Neurosurgery notes/Anatomy/Cerebellum/Cerebellar function

Cerebellar function

View Details
Status
Done
logo
Parent item
Cerebellum

List of function

  • Control of movement
    • Modifies movements produced by stimulation of motor areas of the cerebral cortex.
  • Learning of movements
    • (For example, in learning to write).
  • Maintaining the equilibrium of the body
    • Through its vestibular and spinal connections
    • By receiving
      • Proprioceptive information from joints
        • Muscle contraction
        • Joint position
      • Eyes
      • Ears
      • Vestibular apparatus
      • Reticular formation
      • Cerebral cortex
  • Localization of function
      • There is a double representation
      • One on the Anterior lobe
        • Representation on the anterior lobe is ipsilateral
      • One on the posterior lobe
        • Representation on the posterior lobe is bilateral
      • On either surface, the anteroposterior sequence of parts represented is leg, trunk, arm and head.
      • These areas are located in vermal and paravermal areas (paleocerebellum)
      • Correspond to areas that receive fibres from the spinal cord.
      • Stimulation of these areas produces movements in parts of the body that correspond roughly to those from which sensory impulses are received
      notion image
      notion image
      notion image
      notion image

Functional Anatomic Organization of Cerebellum

Vestibulocerebellum

  • Consists of the flocculonodular lobe.
  • Afferent
    • Mossy fibers from the ipsilateral vestibular nuclei + vestibular ganglion via the inferior cerebellar peduncles.
    • Visual information from the
      • Lateral geniculate nucleus
      • Superior colliculi
      • Striate cortex
  • Efferent
    • Purkinje cell axons project to the fastigial nucleus → fastigial nucleus axons leave the cerebellum via inferior cerebellar peduncles → vestibular nuclei → Vestibulospinal tract.
  • Function
    • Adjustment of axial muscle tone
    • Maintenance of equilibrium
    • Plays a role in eye movements, control, and the coordination of head and eye movements.
image

Spinocerebellum

  • Consists of the vermis and the intermediate part of the cerebellar hemispheres.
  • Afferent
    • Dorsal and ventral spinocerebellar tracts (somatosensory information) of the spinal cord.
    • Auditory, visual, and vestibular systems.
  • Efferent
    • Purkinje cells of the vermis → send axons to the fastigial nucleus →
      • Fastigial axons project to the
        • Brainstem reticular formation
        • Brainstem lateral vestibular nuclei,
        • Ventrolateral thalamus → Primary motor cortex
      • Function control of the medial descending systems, which regulate axial and proximal musculature.
    • Purkinje cells in the intermediate part of the cerebellar hemispheres send axons →
      • Interposed nuclei sends axon →
        • (Decussate at) Superior cerebellar peduncle → to the rubrospinal and lateral corticospinal tracts (decussate at caudal medulla).
        • To ventrolateral thalamus → primary motor cortex.
      • Function
        • Control of the lateral descending systems, which regulate the distal limb muscles.
          • Destructive lesions in the intermediate zone of the cerebellar hemispheres result in neurologic deficits on the ipsilateral side of the body: the spinocerebellum influences the skeletal musculature on the ipsilateral side of the body.
        • Controls the execution of movement and regulates muscle tone.
          • It carries out these functions by continuously comparing information about the intended motor commands of the primary motor cortex with feedback about ongoing movement that is received from the spinal cord and periphery.
          • This organization allows the spinocerebellum to correct for deviations in intended movement.
      • Pathology
        • Pass pointing
image

Pontocerebellum

  • Consists of the large lateral regions of the cerebellar hemispheres.
  • Afferent
    • Large areas of the contralateral cerebral cortex (especially that of the frontal and parietal lobes) → Corticopontine fibers → Pontine nuclei → middle cerebellar peduncles (sole/main constituents of middle cerebellar peduncle)
    • The information that is transmitted from the cerebral cortex to the cerebellum concerns volitional movements that are ongoing or are about to happen.
  • Efferent
    • Corticopontine-thalamic-cortical loop: Purkinje cell axons of cerebellar cortex → dentate nucleus → superior cerebellar peduncles (decussate/Pontocerebellar efferents make up most of the fibers in the superior cerebellar peduncles) → ventro-lateral nucleus of the thalamus → primary motor cortex → Corticospinal tract (decussate at caudal medulla)
      • Because of decussations in both the superior cerebellar peduncles and the corticospinal tract and other descending pathways, the pontocerebellum exerts its influence on the ipsilateral side of the body.
  • Function
    • Precision in the control of rapid limb movements
    • Tasks requiring fine dexterity.
      • It ensures a smooth and orderly sequence in muscle contractions and regulates the force, direction, and extent of volitional movement.
      • It functions in these capacities by modulating activity in the primary motor cortex, a role that is also performed by the premotor cortical areas.
  • Pathology
    • Destructive lesions in the pontocerebellum may lead to various movement disorders, such as delays in the initiation or termination of movement, or involuntary tremor at the end of a movement.
image