Transcript Neuro 09 Cerebellum Student

CEREBELLUM
Gross Morphology
Tentorium cerebelli
 Falx cerebelli

Anatomical Plan I

Left and right hemispheres:
Anterior and posterior lobe:
Subconscious movements of skeletal
muscles
Flocculonodular nodes:
Concerned with equilibrium

Vermis
Anatomical Divisions

Cerebellar cortex:
Gyri = Folia

Myelinated medulla:
Arbor vitae
Cerebellar Peduncles

Inferior (restiform bodies):
Connects to medulla

Middle (brachium pontis):
Connects to pons

Superior (brachium conjunctivum):
Connects to midbrain and thalamus
Nuclei

Intracerebellar (paired):
Dentate
Emboliform
Globose
Fastigial
Pontine nuclei (pons):
 Inferior olivary nuclei (medulla)

Plan II: Flocculonodular Lobes
Archicerebellum
 Vestibulocerebellum
 Flocculi separated by nodulus
 Functions:

Regulation of muscle tone
Maintenance of equilibrium (axial
musculature)
Regulation of head/eye movements
Plan II: Anterior Lobe
Paleocerebellum
 Functions:

Receives proprioceptive information
Regulates muscle tone
Plan II: Posterior Lobe
Neocerebellum
 Cerebrocerebellum
 Functions:

Receives cerebral input via pons
Involved in muscle movement
Involved in planning and coordination
Anatomical Plan III

Medial (vermal) zone:
Fastigial nucleus
Part of spinocerebellum

Paramedian (paravermal) zone:
Globose and emboliform nuclei
Part of spinocerebellum

Lateral (hemispheric) zone:
Dentate nucleus
Equivalent to neocerebellum (cerebrocerebellum)
Afferent: Mossy Fibers

Via inferior cerebellar peduncles:
Dorsal spinocerebellar
Reticulocerebellar

Via superior cerebellar peduncles:
Ventral spinocerebellar

Via middle cerebellar peduncles:
Pontocerebellar
Afferent: Climbing Fibers

Climbing fibers arise from inferior olivary
nuclei
Efferent Tracts
All efferent fibers from cortex are from
Purkinje cells:
 Purkinje cells project to intracerebellar
nuclei.

Efferent Tracts

Via inferior cerebellar peduncles:
To vestibular nuclei:
Cerebellovestibular:
From flocculonodular lobe
= (vestibulocerebellum)
From fastigial nucleus
To lateral vestibular nucleus:
Cerebellovestibular
From anterior vermis (spinocerebellum)
Efferent Tracts

Via inferior cerebellar peduncles:
To reticular formations in pons and medulla:
Cerebelloreticular tract:
From fastigial nucleus
Efferent Tracts

Via superior cerebellar peduncles:
To red nucleus (nucleus ruber):
Cerebellorubral tract:
From dentate, emboliform, and globose nuclei
To ventral anterior and ventral lateral
thalamic nuclei:
Cerebellothalamic tracts:
From dentate, emboliform, and globose nuclei
Efferent Tracts

Thalamocortical tracts:
To motor cortex
Through internal capsule

Corticopontine tracts:
To pontine nuclei
Functions
Skeletal muscle coordination
 Maintain equilibrium and posture
 Synergic control of muscle activity
 Kinetic memory?

Cerebellar Cortex: Layers

Molecular layer (outer)

Granular layer (middle)

Purkinje layer (deeper)
Cerebellar Cortex: Cell Types
Stellate cells
 Basket cells
 Granular cells
 Golgi cells
 Purkinje cells

Cerebellar Cortex Organization

Climbing and mossy fibers convey
excitatory input from spinal cord and
brainstem to deep cerebellar nuclei and
cortex.
Cerebellar Cortex Organization

Climbing fibers originate from inferior
olivary nuclei and are excitatory to deep
cerebellar nuclei and Purkinje cells.
Cerebellar Cortex Organization

Mossy fibers originate from spinal cord
and other parts of the brain and are
excitatory to granular cells.
Granular Cells

Granular cells receive input from mossy
fibers:
Excitatory input.
Collaterals from mossy fibers also to
intracerebellar nuclei.

Granular cells project into molecular layer
and give off left/right axon collaterals.
Granular Cells
Granular cells are excitatory.
 Synapse with:

Stellate, Golgi, basket, and Purkinje cells
Other Cortical Cells
Stellate cells synapse with dendritic tree of
Purkinje cells (inhibitory).
 Basket cells synapse with axon hillock of
Purkinje cell (inhibitory).
 Golgi cells synapse with cell bodies of
granular cells (inhibitory).
 Purkinje cells synapse with intracerebellar
nuclei (inhibitory).

Cerebellar Cortex

Climbing fibers from inferior olivary nuclei:
Synapse with intracerebellar nuclei:
Axon collaterals
Excitatory
Synapse with dendritic tree of Purkinje cells:
Excitatory
Excitatory burst “cleans” Purkinje cells
Cerebellar Cortex
Only efferents from cerebellar cortex are
Purkinje cell axons.
 All efferents from cerebellum are from
intracerebellar nuclei.

Cerebellar Cortex
Noradrenergic projections from locus
ceruleus.
 Serotoninergic projections from raphe
nuclei.
