CEREBELLUM

Question 1

he branching pattern of the white matter OF THE CEREBELLUM was referred to by early anatomists as the _______

Answer 1

arbor vitae

Question 2

transverse fissures of the cerebellum

Answer 2

anterior and posterolateral or prenodular

Question 3

e cortex of the vermis projects to the
______

that of the paravermis to the

and that of the cerebellar hemisphere to the dentate nucleus.

Answer 3

fastigial deep cerebellar nucleus

interposed deep nuclei (emboliform and globose),

Question 4

________has reciprocal connections with vestibular and reticular nuclei and plays a role in control of body equilibrium and eye movement.

Answer 4

vestibulocerebellum (corresponds best with the flocculonodular lobe)

Question 5

__________has reciprocal connections with the spinal cord and plays a role in control of muscle tone as well as axial and limb movements, such as those used in walking and swimming

Answer 5

The spinocerebellum (corresponds best to the anterior lobe)

Question 6

_________has reciprocal connections with the cerebral cortex and plays a role in planning and initiation of movements, as well as the regulation of discrete limb movements.

Answer 6

The cerebrocerebellum or pontocerebellum (corresponds best to the posterior lobe)

Question 7

In the _____, the body appears inverted, with hindlimbs represented rostral to the forelimbs and face.

Answer 7

anterior lobe of the cerebellum

Question 8

layers of the cerebellar cortex

Answer 8

Outer molecular layer (about 300 µm in thickness)

Middle Purkinje cell layer (about 100 µm in thickness)

Innermost granule cell layer (about 200 µm in thickness)

Question 9

cell types in each layer

Answer 9

Basket and stellate cells are in the molecular layer,

Purkinje cells are in the Purkinje cell layer,

and granule and Golgi cells are in the granule cell layer.

Question 10

Purkinje cell

Answer 10

courses through the granule cell layer and deep white matter to project on deep cerebellar nuclei

Question 11

Intrinsic neurons of the cerebellum

Answer 11

Basket cell
Stellate
Granule cell
Golgi II cell

Question 12

Basket cells

Answer 12

situated in deeper parts of the molecular layer in close proximity to Purkinje cells.

Question 13

______located in the superficial and deeper parts of the molecular layer.

Answer 13

Stellate cells

Question 14

Difference between stellate and basket cells

Answer 14

The difference lies in the fact that stellate cells establish contact with the dendrites of Purkinje cells, whereas basket cells establish contact with dendrites, perikarya, and axons of Purkinje cells.

Question 15

_______ are among the smallest cells in the brain (6 to 9 µm) and fill the granule cell layer.

Answer 15

Granule cells

Question 16

________occupy the superficial part of the granule cell layer adjacent to the Purkinje cells. They are large neurons, about the same size as the Purkinje cell bodies.

Answer 16

GOLGI II CELLS

Question 17

Axons of Golgi cells take part in the formation of the ______. They are characterized by a dense arborization of short axonal branches that span the entire granule cell layer

Answer 17

Glomerulus

Question 18

They are the sites of synaptic contact between the incoming cerebellar fibers (mossy fiber system) and processes of neurons within the granule cell layer.

Answer 18

Glomerulus

Question 19

Glomerulus

Answer 19

Cerebellar input via the mossy fiber system
Dendrites of granule cells
Axon terminals of Golgi neurons
Proximal parts of Golgi dendrites

Question 20

The three major sources of afferents of the cerebellum:

Answer 20

are the spinal cord, vestibular system, and cerebral cortex.

Question 21

Inputs from the spinal cord are transmitted to the cerebellum via the :________
These tracts provide the cerebellum with information related to the position and condition of muscles, tendons, and joints.

Answer 21

dorsal and ventral spinocerebellar tracts and the rostral extension of the dorsal spinocerebellar tract, the cuneocerebellar tract.

Question 22

___________provide information related to body equilibrium.

Answer 22

Vestibulocerebellar inputs

Question 23

Cortical inputs to the cerebellum originate in:

This is for planning and initiation of movement

Answer 23

neocortical as well as paleocortical and archicortical areas.

Question 24

Other inputs:

________ (A-6 cell group of primates), a dopaminergic projection from the ventral tegmental area of Tsai in the midbrain (A-10 cell group of primates)

_______projection from the raphe nuclei (B-5 and B-6 cell groups of primates) in the brain stem.

Answer 24

locus ceruleus

serotonergic

Question 25

TRACTS FROM TO THE CEREBELLUM VIA ICP: 1. Dorsal spinocerebellar tract _____ 2. Cuneocerebellar tract _______ 3. Olivocerebellar tract ________ 4. Reticulocerebellar tract _________ 5. Vestibulocerebellar tract _____ 6. Arcuatocerebellar tract ________ 7/ Trigeminocerebellar tract _____

Answer 25

1. from the dorsal nucleus of Clarke 2. from the accessory cuneate nuclei 3. from the inferior olivary nuclei (major component) 4. from the reticular nuclei of the brain stem 5. (both primary afferents from the vestibular end organ and secondary afferents from the vestibular nuclei) 6. from the arcuate nuclei of the medulla 7. From the spinal and main sensory nuclei of the trigeminal nerve

Question 26

fiber tracts to cereb via MCP

Answer 26

Pontocerebellar Serotonergic fibers from the raphe nuclei

Question 27

tracts into cerebellum via Superior Cerebellar Peduncle

Answer 27

Ventral spinocerebellar tract Trigeminocerebellar tract from the mesencephalic trigeminal nucleus Cerulocerebellar tract from the nucleus ceruleus Tectocerebellar tract from the superior and inferior colliculi

Question 28

It is generally believed that the _______is the major component of the climbing motor system.

Answer 28

olivocerebellar tract

Question 29

Stimulation of the climbing fiber system elicits a ________ from the Purkinje cell capable of overriding any ongoing activity in that cell.

Answer 29

prolonged burst of high-frequency action potentials (complex spike)

Question 30

The _______ includes all afferents to the cerebellum except those which contribute to the climbing fibers and the multilayered fiber system

Answer 30

mossy fiber system

Question 31

This recently described fiber system includes afferents to the cerebellum from the hypothalamus, as well as the serotonergic input from the raphe nuclei, the noradrenergic input from the nucleus locus ceruleus, and the dopaminergic input from the mesencephalic dopaminergic neurons

Answer 31

MULTILAYERED FIBER SYSTEM

Question 32

Similar to the climbing and mossy fiber systems, the multilayered fiber system projects on neurons in the_____

Answer 32

cerebellar cortex and the deep cerebellar nuclei.

Question 33

The _______ is composed of multipolar neurons and resembles the inferior olive in configuration

Answer 33

The dentate nucleus

Question 34

DENTATE NUCLEUS: | The _______ input is inhibitory, whereas the inputs from ______ are excitatory to the dentate nucleus

Answer 34

Purkinje cell Climbing and mossy

Question 35

The bulk of axons of the dentate nucleus project via the superior cerebellar peduncle (brachium conjunctivum) to the____________

Answer 35

to the contralateral ventrolateral nucleus of the thalamus.

Question 36

The interposed nuclei receive afferent fibers from the following sources (Figure 15-19):

Answer 36

Axons of Purkinje cells in the paravermal (intermediate) zone of the cerebellum that are inhibitory in function Collaterals from climbing and mossy fiber systems that are excitatory in function

Question 37

Axons of interposed nuclei leave the cerebellum via the:

Answer 37

superior cerebellar peduncle (brachium conjunctivum).

Question 38

This nucleus is located in the roof of the fourth ventricle medial to the globose nucleus; hence it is called the roof nucleus

Answer 38

Fastigial Nucleus

Question 39

Fastigial Nucleus receives afferent fibers from the following sources

Answer 39

Axons of Purkinje cells in the vermis of the cerebellum that are inhibitory in function Collaterals of mossy and climbing fiber systems that are excitatory

Question 40

The cerebral cortex communicates with the cerebellum via the:

Answer 40

Corticoolivocerebellar via the red nucleus and inferior olivary nucleus Corticopontocerebellar via the pontine nuclei Corticoreticulocerebellar via the reticular nuclei of the brain stem

Question 41

cerebellum influences the cerebrum mainly via _________

Answer 41

the dentatothalamic system.

Question 42

he following neurotransmitters have been identified in the cerebellum:

Answer 42

gamma-aminobutyric acid (GABA): Inh taurine: Inh of the superficial stellate cells glutamate: excitatory neurotransmitter of granule cells aspartate; xcitatory neurotransmitter in climbing and mossy fibers acetylcholine: granule cells, Golgi cells, and mossy fibers norepinephrine: inhibitory neurotransmitter of the locus ceruleus projection on Purkinje cell dendrites. serotonin, and dopamine

Question 43

Cerebellar neurons are characterized by _____ of resting impulse discharge.

Answer 43

high rates

Question 44

Stimulation of the mossy fiber system or of the parallel fibers (axons of granule cells) elicits in the Purkinje cell a brief ________followed by a prolonged ________

Answer 44

excitatory postsynaptic potential (EPSP) (simple spike) lasting 5 to 10 ms, inhibitory postsynaptic potential (IPSP).

Question 45

Stimulation of the climbing fiber system elicits in the Purkinje cell an intense and prolonged reaction characterized by an initial large spike followed by several small ones. This is called:

Answer 45

complex spike

Question 46

A delay in the initiation of each successive movement will lead to the _________

Answer 46

adiadochokinesis (disturbance in performance of rapid movement using antagonistic muscle groups) of cerebellar disease.

Question 47

A delay in the termination of movement results in_____

Answer 47

dysmetria

Question 48

Thus, ___________are the result of an error in timing.

Answer 48

adiadochokinesis and dysmetria

Question 49

__________ is due to defective feedback control from the cerebellum on cortically initiated movement

Answer 49

Intention (volitional) tremor

Question 50

The cerebellum also influences movement via its effects on the_________. The cerebellum normally increases the sensitivity of muscle spindles to stretch.

Answer 50

gamma system.

Question 51

The archicerebellum and paleocerebellum influence spinal activity via the

Answer 51

vestibulospinal and reticulospinal tracts.

Question 52

Archicerebellar signs are usually associated with lesions in the flocculonodular lobe and are manifested by :

Answer 52

truncal ataxia (staggering gait and unsteady posture while standing) and nystagmus (rhythmic oscillation of the eyes at rest and/or with ocular movements

Question 53

The increase in myotatic and postural reflexes associated with the anterior lobe syndrome is due to an increase in motor signals to the ______ neurons and a simultaneous decrease in signals to the ____

Answer 53

Alpha gamma system.

Question 54

The objective of ___________ is to reduce the slip of a visual image over the fovea to velocities slow enough to allow clear vision.

Answer 54

smooth pursuit eye movements

Question 55

_________and the ________to which it projects are necessary for horizontal saccades and make them fast, accurate, and consistent.

Answer 55

posterior lobe vermis (oculomotor vermis) caudal nucleus fastigii

Question 56

Damage to the ______ has been shown to impair rapid and accurate mental shifts of attention between and within sensory modalities

Answer 56

cerebellum

Question 57

Non-motor fn of archicerebellum

Answer 57

Primitive autonomic responses, emotion, affect, sexuality, affectively important memory (“limbic” cerebellum)

Question 58

Non-motor fn of Neocerebellum

Answer 58

Modulation of thought, planning, strategy formation, spatial and temporal parameters, learning, memory, language

Question 59

_________may serve a modulatory role for emotional reactions

Answer 59

fastigial nucleus

Question 60

The cerebellum is supplied by three long circumferential arteries arising from the vertebral basilar system:

Answer 60

(1) the posterior inferior cerebellar artery (PICA), (2) the anterior inferior cerebellar artery (AICA), and (3) the superior cerebellar artery (SCA).

Question 61

posterior inferior cerebellar artery (PICA) arises from the rostral end of the vertebral artery and supplies the:

Answer 61

inferior surface of the cerebellum , including the cerebellar hemispheres, inferior vermis, and the tonsils. It also supplies the choroid plexus of the fourth ventricle and gives collaterals from its medial branch to supply the dorsolateral medulla.

Question 62

anterior inferior cerebellar artery (AICA) arises from the caudal third of the basilar artery. Because of its usual small size, it supplies _______

Answer 62

a small area of the anterolateral part of the inferior surface of the cerebellum

Question 63

When there is a large AICA, ________ hypoplastic, and the AICA territory then encompasses the whole anteroinferior aspect of the cerebellum.

Answer 63

the ipsilateral PICA

Question 64

________is the most constant in caliber and territory of supply.

Answer 64

SCA the SCA supplies most of the superior surface of the cerebellar hemisphere and vermis

Question 65

The cerebellum is drained by three veins: superior, posterior, and anterior.

Answer 65

superior, empties into the great cerebral vein of Galen posterior: empties into the straight or transverse sinus anterior (petrosal): empties into the superior or inferior petrosal sinus.