Cerebellum: Anatomy and Function

Introduction

• Overview of cerebellum anatomy and function.
• Focus on anatomical and functional views, internal circuitry, and associated pathways.

General Anatomy

• Location: Posterior cranial fossa of the skull, separated from the cerebrum by the tentorium cerebelli.
• Folia: Small folds to increase surface area.
• Gray Matter (Outer): Unmyelinated cell bodies or dendrites.
• White Matter (Inner): Arbor vitae (tree of life), myelinated axons connecting the cerebellum to the brainstem.

Fissures and Lobes

• Primary Fissure: Separates the anterior and posterior lobes.
• Posterior Lateral Fissure: Separates the posterior and flocculonodular lobes.
• Lobes:
  • Anterior Lobe
  • Posterior Lobe
  • Flocculonodular Lobe

Functions of the Cerebellum

• Balance and Equilibrium: Connects with the inner ear, vestibular cerebellar tract.
• Muscle Tone: Influenced by proprioceptors, Golgi tendon organs, muscle spindles, and joint capsules.
• Coordination of Movement: Involves motor planning and interaction with cerebral cortex and basal ganglia.
• Motor Learning: Refinement and adaptation of motor skills.

Anatomical and Functional Zones

• Anterior Lobe (Spinocerebellum):
  • Occupies the vermal and paravermal (intermediate) zones.
  • Receives sensory information from trunk and extremities.
• Posterior Lobe (Cerebrocerebellum):
  • Located in the lateral hemispheres.
  • Associated with motor planning and coordination with the cerebrum.
• Flocculonodular Lobe (Vestibular Cerebellum):
  • Primitive part, linked with vestibular functions.

Deep Cerebellar Nuclei

• Mnemonic: Don't Eat Greasy Food
  • Dentate Nucleus: Lateral Hemisphere (Cerebrocerebellum)
  • Interposed Nucleus: Contains Emboliform and Globose nuclei (Spinocerebellum)
  • Fastigial Nucleus: Flocculonodular Lobe (Vestibular Cerebellum)

Internal Circuitry

• Layers of Cerebellar Cortex:
  • Molecular Layer
  • Purkinje Layer
  • Granular Layer
• Fibers:
  • Climbing Fibers: From inferior olives, stimulate Purkinje cells.
  • Mossy Fibers: From sensory pathways, interact with granule cells and Golgi cells.
• Neural Sharpening: Ensures precise and coordinated neural output.

Pathways Associated with Cerebellum

• Superior Cerebellar Peduncles:
  • Efferent: Dentothalamic, Dentorubrothalamic pathways.
  • Afferent: Ventral spinocerebellar, rostral cerebellar, tectocerebellar tracts.
• Middle Cerebellar Peduncles:
  • Afferent: Corticopontocerebellar fibers.
• Inferior Cerebellar Peduncles:
  • Afferent: Dorsal spinocerebellar, cuneocerebellar, vestibular, oliveocerebellar, reticulocerebellar pathways.
  • Efferent: Cerebelloreticular, cerebellovestibular pathways.

Conclusion

• Summary of the cerebellum's role in balance, muscle tone, coordination, and motor learning.
• Importance of cerebellar pathways in integrating sensory and motor information.