too much inhibition), best known of the basal ganglia disorders, treat with dopamine but usually only works for 10 years before receptors get down-regulated and stop working

Question 32

Huntington’s Disease

Answer 32

Pt moves ALL the time (too much movement), too much excitation, looked for too much dopamine in other parts of the basal ganglia

Question 33

Fetal/Neonatal Intraparenchymal Infarcts (Cerebral Palsy)

Answer 33

Strokes within the brain of infants or neonates, lesion at or around the basal ganglia at the time of birth, Pt will present with motor problems that will either look like Parkinson’s or Huntington’s disease depending on what part of the basal ganglia is affected

Question 34

The tonsils of the cerebellum sit right in the ______ _______.

Answer 34

foramen magnum

Question 35

Why can swelling of the cerebellum be fatal?

Answer 35

herniate downwards through foramen magnum; this will put pressure on the brain stem; which will affect the cardiac regions of the medulla

Question 36

Terminal intention tremor

Answer 36

occurs towards end of motion as corrective signals are being sent (neocerebellum - lateral zone)

Question 37

Resting tremors in Parkinson’s disease.

Answer 37

In many cases this will stop when they are moving; problem in basal ganglia (Specifically substantia nigra)

Question 38

Essential tremor.

Answer 38

tremors that occur all the time

Question 39

Why is the cerebellum affected by alcohol before the cerebrum?

Answer 39

it has more cells and the BBB

Question 40

Archicerebellum

Answer 40

Vestibulospinal system, Vermal zone to fastigial nuclei, Balance

Question 41

Paleocerebellum

Answer 41

Rubrospinal System, Girdle control: control stability before you can have mobility

Question 42

Neocerebellum

Answer 42

Corticospinal System, rest of the volitional control of the body

Question 43

Climbing fibers and mossy fibers come through the _______ cerebellar peduncle to cerebellum.

Answer 43

inferior

Question 44

Enlargement of lateral ventricles is a tip off for ____________ __________.

Answer 44

Huntington’s Disease, caudate nucleus atrophy