Nb2 - Cerebellum

Front 1

General function of the cerebellum is...
And cerebellar control of this type of activity is...

Back 1

General function of the cerebellum is coordination of somatic motor activity

Cerebellar control of motor activity is unconscious

Front 2

The cerebellum controls what
side of the body.

Back 2

The cerebellum controls the ipsilateral
side of the body.

Symptoms of a unilateral
cerebellar lesion appear on the ipsilateral
side of the body.

Front 3

Symptoms of a cerebellar lesion - DYSEQUILIBRIUM; results from what?

Back 3

is the inability to maintain proper balance. This symptom results mainly from disruption of input from the vestibular system.

Front 4

Symptoms of a cerebellar lesion - HYPOTONIA; results from what?

Back 4

is decreased muscle tone and difficulty in maintaining posture. This symptom results from disruption of spinocerebellar inputs.

Front 5

Symptoms of a cerebellar lesion - ASYNERGIA; results from what?

Back 5

is the lack of coordination of muscles which usually work together. This symptom can result from damage to pathways from higher levels (cortico-ponto-cerebellar) or to lower levels (spinal cord).

Front 6

Symptoms of a cerebellar lesion - ATAXIA

Back 6

is the inability to coordinate voluntary movements so that patient tends to fall toward the side of the lesion.

Front 7

Symptoms of a cerebellar lesion - INTENTION TREMOR

Back 7

is a tremor that appears just before the patient makes a planned movement.

Front 8

General info on cerebellar lesion

Back 8

Lesion of the cerebellum produces no real loss (no paralysis), but a General Inadequacy of Function.

There is a high degree of COMPENSATION which follows a cerebellar lesion.

Front 9

Deep transverse fissures run parallel to the folia and divide the cerebellum into three main lobes. What are they? Each lobe contains what...(3)

Back 9

The three cerebellar lobes are called the ANTERIOR, POSTERIOR, and FLOCCULONODULAR LOBES.

Each lobe contains vermis, intermediate zone, and cerebellar hemispheres

Front 10

Primary fissure separates what?

Back 10

Primary fissure separates the anterior and posterior lobes.

Front 11

Posterolateral fissure separates what?

Back 11

Posterolateral fissure separates the posterior and flocculonodular lobes.

Front 12

Divisions of cerebellum are based on evolution and inputs. What consists mainly of the flocculonodular lobe and where are its inputs from?

Back 12

Archicerebellum is the oldest phylogenetically; called the Vestibulocerebellum due to its major inputs from the vestibular system. Consists mainly of the flocculonodular lobe.

Front 13

Divisions of cerebellum are based on evolution and inputs. What consists mainly of the anterior lobe and where are its inputs from?

Back 13

Paleocerebellum, the second oldest part, called the Spinocerebellum, due to its inputs coming mainly from spinal cord. Consists mainly of the anterior lobe

Front 14

Divisions of cerebellum are based on evolution and inputs. What consists mainly of the posterior lobe and where are its inputs from?

Back 14

Neocerebellum, the newest part, called the Cerebrocerebellum, due to its inputs mainly from cerebral cortex via the pons. Consists mainly of the lateral hemispheres of the posterior lobe.

Front 15

Cerebellar inputs and outputs form three pairs of large fiber bundles. What are they and what do they do?

Back 15

The cerebellar peduncles (inferior, middle, superior) connect the cerebellum to the brainstem.

Front 16

Inferior cerebellar peduncle mainly contains what and what does it attach?

Back 16

Inferior cerebellar peduncle mainly contains fibers entering the cerebellum, but also outputs to the medulla oblongata, the vestibular nuclei and reticular formation.

Attaches the cerebellum to the Medulla Oblongata.

Front 17

Middle cerebellar peduncle mainly contains what and what does it attach?

Back 17

Middle cerebellar peduncle contains fibers entering the cerebellum from the pons.

Attaches the cerebellum to the Pons.

Front 18

Superior cerebellar peduncle mainly contains what but what is the exceptions? What does it attach?

Back 18

Superior cerebellar peduncle mainly contains outputs of the cerebellum to the red nucleus and VA/VL thalamus.

One exception is inputs from the spinal cord, the ventral spinocerebellar tract.

Attaches cerebellum to midbrain.

Front 19

The cerebellar surface has grey matter called...

Back 19

Grey matter on the surface
of cerebellum (under the pia mater) is called
the Cerebellar Cortex

Front 20

White matter lies where and is called what?

Back 20

White matter lies
deep to the grey matter
and is called the
Medullary Center. It is an intermediate part that contains fibers coming/going to the cerebellar cortex

Front 21

The deepest part consists of four pairs of cerebellar nuclei. What are they called as a group and what are their names?

Back 21

The deepest part consists of four pairs of cerebellar nuclei, which are called “Deep Cerebellar Nuclei”, located just dorsal to the fourth ventricle.

1) Fastigial nucleus lies close to the midline.

2) Globose nucleus consists of several small groups of grey matter found lateral to fastigial nucleus.

3) Emboliform nucleus is a wedge-shaped, grey matter found lateral to globose nucleus.

4) Dentate nucleus is the largest and most laterally placed of the deep nuclei. Resembles the anatomy of the inferior olivary nucleus.

Front 22

There are 5 major sources
of inputs to the cerebellum.

Back 22

1) Spinal Cord
2) Inferior Olivary Nucleus
3) Reticular Formation
4) Vestibular Nuclei Axons and Vestibular Ganglion Cell Axons
5) Cerebral Cortex

Front 23

There are 5 major sources
of inputs to the cerebellum - Spinal Cord - 3 Tracts found here

Back 23

1. Dorsal spinocerebellar tract
2. Ventral spinocerebellar tract
3. Cuneocerebellar tract

Front 24

Spinal Cord - Dorsal spinocerebellar tract

Back 24

a. Originates from nucleus Dorsalis of Clark (C8-L2).

b. Travels on the ipsilateral side of spinal cord/brainstem.

c. Enters the inferior cerebellar peduncle.

d. Synapses mainly in the anterior lobe of cerebellum.

e. Conveys information regarding the lower extremity muscle tone.

Front 25

Spinal Cord - Ventral spinocerebellar tract

Back 25

a. Originates from the posterior horn of spinal cord (all levels of spinal cord).

b. Axons cross in the anterior commissure of spinal cord.

c. Enters cerebellum in superior cerebellar peduncle and projects to the anterior lobe.

d. Conveys information about whole muscle movement.

Front 26

Spinal Cord - Cuneocerebellar Tract

Back 26

a. First-order neurons are dorsal root ganglion cells whose axons ascend in the dorsal funiculus to synapse in the lateral (external) cuneate nucleus in the medulla oblongata, located at the level of nucleus cuneatus.

b. Axons of neurons in the lateral cuneate nucleus form the cuneocerebellar tract, which enters the cerebellum from the inferior cerebellar peduncle and projects to the anterior lobe.

c. Conveys information regarding muscle tone for the upper extremity.

Front 27

There are 5 major sources
of inputs to the cerebellum - Inferior Olivary Nucleus

Back 27

1. Axons cross in the medulla oblongata to enter the cerebellum in the inferior cerebellar peduncle.
2. Axons project to the entire cerebellar cortex.

Front 28

There are 5 major sources
of inputs to the cerebellum - Reticular Formation

Back 28

1. Axons enter cerebellum in the inferior cerebellar peduncle.
2. Axons project mainly to the spinocerebellum.

Front 29

There are 5 major sources
of inputs to the cerebellum - Vestibular Nuclei Axons and Vestibular Ganglion Cell Axons

Back 29

1. Axons enter cerebellum in the inferior cerebellum peduncle.
2. Axons project mainly to vestibulocerebellum.

Front 30

There are 5 major sources
of inputs to the cerebellum - Cerebral Cortex

Back 30

1. Axons from cerebral cortex synapse in pontine grey nuclei.
2. Axons of pontine grey nuclei form pontocerebellar axons which cross in pons to enter the cerebellum by the middle cerebellar peduncle.
3. Wide motor areas of cerebral cortex project to the cerebellum via the pons.

Front 31

Cerebellar cortex samples all incoming fibers. Two fiber classes identified...

Back 31

All incoming fibers to the cerebellum appear as MOSSY FIBERS, except those fibers coming from the inferior olive which are called CLIMBING FIBERS.

**Both send collaterals to the deep cerebellar nuclei.

Front 32

Cerebellar cortex has three layers. From outermost (next to pia mater) to innermost (next to white matter), they are the following:

Back 32

1) Molecular Layer
2) Purkinje Layer
3) Granular Layer

Front 33

Molecular Layer

Back 33

Molecular layer is located next to surface of cerebellum under the pia mater. This layer contains large bundles of parallel fibers and dendrites of the Purkinje cells.

Front 34

Purkinje Layer

Back 34

Purkinje cell layer consists of a monolayer of Purkinje cell bodies. Dendrites of Purkinje cells in molecular layer receive excitatory synapses from parallel fibers and climbing fibers. Purkinje cell axons exit cerebellar cortex to synapse on neurons in deep cerebellar nuclei. Purkinje cells are inhibitory.

Front 35

Granular Layer

Back 35

Granular layer contains granule cells whose axons form the parallel fibers, which run in molecular layer and synapse on dendrites of Purkinje cells. Parallel fibers are excitatory.

Front 36

Mossy fibers

Back 36

Mossy fibers originate from neurons in spinal cord, reticular formation, vestibular system, and pons. Synapse mainly with granule cells. Mossy fibers are excitatory.

Front 37

Climbing Fibers

Back 37

Climbing fibers originate only from neurons in inferior olive. Synapse mainly on dendrites of Purkinje cells. Climbing fibers are excitatory.

Front 38

Outputs of the cerebellar cortex.

Back 38

Purkinje cells are only neurons whose axons leave the cerebellar cortex, and they mainly go to cerebellar deep nuclei.

Front 39

What compose the main output of the entire cerebellum?

Back 39

Axons of deep cerebellar nuclei compose the main output of the entire cerebellum. These axons are excitatory.

The deep cerebellar nuclei receive major inputs from PURKINJE CELL AXONS, and also *collaterals from inputs to cerebellum* going to cerebellar cortex as climbing fibers and mossy fibers.

Front 40

Fastigial nucleus - Receives inputs from what, outputs to what, concerned with what

Back 40

Fastigial nucleus lies closest to the midline. This nucleus receives inputs from the Purkinje cells of vermis and also vestibular nuclei directly. Output to the vestibular nuclei and reticular formation. Concerned with extensor muscle tone.

Front 41

Globose nucleus - Receives inputs from what, outputs to what, concerned with what

Back 41

Globose nucleus consists of several small groups of grey matter found lateral to fastigial nucleus. Receives inputs from Purkinje cells in intermediate zone. Output to red nucleus mainly, but also VL/VA thalamus. Concerned with flexor muscle tone.

Front 42

Emboliform nucleus - Receives inputs from what, outputs to what, concerned with what

Back 42

Emboliform nucleus is a wedge-shaped, grey matter found lateral to globose nucleus. Has the same inputs, outputs, and function as the globose nucleus.

Front 43

Dentate nucleus - Receives inputs from what, outputs to what, concerned with what

Back 43

Dentate nucleus is the largest and most laterally placed of the deep nuclei. Receives most of its inputs from Purkinje cells located in the lateral cerebellar hemispheres. Output goes to the red nucleus and VL/VA thalamus. Concerned with coordinating somatic motor activity by influencing motor regions of cerebral cortex indirectly.