The Cerebellum Flashcards
where in the brain is the cerebellum?
an outgrowth of the rostral hindbrain
where does the cerebellum specifically arise from?
just caudal to midbrain:
isthmus and rhombomere 1
when does the cerebellum grow rapidly?
in the postnatal period
the developing cerebellum is small when?
at birth
what is the cerebellum central white matter shaped like?
the trunk of a tree
what do the white matter branches of the cerebellum form?
major lobules of the central cerebellum
in what type of section does the cerebellum look like a piece of cauliflower?
mid-sagittal section
what is the midline of the CB?
the vermis
what does the vermis consist of?
10 recognizable lobules in all mammals
the cerebral cortex relies on the CB for what?
movement coordination
the CC requests CB info via what?
the corticopontine pathway
where does the corticopontine tract travel to?
the rostral hindbrain
the pontine nuclei send axons to the CB of what side?
the opposite side
pontine nuclei send axons to CB via what?
the middle cerebellar peduncle
the CB responds to forebrain requests via what?
the superior cerebellar peduncle
where does the superior cerebellar peduncle travel to?
the opposite ventrolateral thalamic nucleus
the superior cerebellar peduncle travels to the ventrolateral thalamic nucleus of which side?
the opposite side
what carries SC and BS fibers on it’s way to the CB cortex.
the inferior cerebellar peduncle
what is the CB vermis of all mammals divided into?
10 lobules
what are the 10 lobules of the CB vermis divided by?
a series of deep fissures
what is the largest fissure in the CB vermis?
the primary fissure
what does the primary fissure divide?
the anterior vermis from the posterior vermis
what does the anterior vermis consist of?
lobules 1 - 5
what does the posterior vermis consist of?
lobules 6 - 10
what is the name of lobule 10?
the nodule
the human CB hemisphere is marked by 100s of what?
folia
what direction do folia run?
medial to lateral
what is the center of the CB filled with?
the deep CB white matter
what is in the deep CB white matter?
3 deep CB nuclei on either side
what is the largest deep CB nuclei?
the dentate nucleus
where is the dentate nucleus placed?
laterally
the CB is connected to the hindbrain via:
3 CB peduncles on either side
what does inferior CB peduncle contain?
fibers entering CB from SC and inferior olive
what does middle CB peduncle contain?
fibers entering CB from basilar pons
what does the superior CB peduncle contain?
fibers that leave CB to travel through the red nucleus to reach the thalamus
each cerebral cortex is connected to sensory and motor activities on what side of the body?
the opposite side
each CB side is connected to which body side?
the ipsilateral/same side
when one CB hemisphere is damaged, what are the classic symptoms?
incoordination of voluntary movement and tremor on the ipsilateral side.
how many CB cortex layers are there?
3
what are the CB cortex layers?
outer molecular layer
the Purkinje cell layer
the inner granule cell layer
what is in the deep to the granule cell layer?
the deep CB white matter
what parts of the CB cortex are uniform?
the layers
the relative thickness of each layer
what is in the deep to the CB cortex?
the deep CB white matter
what are the output cells of the CB cortex?
the Purkinje cells
where do the axons of the Purkinje cells project to?
to the CB nuclei
most fibers projecting to the CB cortex are:
mossy fibers
what do mossy fibers that project to the CB cortex synapse with?
granule cells
what exceptions do not have mossy fibers that project to the cerebral cortex?
inferior olive input
where does inferior olive input directly go to in the CB?
dendritic trees of Purkinje cells
inferior olive inputs go to the dendritic trees of Purkinje cells in the form of:
climbing fibers
where do mossy fibers arise from?
the pontine nuclei cells & other large pre-cerebellar nuclei in the hindbrain and from the SC.
granule cells send their axons to:
the dendritic spines of Purkinje cells
granule cells comprise what percentage of neurons in the brain?
70%
granule cells are tiny and tightly packed; their density in the cerebellum is:
1 million per cubic millimeter
there is evidence that inferior olivary cells control what in the CB?
the time code of the CB
what does the time code that the inferior olivary cells send to the CB ensure?
that learned movement is played back in the right timing sequence
at what rate do inferior olivary cells fire the time code to the CB?
10Hz (10 APs per second)
rat microelectrode recordings suggest that every folium in the CB codes a different:
movement sequence
what are movement sequence examples the folium in the CB could encode?
taking food with the fingers and transferring it to the mouth
running behaviour
given that there are 10,000s of folium in the CB, it is possible that the CB:
keeps learning new movement sequences in adult life
the largest human CB connection is with what?
the motor cortex
what is the journey of the corticopontine pathway?
arises from the CC
synapses in the pons
enters the CB as the middle CB peduncle
the middle CB peduncle is a way for the motor cortex to:
ask the CB for help when complex movement is required
the answer regarding complex movements is returned to the motor cortex via:
the superior CB peduncle
where do the fibers of the superior CB peduncle synapse?
in the ventrolateral nucleus of the thalamus
thalamocortical fibers travel to where?
the motor cortex
the ratio of the number of CB cells to the number of CC cells in the human brain is:
4:1 respectively
what is the main way that the CB tracks limb movement?
through sensation from the skin
it appears that most input in the CB for tracking movement comes from:
receptors that detect sensations of stretching, contact and/or folding in the skin
what do the skin sensations inputted to the CB provide fine detail on?
movement of the limbs and other body parts
