Published on 03/03/2015 by admin
Filed under Neurology
Last modified 03/03/2015
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Chapter 12
BASIC ANATOMY
The deep cerebellar nuclei
The functional loops
The cerebrocerebellum
The vestibulocerebellum
The spinocerebellum
The olivocerebellum
Peduncles
Afferent connections
Efferent connections
The intrinsic circuitry within the cerebellum
FUNCTION OF THE CEREBELLUM
Cerebrocerebellum
Vestibulocerebellum
Spinocerebellum
The detail
The cerebellum, often refered to as the ‘little brain’, makes up only 10% of the total brain volume but contains more than 50% of the total number of neurons. It is composed of an outer layered cortical region and an inner subcortical mass of cells which form the deep cerebellar nuclei (DCN). The cerebellum is topographically arranged and has ipsilateral control of movement, that is, the left hemisphere of the cerebellum controls the left side of the body. The cerebellum is divided by two deep transverse fissures into three lobes, anterior, posterior and flocculonodular lobe. On the upper surface there are three functional regions separated anatomically by two longtitudinal stripes. The central vermis (medial zone) and two paravermal regions or hemispheres. The paravermal regions are divided into the lateral and intermediate zones.
There are four deep cerebellar nuclei (DCN):
• Fastigial
• Interposed – globose and emboliform
• Dentate
All output from the cerebellum leaves via the DCN, with the exception of output to the vestibular nuclei which has a direct connection. Afferent pathways also send collaterals that synapse on neurons in the DCN.
Based on its function, the cerebellum can be broadly divided into four loops:
This incorporates a loop between the cerebral cortex and the cerebellum. It is located in the lateral zone of the paravermal regions and is strongly connected with the dentate nucleus.
This incorporates a loop between the vestibular system and the cerebellum. It roughly corresponds to the flocculonodular lobe and has no connection to the DCN.
This incorporates a loop between the spinal cord and the cerebellum. It extends through the central vermis (medial zone) linked to the fastigial nucleus and the intermediate zone of the paravermal regions connected to the interposed nucleus.
This incorporates a loop between the inferior olivary nucleus (in the medulla oblongata) and the cerebellum. It has strong links to the DCN.
Neurological Assessment A Clinicians Guide
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