Cerebellum Flashcards
What is unique about the size of the cerebellum?
small in size but very high in neuron density
- 80% of brain total neurons, only 10% of its size
What is the sensory function of the cerebellum?
subconscious proprioception (unconscious): tone and posture
What is the general anatomy of the cerebellum? Where is are the white and gray matter?
- outer gray matter (folia)
- inner white matter tracts (arborvitae)
What are the three lobes of the cerebellum?
- flocculonodular (lowest and smallest lobe)
- anterior
- posterior
What structures connect the cerebellum to the spinal cord?
three pairs of cerebral peduncles
- inferior
- middle
- superior
What information does the inferior peduncle transmit?
afferent info from the spinal cord and brainstem to the cerebellum
What information does the middle peduncle transmit?
afferent info from the pontine nuclei in the pons
What information does the superior peduncle transmit?
- mostly efferent info from the cerebellum to the thalamus and brainstem
- also afferent info from the midbrain
What are the 3 layers of the cerebellum?
- molecular (thick)
- purkinje (cell bodies of purkinje neurons here which are inhibited by GABA
- granular
after the granular layer you see white tracts
What type of brain matter makes up the molecular layer of the cerebellum?
gray matter
What nuclei is the most numerous output nuclei of the cerebellum?
purkinje neurons
What nuclei are the main source of cerebellar input?
- mossy fiber
- climbing fiber
Are mossy fibers and climbing fibers excitatory or inhibitory?
excitatory
Where do mossy fibers originate?
vestibular nuclei, spinal cord, and cerebral cortex
Where do climbing fibers originate?
contralateral inferior olivary nucleus
What movement are climbing fibers important for creating?
smooth movement
What does the inferior olivary nucleus do?
helps with motor coordination and motor learning through afferent signal it brings to the nucleus
What is the net effect of purkinje fibers and what do they do?
- net effect is inhibitory
- helps shape and smooth movement
What is the route of mossy fibers in the cerebellum?
mossy fiber > cerebellar white matter > granular cell in cerebellar cortex > purkinje cell > output
What is the route of climbing fibers in the cerebellum?
climbing fiber > cerebellar white matter > wraps around and synapses on purkinje cell > efferent output signal
What are input and output fibers of the cerebellum?
input: climbing and mossy fibers
output: purkinje cells and deep cerebellar nuclei
What are the four deep cerebellar nuclei?
- fastigal nuclei
- globose nucleus
- emboliform nuclei
- dentate nuclei
Which deep cerebellar nuclei belong to the nucleus interpositus?
- globose nucleus
- emoboliform nuclei
What role is associated with the fastigal nuclei?
- balance