cerebellum

basal ganglia

• Decision to move

• Direction of movement

• Amplitude of movement

• Motor expression of emotions

cerebellum

• Coordination and prediction of movement

• Mediates skilled manipulation of muscles

afferent information

• Receives information from the PNS about position of the body (proprioception), the position of the head (vestibular), muscle tone, and other visual, auditory, and tactile information from the environment.

• Compares and integrates the information with the plans for movement receive from the cortex.

• Can predict the consequence of movement (oneself and others)

• Calculates trajectory and behavioral outcomes

efferent information

• sent from the cerebellum through deep cerebellar nuclei. Projects To the cerebral cortex through red nucleus and thalamus

truncal stability

• bilateral

limb movement

ipsilateral

• Refers to the control and coordination of movements of the limbs on the same side of the body as the cerebellar hemisphere involved.

Anatomy of cerebellum

• Located in the posterior cranial fossa

• Lies over the 4^th ventricle

• Connected to the brainstem by 3 cerebellar peduncles

right and left cerebellum hemispheres

vermis

3 lobes of cerebellum

• Anterior, posterior, flocconodular

folds in cerebellum

folia of the cerebellum that increase surface area

cerebellar cortex

• Similar to the cerebral cortex, has a homunculus

  • Trunk is in midline on the vermis and the extremities on the cerebellar hemispheres

deep cerebellar nuclei

• Dentate

  • Lateral hemisphere

• Interposed nucleus

  • Made up of emboliform and globose nuclei

  • In paravermal and vermal areas

• Fastigial Nucleus

  • Connected with flocculonodular lobe (and in vermis)

“don’t eat greasy food”

feedback mechanism

• The plan for movement is compared with the sensory, proprioceptive signals resulting from movement.

• Does NOT require learning.

• An accurate comparison between actual and planned movement.

• Slow and can only correct errors that have already occurred.

• Cannot predict and prevent errors.

feed-forward mechanism

• Allows quick reaction because errors are predicted AND prevented before they happen.

• A system based on learning from previous experiences, correcting ongoing movement before an error occurs.

• Functions for our own movements and movements of objects & people around us.

• Vestibulocerebellar Connections

• Afferents to the cerebellum provide information about the position of the head and body in space.

• Efferents from cerebellum adjust trunk stability and balance.

• Contains both feedback and feed-forward mechanisms

• Spinocerebellar Connections

• Comprises the anterior lobe, vermis, and superior paravermal area

• Input: proprioceptive input received from the spinocerebellar and cuneocerebellar tracts

• Functions: coordinates truncal movement and limb movement

• Cerebrocerebellar Connections

• Comprises the lateral aspects of the posterior lobes

• Reciprocal connections with cerebrum to streamline motor output from cortex

• Functions: hand-eye coordination, fine-tuning motor patterns, modulates language and cognition

afferent peduncle - superior

• Mossy fibers and Climbing fibers

• Ventral Spinocerebellar tract- lower extremity proprioceptive info into cerebellum

• Rostral Cerebellar Tract- cervical and upper extremity proprioceptive information

• Tectocerebellar tract- information from visual and auditory stimuli

superior- efferent pentacle

Middle cerebellar peduncle

• Afferent

  • Corticopontocerebellar fibers 

    • Cortex> Pons >Cerebellum

  • Communicates with Basal Ganglia

Afferent- inferior cerebellar peduncle

• Dorsal Spinocerebellar tract

• Cuneocerebellar tract

• Vestibulocerebellar Tract

• Olivocerebellar Tract

• Reticulocerebellar

efferent- inferior cerebellar peduncle

• Cerebelloraticular tract-  activates flexion or extension of body

• Cerebellovestibular tract- controls postural muscles, antigravity muscles, ocular muscles

• Superior cerebellar artery (SCA)

• Anterior lobe, superior part of vermis, superior third of posterior lobe

Anterior inferior cerebellar artery (AICA)

• Anterior surface of cerebellum and flocculonodular lobe

Posterior inferior cerebellar artery (PICA)

• Inferior ⅔ of posterior lobe and inferior part of vermis

Flocculonodular Lobe Syndrome

• Lesion to the Flocculonodular Lobe

• Truncal ataxia, wide stance, sway

• Potential for nystagmus

Anterior Lobe Syndrome

• Lesion to the Anterior Lobe

  • Can be caused by ethanol (alcohol)

• Gait ataxia, truncal ataxia, nystagmus

Posterior Lobe Syndrome

• Lesion to the Posterior Lobe

• Deficits in hand-eye coordination, dysmetria, dysdiadochokinesia, and linguistic incoordination