Lecture on the Cerebellum

Introduction

• Focus on the cerebellum's anatomy and function.
• Three main views: anatomical lateral view, posterior view, and a slice to view internal circuitry.
• Location: posterior cranial fossa of the skull.
• Separated from the cerebrum by tentorium cerebelli.

Anatomy of the Cerebellum

External Structure

• Folia: folds that increase surface area.
• Outer Grey Matter: contains unmyelinated cell bodies/dendrites.
• Arbor Vitae (Tree of Life): myelinated axons connecting cerebellum to brainstem.
• Fissures:
  • Primary Fissure
  • Posterior Lateral Fissure
• Lobes:
  • Anterior Lobe
  • Posterior Lobe
  • Flocculonodular Lobe (primitive section)

Internal Structure

• Deep Cerebellar Nuclei:
  • Dentate Nucleus
  • Emboliform Nucleus
  • Globose Nucleus
  • Fastigial Nucleus

Functions of the Cerebellum

• Balance and Equilibrium: connected with the inner ear.
• Muscle Tone: influenced by proprioceptors like Golgi tendon organs, muscle spindles.
• Coordination of Movement
• Motor Learning

Functional Zones

• Spinocerebellum: Anterior lobe, Vermis, and Paravermal Zone.
• Cerebrocerebellum: Posterior lobe, lateral hemispheres.
• Vestibulocerebellum: Flocculonodular lobe.

Internal Circuitry

• Layers of the Cerebellar Cortex:
  • Molecular Layer
  • Purkinje Layer
  • Granular Layer
• Circuit Pathways:
  • Climbing Fibers (from Inferior Olives)
  • Mossy Fibers (from various sensory pathways)

Pathways

Superior Cerebellar Peduncles

• Efferent Connections: Dentate to thalamus and red nucleus.
  • Dento-Thalamic Pathway
  • Rubrospinal Pathway
• Afferent Connections: Ventral Spinocerebellar Tract, Rostral Cerebellar Tract.

Middle Cerebellar Peduncles

• Corticopontocerebellar Pathway: connects motor plans from cortex to cerebellum.

Inferior Cerebellar Peduncles

• Afferent Pathways:

  • Dorsal Spinocerebellar Tract
  • Cuneocerebellar Tract
  • Vestibulocerebellar Tract
  • Olivocerebellar Tract
  • Reticulocerebellar Pathway

• Efferent Pathways:

  • Cerebellar Vestibular Pathway
  • Cerebellar Reticular Pathway

Conclusion

• The cerebellum integrates sensory information and motor plans to coordinate movement, maintain balance, and facilitate motor learning.
• Importance of understanding cerebellar pathways for comprehending its role in the nervous system.