QS Study

The cerebrum is the part of the brain involved in the higher levels of thinking and action. It is involved in the control of voluntary and involuntary movement as well as balance. The cerebellum is located behind the top part of the brain stem and is made of two hemispheres.

Development of cerebellum: Cerebellar hemispheres develop by the proliferation of superior rhombic lip and adjacent dorsal part of the dorsolateral lamina of the metencephalon. Neural development beginnings quite early, therefore also look at notes covering Week 3- neural tube and Week 4-early nervous system.

Vermis: Develops by both ventrolateral and dorsolateral lamina.

Connections of the cerebellum: The fibres entering or leaving the cerebellum are grouped to form three peduncles:

(a) Inferior cerebellar peduncle – Connects with medulla (chiefly afferent).

  • Spino-cerebellar dorsal tract – a kinetic constituent of the proprioception from the ipsilateral lower limb
  • Bulbo-cerebellar tract – static constituent of the proprioception from all limbs
  • Cuneo-cerebellar tract – a kinetic constituent of the proprioception from upper limbs
  • Olivo-cerebellar tract – information about the current commands for execution of a motion, part of the control circuit
  • Reticulo-cerebellar tract – information about the intended movement modified from other structures (e.g. from the limbic system).

(b) Middle cerebellar peduncle – Connects with pons (chiefly afferent).

(c) Superior cerebellar peduncle – Connects with midbrain (Chiefly efferent).

  • Cerebello-thalamic tract – (about the body position) sent from the cerebellum to the cortex, before intended movement
  • Cerebello-rubral tract – information to the control cerebellar circuit and to the brain stem motor systems
  • Cerebello – reticular tract – information to the brainstem motor circuits
  • Spino-cerebellar ventral tract – a kinetic constituent of the proprioception from the contralateral lower limb.

Constituents of the cerebellar peduncles:

Afferent tracts are placed in all cerebellar peduncles, by which they reach all cerebellar parts (vestibule-, spino- and ponto- cerebellum). The largest inputs are the cortical inputs, interpolated in the pontine nuclei. They run through the middle cerebellar peduncles (brachia points).

Efferent tracts running to the thalamus, red nucleus and reticular formation nuclei are localized in the superior cerebellar peduncles (brachia conjunctiva). For more information look at the scheme.

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