Cerebellum Flashcards
Where is the cerebellum found?
Posterior cranial fossa
What is the name given to the part of the cerebellum that lies along the midline?
Vermis
What divides the vermis and more lateral parts of the cerebellum into the anterior and posterior lobe?
Primary fissure
What is the flocculus? What does it help form?
Small lobe of the cerebellum at the posterior border of the middle cerebellar peduncle
Forms part of the roof of the 4th ventricle (flocculonodular lobe)
Describe the main blood supply to the cerebellum.
Supplied by 3 main arteries:
- Superior cerebellar artery
- Anterior inferior cerebellar artery
- Posterior inferior cerebellar artery (most common site of an infarct in the posterior circulation)
Describe the microanatomy of the cerebellum. (3 distinct layers; what is found in each)
- Outer molecular layer: pale with mostly axons and only a few cells
- Middle layer: single row of Purkinje cells
- Inner layer: granule layer - thick and contains vast numbers of granule cells
Where are the cerebellar input fibres located?
Middle cerebellar peduncle - input fibres from the contralateral cerebral cortex and cranial nerves
Inferior cerebellar peduncle - input fibres from the spinal cord
Where are the cerebellar output fibres located?
Superior cerebellar peduncle
Describe the course of the dorsal/posterior spinocerebellar tract in the body.
This is a column of relay neuron cell bodies within the medial gray matter within the spinal cord in layer VII, specifically between T1-L3
- These neurons then send axons up the spinal cord
- Project ipsilaterally to medial zones of the cerebellum through the inferior cerebellar peduncle
Carries information from proprioceptors (joints, muscle spindles, golgi apparatus)
Describe the course of the ventral/anterior spinocerebellar tract in the body.
- Some neurons of the ventral spinocerebellar tract form synapses with neurons in layer VII of L4-S3
- Most of these fibres cross over to the contralateral lateral funiculus via the anterior white commissure and through the superior cerebellar peduncle
- The fibres then often cross over again within the cerebellum to end on the ipsilateral side. (globose and emboliform nuclei)
- -> tract is sometimes termed the “double-crosser.”
Carries information about the state of reflexes in the spinal cord
(cerebellar signs are always on the same side as the lesion)
What are the deep cerebellar nuclei?
nuclei that lie in the white matter below the cortex through which all input/output to the cerebellar cortex pass
medial -> lateral: Fastigial nucleus; Globose nucleus; Emboliform nucleus; Dentate nucleus
Which parts of the cerebellar cortex are connected to each deep cerebellar nucleus?
Vermis -> Fastigial nucleus
Anterior lobe -> Globose and Emboliform nuclei
Hemispheres -> Dentate nucleus
(Flocculonodular connects to the lateral vestibular nuclei of the pons)
What is the role of the cerebellum in relation to movement?
Helps the motor cortex produce accurate and smooth movements
- modulates + refines motor cortex commands
What are signs of cerebellar damage?
Clumsiness
Abnormal fatigue
Instability
*extraocular eye msucles are particularly affected
What would happen if the deep nuclei were damaged?
Usually the cerebellum exhibits neuronal plasticity meaning that recovery after damage is possible
However, if the deep nuclei are damaged then there will be persistent disability