Cerebellum

Location of the Cerebellum

What separates the Cerebellum from the Cerebral Cortex?

What separates the 2 Cerebellar hemispheres?

General function of the Cerebellum

Give atleast 3 applications of the function of the cerebellum.

Where does the Cerebellum receive information for balance and sight? (1 : 2 format)

• Involved with the control of muscle tone

• Paleocerebellum

• Seen on the superior surface of the cerebellum

• Separated from the Middle lobe by the Primary Fissure

Other name for the Cerebellum which means the 2nd oldest part.

• Concerned with Coordination and Voluntary Motor function

• Largest part of the Cerebellum

• Receives input from the Cerebral Hemisphere via the Middle Cerebellar Peduncle

• Situated between the Primary fissure and the Uvolonodular Fissure

Other name for the Middle / Posterior lobe which means the newest lobe

• Composed of a pair of Floccules

• Inferior to the Vermis.

• Posterior to the Uvolonodular fissure

• Related primarily to the vestibular system (Balance)

Other name for the Flocculonodular lobe which means oldest part of the cerebellum

Wide V-shaped fissure that separates the Anterior lobe from the Middle/Posterior lobe.

• Located on the inferior surface within the Middle lobe, separates the Middle lobe from the Flocculonodular lobe.

The cerebellum is composed of a gray matter outer layer and an inner white layer, in that white layer are 3 masses of gray matter, what is that structure called?

This can be regarded as a large sheet with folds lying in the Coronal or Transverse plane

Cerebellar folds

Layer of the Cerebellum that has 2 types of neurons, Stellate (outer) and Basket (inner) cells. This layer also has neuroglial cells between the structures.

This layer of the cerebellum has Purkinje cells arranged in a single layer.

Golgi type 1 neurons that are flask - shaped and is the functional unit of the cerebellar cortex.

This layer of the cerebellum is packed densely with small cells that give rise to 4 to 5 dendrites which make claw-like endings.

The functional areas of the Cerebellar cortex.

Area of the cerebellum that influences the movements of the body specifically the neck, shoulders, thorax, abdomen and hips.

This area of the cerebellum is immediately lateral to the vermis, it controls the muscles of the DISTAL parts of the limbs

This area of the cerebellum is concerned with the planning of sequential movements of the body.

• Largest cerebellar nuclei

• Shape: Crumpled bag with an opening facing medially

• Inferior of the bag is filled with white matter made up of Efferent fibers that leave the nucleus through the opening to form a large part of the Superior Cerebellar Peduncle.

Situated medial to the dentate nucleus

Consists of one or more rounded cell group that lie medial to the emboliform nucleus.

Lies near the midline in the vermis and close to the roof of the 4th ventricle.

• Composed mostly of efferent projection from the Cerebellum

• Composed of afferent projection from the VENTRAL SPINOTHALAMIC TRACT

Other name for the Superior Cerebellar Peduncle

• Mostly composed of crossed afferent fibers from the contralateral pontine nuclei in the gray substance of the basal pons

Other name for the Middle Cerebellar Peduncle

• Composed mostly of afferent fibers, and a single efferent pathway called the Fastigiobulbar tract (Juxtarestiform body)

• Sources of Entry to the Cerebellum

Other name for the Inferior Cerebellar Peduncle

Sources of Entry to the Cerebellum

Structure of the white matter that resembles a tree’s branches found in the vermis

• Don’t leave the cerebellum but connect the different regions of the organ.

• Some fibers interconnect the folia and vermis on the same side.

• Greater part of the white matter

• Proceeds to the cerebellar cortex

• Enter the cerebellum via the Inferior and Middle Cerebellar Peduncles

• Constitute the output of the cerebellum and begin as the axons of the Purkinje cells of the cortex

• The great majority of the Purkinje cells axon pass to and synapse with the neurons of the cerebellar nuclei (Fastigial, Globose, Emboliform, Dentate) and leave through

  • Dentate, Emboliform, Globose : Superior Peduncle

  • Fastigial: Inferior Peduncle

• Most of the axon cross to the opposite side and ascend as anterior spinocerebellar tract in the contralateral white column

• Some of the axon ascend as anterior spinocerebellar tract in the lateral white column of the same side

• The fibers ENTER the cerebellum through the superior cerebellar peduncle and TERMINATES in the cerebellar cortex

• Function: Info from muscle and joints

• The axons enter the posterolateral part of the latera white column on the same side and ascend as the posterior spinocerebellar tract to the medulla oblongata

• The tract ENTERS the cerebellum through the inferior cerebellar peduncle and TERMINATES in the cerebellar cortex

• Function: Info from muscle and joints

• Function: Conveys information from muscles and joints of Upper Limb

• The fibers ORIGINATE in the Nucleus Cuneatus of the Medulla Oblongata and ENTER the Cerebellar Hemisphere on the same side through the Inferior Cerebellar Peduncle.

• Origin: Dentate Nucleus

• Destination: C/L ventrolateral nucleus of the thalamus and then to the C/L motor cerebral cortex.

  • Corticospinal tract crosses the midline and controls IPL motor neurons in SC.

• Function: IPL motor activity

  • Travels through the superior cerebellar peduncles

• Origin: Fastigial Nucleus

• Destination: IPL and C/L lateral vestibular nuclei

  • (both lateral vestibular nuclei on either side); vestibulospinal tract to IPL motor neurons in SC.

• Function: IPL extensor muscle tone

  • Travels through inferior cerebellar peduncles

• Origin: Fastigial Nucleus

• Destination: Neurons of reticular formation.

  • Reticulospinal tract to IPL motor neurons to the SC.

• Function: IPL muscle tone

  • Travels through the inferior cerebellar peduncles. \n