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331 Cards in this Set
- Front
- Back
|
What does the cerebellum fine coordinate?
|
movement and balance
|
|
|
Where does the cerebellum receive its input
|
spinal cord - position of the body with respect to space and time (sensory)
|
|
|
Function of cerebellum
|
compares sensory and goal information to calculate the sequence of muscle contractions (tactics), required to achieve the goal
|
|
|
Cerebellum facts
|
- constitues 10% of the brain volume but contains more than half of the entire neuronal population
|
|
|
Development of the cerebellum
|
- originates from the most rostral segment of the metencephalon (rhombomere 1)
|
|
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Rhombic lips
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- lateral growth of rhombomere 1
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|
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Cerebellar neurons origin
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Two different germinal matrices:
|
|
|
Ventricular germinal matrix
|
progenitors near the ventricle (ventricular zone) in the cerebellar primordia migrate vertically/laterally to generate neurons of the 1. deep cerebellar nuclei, 2. Purkinje cells and 3. interneurons
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|
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Specialized germinal matrix
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- progenitors in the rhombic lips, migrate radially over the surface of the cerebellar primordia to form the outer granular layer
|
|
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Molecular layer
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- outler layering underlying the pia
|
|
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Cerebellum attachments to brainstem
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1. inferior cerebellar peduncles (restiform body) - afferent sensory information about position of body in space from SC; also carries efferent info from vermis to brain stems
|
|
|
inferior cerebellar peduncles (restiform body)
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- afferent sensory information about position of body in space (dorsal spinocerebellar, cuneocerebellar and olivocerebellar tract - from contralateral inferior olivary nucleus)
|
|
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middle cerebellar peduncles (branchium pontis)
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- afferent information from pontocerebellar fibers to neocerebellum (pontocerebellum) about intended goals from the cerebral cortex
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|
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superior cerebellar peduncles (branchium conjunctivum)
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- efferent feedback to midbrain and thalamus (dentatothalamic tract - terminates in ventral lateral nucleus of the thalamus)
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|
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Cerebellum organization
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1. outer cerebellar cortex
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|
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Pairs of deep cerebellar nuclei
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arranged on each side of the midline - that send projections out to each specific mediolateral subdivision of the cerebral cortex
|
|
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Fastigial nuclei
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- output from the vermis
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|
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Interposed nuclei
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- globose + emboliform
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Dentate nucleus
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- output from lateral lobe
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Flocculonodular lobe
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- does NOT have a deep cerebellar nuclei
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Rostrocaudal subdivision (phyllogenetic subdivision) of cerebellum
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- divided by transverse fissures = folia
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primary fissure
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separates anterior lobe from posterior lobe
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posterolateral fissure
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separates posterior lobe from flocculonodular lobe
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anterior lobe
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- most evolved portion
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posterior lobe
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- next most recent evolved (after anterior)
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flocculonodular lobe
|
- oldest, most primitive lobe
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|
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lobules
|
additional shallow fissures divide each lobe into smaller groups (9)
|
|
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Mediolateral subdivision (functional subdivision)
|
- divided mediolaterally by two longitudinal fissures
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|
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Spinocerebellum
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- 1. vermis + 2. intermediate hemisphere
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Cerebrocerebellum (lateral hemisphere)
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- lateral lobe
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|
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Vestibulocerebellum
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- flocculonodular lobe
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|
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Cellular organization in the cerebellar cortex
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- 5 neuronal cell types arranged in 3 layers:
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|
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Purkinje cell layer
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- middle layer of cerebellar cortex
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|
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Granule cell layer
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- deepest layer of the cerebellar cortex
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|
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Granule cells
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- excite (via glutamate) 1. Purkinje 2. basket 3. stellate 4. Golgi II cells through parallel fibers
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|
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Parallel fibers
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- unmyelinated axons of the granule cells
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|
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Mossy fibers
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- afferent excitatory fibers of the 1. spinocerebellar 2. pontocerebellar and 3. vestibulocerebellar tracts
|
|
|
Climbing fibers
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- afferent excitatory (via aspartate) fibers of olivocerebellar tract
|
|
|
Granule cell: Purkinje cell ratio
|
the evolution of the cerebellar cortex that correlates with the acquisition of dexterity and the manipulative abilities in humans
|
|
|
Excitation of Purkinje cells
|
- main output neurons of the cerebellar cortex (Purkinje cells) are excited by climbing fibers and Mossy fibers (via the parallel fibers of granule cells
|
|
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Functional circuitry
|
- excited Purkinje cells inhibit spontaneously active deep cerebellar nuclei (excitatory collaterals from the climbing and Mossy fibers set the threshold for the inhibition of the deep cerebellar nuclei neurons)
|
|
|
Center-surround inhibition
|
- Excitation of the narrow beam of parallel fibers excites an array of Purkinje cells and basket cells
|
|
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What
|
does
|
|
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Where
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does
|
|
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pons
|
-
|
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Function
|
of
|
|
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Cerebellum
|
facts -
|
|
|
-
|
one
|
|
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Development
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of
|
|
|
-
|
from
|
|
|
-
|
further
|
|
|
-
|
cells
|
|
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Rhombic
|
lips -
|
|
|
-
|
grow
|
|
|
Cerebellar
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neurons
|
|
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1.
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Ventricular
|
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2.
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Specialized
|
|
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Ventricular
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germinal
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|
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Specialized
|
germinal
|
|
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-
|
progenitors
|
|
|
-
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migration
|
|
|
Molecular
|
layer -
|
|
|
-
|
contains
|
|
|
-
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stellate
|
|
|
-transversed
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by
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Cerebellum
|
attachments
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2.
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middle
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3.
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superior
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inferior
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cerebellar
|
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-
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also
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middle
|
cerebellar
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superior
|
cerebellar
|
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-
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dentatothalamic
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-
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afferent
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Cerebellum
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organization 1.
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|
|
2.
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inner
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|
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3.
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deep
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Pairs
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of
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Medial
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to
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1.
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fastigial
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2.
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interposed
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3.
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dentate
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*
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flocculonodular
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Fastigial
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nuclei -
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|
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-
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to
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|
|
-
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most
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Interposed
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nuclei -
|
|
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-
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output
|
|
|
-
|
to
|
|
|
-
|
lie
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|
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Dentate
|
nucleus -
|
|
|
-
|
to
|
|
|
-
|
gives
|
|
|
-
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decussation
|
|
|
Flocculonodular
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lobe -
|
|
|
-
|
projects
|
|
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Rostrocaudal
|
subdivision
|
|
|
-
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2
|
|
|
-
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primary
|
|
|
-
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posterolateral
|
|
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primary
|
fissure separates
|
|
|
posterolateral
|
fissure separates
|
|
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anterior
|
lobe -
|
|
|
-
|
coordination
|
|
|
-
|
1.
|
|
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posterior
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lobe -
|
|
|
-
|
control
|
|
|
-
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1.
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|
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flocculonodular
|
lobe -
|
|
|
-
|
maintenance
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|
|
-
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1.
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lobules additional
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shallow
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|
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1.
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central
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Mediolateral
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subdivision
|
|
|
-
|
central
|
|
|
-
|
each
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|
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Spinocerebellum -
|
1.
|
|
|
-
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fastigial
|
|
|
-
|
receive
|
|
|
-
|
output
|
|
|
Cerebrocerebellum
|
(lateral
|
|
|
-
|
receives
|
|
|
-
|
has
|
|
|
Vestibulocerebellum -
|
flocculonodular
|
|
|
-
|
afferents
|
|
|
-
|
no
|
|
|
Cellular
|
organization
|
|
|
1.
|
Molecular
|
|
|
2.
|
Purkinje
|
|
|
3.
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Granule
|
|
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Purkinje
|
cell
|
|
|
-
|
Purkinje
|
|
|
-
|
Purkinje
|
|
|
-
|
dendritic
|
|
|
-
|
parallel
|
|
|
-
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climbing
|
|
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Granule
|
cell
|
|
|
-
|
consists
|
|
|
-
|
granule
|
|
|
-
|
axons
|
|
|
-
|
parallel
|
|
|
Granule
|
cells -
|
|
|
-
|
inhibited
|
|
|
Parallel
|
fibers -
|
|
|
-
|
extend
|
|
|
Mossy
|
fibers -
|
|
|
-
|
from
|
|
|
-
|
terminate
|
|
|
-
|
excite
|
|
|
Climbing
|
fibers -
|
|
|
-
|
fibers
|
|
|
-
|
terminate
|
|
|
Granule
|
cell:
|
|
|
Excitation
|
of
|
|
|
-
|
regulated
|
|
|
-
|
Basket
|
|
|
-
|
Excitation
|
|
|
-
|
Excitation
|
|
|
Functional
|
circuitry -
|
|
|
-
|
Excitation
|
|
|
Center-surround
|
inhibition -
|
|
|
-
|
Excitation
|
|
|
Question
|
Answer
|
|
|
What does the cerebellum fine coordinate?
|
movement and balance
|
|
|
Where does the cerebellum receive its input
|
spinal cord - position of the body with respect to space and time (sensory)
|
|
|
Function of cerebellum
|
compares sensory and goal information to calculate the sequence of muscle contractions (tactics), required to achieve the goal
|
|
|
Cerebellum facts
|
- constitues 10% of the brain volume but contains more than half of the entire neuronal population
|
|
|
Development of the cerebellum
|
- originates from the most rostral segment of the metencephalon (rhombomere 1)
|
|
|
Rhombic lips
|
- lateral growth of rhombomere 1
|
|
|
Cerebellar neurons origin
|
Two different germinal matrices:
|
|
|
Ventricular germinal matrix
|
progenitors near the ventricle (ventricular zone) in the cerebellar primordia migrate vertically/laterally to generate neurons of the 1. deep cerebellar nuclei, 2. Purkinje cells and 3. interneurons
|
|
|
Specialized germinal matrix
|
- progenitors in the rhombic lips, migrate radially over the surface of the cerebellar primordia to form the outer granular layer
|
|
|
Molecular layer
|
- outler layering underlying the pia
|
|
|
Cerebellum attachments to brainstem
|
1. inferior cerebellar peduncles (restiform body) - afferent sensory information about position of body in space from SC; also carries efferent info from vermis to brain stems
|
|
|
inferior cerebellar peduncles (restiform body)
|
- afferent sensory information about position of body in space (dorsal spinocerebellar, cuneocerebellar and olivocerebellar tract - from contralateral inferior olivary nucleus)
|
|
|
middle cerebellar peduncles (branchium pontis)
|
- afferent information from pontocerebellar fibers to neocerebellum (pontocerebellum) about intended goals from the cerebral cortex
|
|
|
superior cerebellar peduncles (branchium conjunctivum)
|
- efferent feedback to midbrain and thalamus (dentatothalamic tract - terminates in ventral lateral nucleus of the thalamus)
|
|
|
Cerebellum organization
|
1. outer cerebellar cortex
|
|
|
Pairs of deep cerebellar nuclei
|
arranged on each side of the midline - that send projections out to each specific mediolateral subdivision of the cerebral cortex
|
|
|
Fastigial nuclei
|
- output from the vermis
|
|
|
Interposed nuclei
|
- globose + emboliform
|
|
|
Dentate nucleus
|
- output from lateral lobe
|
|
|
Flocculonodular lobe
|
- does NOT have a deep cerebellar nuclei
|
|
|
Rostrocaudal subdivision (phyllogenetic subdivision) of cerebellum
|
- divided by transverse fissures = folia
|
|
|
primary fissure
|
separates anterior lobe from posterior lobe
|
|
|
posterolateral fissure
|
separates posterior lobe from flocculonodular lobe
|
|
|
anterior lobe
|
- most evolved portion
|
|
|
posterior lobe
|
- next most recent evolved (after anterior)
|
|
|
flocculonodular lobe
|
- oldest, most primitive lobe
|
|
|
lobules
|
additional shallow fissures divide each lobe into smaller groups (9)
|
|
|
Mediolateral subdivision (functional subdivision)
|
- divided mediolaterally by two longitudinal fissures
|
|
|
Spinocerebellum
|
- 1. vermis + 2. intermediate hemisphere
|
|
|
Cerebrocerebellum (lateral hemisphere)
|
- lateral lobe
|
|
|
Vestibulocerebellum
|
- flocculonodular lobe
|
|
|
Cellular organization in the cerebellar cortex
|
- 5 neuronal cell types arranged in 3 layers:
|
|
|
Purkinje cell layer
|
- middle layer of cerebellar cortex
|
|
|
Granule cell layer
|
- deepest layer of the cerebellar cortex
|
|
|
Granule cells
|
- excite (via glutamate) 1. Purkinje 2. basket 3. stellate 4. Golgi II cells through parallel fibers
|
|
|
Parallel fibers
|
- unmyelinated axons of the granule cells
|
|
|
Mossy fibers
|
- afferent excitatory fibers of the 1. spinocerebellar 2. pontocerebellar and 3. vestibulocerebellar tracts
|
|
|
Climbing fibers
|
- afferent excitatory (via aspartate) fibers of olivocerebellar tract
|
|
|
Granule cell: Purkinje cell ratio
|
the evolution of the cerebellar cortex that correlates with the acquisition of dexterity and the manipulative abilities in humans
|
|
|
Excitation of Purkinje cells
|
- main output neurons of the cerebellar cortex (Purkinje cells) are excited by climbing fibers and Mossy fibers (via the parallel fibers of granule cells
|
|
|
Functional circuitry
|
- excited Purkinje cells inhibit spontaneously active deep cerebellar nuclei (excitatory collaterals from the climbing and Mossy fibers set the threshold for the inhibition of the deep cerebellar nuclei neurons)
|
|
|
Center-surround inhibition
|
- Excitation of the narrow beam of parallel fibers excites an array of Purkinje cells and basket cells
|
|
|
What does the cerebellum fine coordinate?
|
movement and balance;Where does the cerebellum receive its input
|
|
|
pons - relays information from the cerebral cortex about the (goals) of the intended movement;Function of cerebellum
|
compares sensory and goal information to calculate the sequence of muscle contractions (tactics)
|
|
|
- one of the first structures to differentiate but one of the last to mature
|
mostly after birth;Development of the cerebellum
|
|
|
- from lateral outgrowths (rhombic lips)
|
grow toward midline and fuse to form the vermis
|
|
|
- cells from metencephalon AND mesencephalon contribute to development of the cerebellum;Rhombic lips
|
- lateral growth of rhombomere 1
|
|
|
- grow toward midline and fuse to form the vermis;Cerebellar neurons origin
|
Two different germinal matrices:
|
|
|
1. Ventricular germinal matrix - progenitors near the ventricle (ventricular zone) in the cerebellar primordia migrate vertically/laterally to generate neurons of the deep cerebellar nuclei
|
Purkinje cells and interneurons
|
|
|
2. Specialized germinal matrix - progenitors in the rhombic lips
|
migrate radially over the surface of the cerebellar primordia to form the outer granular layer; progenitors then migrate deeper beyond the Purkinje cell layer in the cortex to differentiate into granule cells; migration continues during the 1st year of life;Ventricular germinal matrix
|
|
|
- migration continues during the 1st year of life;Molecular layer
|
- outler layering underlying the pia
|
|
|
-transversed by parallel fibers (unmyelinated fibers of granule cells);Cerebellum attachments to brainstem
|
1. inferior cerebellar peduncles (restiform body) - afferent sensory information about position of body in space from SC; also carries efferent info from vermis to brain stems
|
|
|
3. superior cerebellar peduncles (branchium conjunctivum) efferent feedback to midbrain and thalamus (and motor cortex);inferior cerebellar peduncles (restiform body)
|
- afferent sensory information about position of body in space (dorsal spinocerebellar
|
|
|
- also carries efferent info from vermis to brain stems;middle cerebellar peduncles (branchium pontis)
|
- afferent information from pontocerebellar fibers to neocerebellum (pontocerebellum) about intended goals from the cerebral cortex;superior cerebellar peduncles (branchium conjunctivum)
|
|
|
- afferent pathway - ventral spinocerebellar tract;Cerebellum organization
|
1. outer cerebellar cortex
|
|
|
3. deep cerebellar nuclei;Pairs of deep cerebellar nuclei
|
arranged on each side of the midline - that send projections out to each specific mediolateral subdivision of the cerebral cortex
|
|
|
* flocculonodular lobe does not have a deep cerebellar nuclei and projects directly to the brainstem (lateral and medial vestibular nuclei);Fastigial nuclei
|
- output from the vermis
|
|
|
- most medial;Interposed nuclei
|
- globose + emboliform
|
|
|
- lie lateral to fastigial nuclei;Dentate nucleus
|
- output from lateral lobe
|
|
|
- decussation of superior cerebellar peduncle is in the caudal midbrain tegmentum;Flocculonodular lobe
|
- does NOT have a deep cerebellar nuclei
|
|
|
- projects to vestibular nuclei (balance and eye movement);Rostrocaudal subdivision (phyllogenetic subdivision) of cerebellum
|
- divided by transverse fissures = folia
|
|
|
- posterolateral fissure = separates posterior lobe from flocculonodular lobe;primary fissure
|
separates anterior lobe from posterior lobe;posterolateral fissure
|
|
|
- 1. central 2. culmen;posterior lobe
|
- next most recent evolved (after anterior)
|
|
|
- 1. declive 2. folium 3. tuber 4. pyramis 5. uvula (tonsil);flocculonodular lobe
|
- oldest
|
|
|
- 1. flocculus laterally 2. nodulus medially;lobules
|
additional shallow fissures divide each lobe into smaller groups (9)
|
|
|
1. central 2. culmen (anterior) 3. declive 4. folium 5. tuber. 6. pyramis 7. uvula (or tonsil) (posterior) 8. flocculus 9. nodulus (flocculonodular);Mediolateral subdivision (functional subdivision)
|
- divided mediolaterally by two longitudinal fissures
|
|
|
- each cerebellar hemisphere is subdivided into an intermediate and lateral lobe;Spinocerebellum
|
- 1. vermis + 2. intermediate hemisphere
|
|
|
- output to motor execution via fastigial and interposed nuclei;Cerebrocerebellum (lateral hemisphere)
|
- lateral lobe
|
|
|
- has cognitive function also;Vestibulocerebellum
|
- flocculonodular lobe
|
|
|
- no deep cerebellar nuclei;Cellular organization in the cerebellar cortex
|
- 5 neuronal cell types arranged in 3 layers:
|
|
|
3. Granule cell layer - inner layer overlying white matter;Purkinje cell layer
|
- middle layer of cerebellar cortex
|
|
|
- Purkinje cells (main OUTPUT neurons of the cortex); inhibitory GABAergic
|
axons synapse with deep cerebellar and vestibular nuclei
|
|
|
- climbing fibers from inferior olivary nucleus in the medulla (wrap around Purkinje cells and form a powerful excitatory synapse in the proximal portion of dendrities) = a single AP in the climbing fiber elicits a large AP followed by a staccato of smaller APs;Granule cell layer
|
- deepest layer of the cerebellar cortex
|
|
|
- parallel fibers make synaptic contacts with Purkinje
|
stellate
|
|
|
- inhibited by Golgi cells and excited by mossy fibers;Parallel fibers
|
- unmyelinated axons of the granule cells
|
|
|
- extend into the molecular layer;Mossy fibers
|
- afferent excitatory fibers of the 1. spinocerebellar 2. pontocerebellar and 3. vestibulocerebellar tracts
|
|
|
- from spinal cord
|
external cuneate nucleus
|
|
|
- excite granule cells to discharge through their parallel fibers;Climbing fibers
|
- afferent excitatory (via aspartate) fibers of olivocerebellar tract
|
|
|
- terminate on neurons of the cerebellar nuclei and dendrites of Purkinje cells;Granule cell: Purkinje cell ratio
|
the evolution of the cerebellar cortex that correlates with the acquisition of dexterity and the manipulative abilities in humans;Excitation of Purkinje cells
|
|
|
- regulated also by inhibitory interneurons
|
basket and stellate cells (axons of these cells are on either side of the narrow beam of parallel fibers that originate in a small cluster of the granule cells
|
|
|
- Excitation of the basket cells leads to inhibition of Purkinje cells outside the narrow beam of parallel fibers = center-surround inhibition (makes inhibitory output of the cerebellar cortex spatial);Functional circuitry
|
- excited Purkinje cells inhibit spontaneously active deep cerebellar nuclei (excitatory collaterals from the climbing and Mossy fibers set the threshold for the inhibition of the deep cerebellar nuclei neurons)
|
|
|
- Excitation of Golgi type II cells by the parallel fibers causes the inhibition of granule cells (helps set the threshold of excitation of granule cells by the Mossy fibers);Center-surround inhibition
|
- Excitation of the narrow beam of parallel fibers excites an array of Purkinje cells and basket cells
|
|
|
What does the cerebellum fine coordinate?
|
movement and balance
|
|
|
Where does the cerebellum receive its input
|
spinal cord - position of the body with respect to space and time (sensory)
|
|
|
Function of cerebellum
|
compares sensory and goal information to calculate the sequence of muscle contractions (tactics), required to achieve the goal
|
|
|
Cerebellum facts
|
- constitues 10% of the brain volume but contains more than half of the entire neuronal population
|
|
|
Development of the cerebellum
|
- originates from the most rostral segment of the metencephalon (rhombomere 1)
|
|
|
Rhombic lips
|
- lateral growth of rhombomere 1
|
|
|
Cerebellar neurons origin
|
Two different germinal matrices:
|
|
|
2. Specialized germinal matrix - progenitors in the rhombic lips, migrate radially over the surface of the cerebellar primordia to form the outer granular layer
|
progenitors then migrate deeper beyond the Purkinje cell layer in the cortex to differentiate into granule cells
|
|
|
Ventricular germinal matrix
|
progenitors near the ventricle (ventricular zone) in the cerebellar primordia migrate vertically/laterally to generate neurons of the 1. deep cerebellar nuclei, 2. Purkinje cells and 3. interneurons
|
|
|
Specialized germinal matrix
|
- progenitors in the rhombic lips, migrate radially over the surface of the cerebellar primordia to form the outer granular layer
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Molecular layer
|
- outler layering underlying the pia
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Cerebellum attachments to brainstem
|
1. inferior cerebellar peduncles (restiform body) - afferent sensory information about position of body in space from SC
|
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|
inferior cerebellar peduncles (restiform body)
|
- afferent sensory information about position of body in space (dorsal spinocerebellar, cuneocerebellar and olivocerebellar tract - from contralateral inferior olivary nucleus)
|
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|
middle cerebellar peduncles (branchium pontis)
|
- afferent information from pontocerebellar fibers to neocerebellum (pontocerebellum) about intended goals from the cerebral cortex
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superior cerebellar peduncles (branchium conjunctivum)
|
- efferent feedback to midbrain and thalamus (dentatothalamic tract - terminates in ventral lateral nucleus of the thalamus)
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Cerebellum organization
|
1. outer cerebellar cortex
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|
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Pairs of deep cerebellar nuclei
|
arranged on each side of the midline - that send projections out to each specific mediolateral subdivision of the cerebral cortex
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Fastigial nuclei
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- output from the vermis
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Interposed nuclei
|
- globose + emboliform
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Dentate nucleus
|
- output from lateral lobe
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Flocculonodular lobe
|
- does NOT have a deep cerebellar nuclei
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Rostrocaudal subdivision (phyllogenetic subdivision) of cerebellum
|
- divided by transverse fissures = folia
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primary fissure
|
separates anterior lobe from posterior lobe
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posterolateral fissure
|
separates posterior lobe from flocculonodular lobe
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anterior lobe
|
- most evolved portion
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posterior lobe
|
- next most recent evolved (after anterior)
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flocculonodular lobe
|
- oldest, most primitive lobe
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lobules
|
additional shallow fissures divide each lobe into smaller groups (9)
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|
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Mediolateral subdivision (functional subdivision)
|
- divided mediolaterally by two longitudinal fissures
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Spinocerebellum
|
- 1. vermis + 2. intermediate hemisphere
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Cerebrocerebellum (lateral hemisphere)
|
- lateral lobe
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Vestibulocerebellum
|
- flocculonodular lobe
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Cellular organization in the cerebellar cortex
|
- 5 neuronal cell types arranged in 3 layers:
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|
|
Purkinje cell layer
|
- middle layer of cerebellar cortex
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|
- Purkinje cells (main OUTPUT neurons of the cortex)
|
inhibitory GABAergic, axons synapse with deep cerebellar and vestibular nuclei
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Granule cell layer
|
- deepest layer of the cerebellar cortex
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|
Granule cells
|
- excite (via glutamate) 1. Purkinje 2. basket 3. stellate 4. Golgi II cells through parallel fibers
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Parallel fibers
|
- unmyelinated axons of the granule cells
|
|
|
Mossy fibers
|
- afferent excitatory fibers of the 1. spinocerebellar 2. pontocerebellar and 3. vestibulocerebellar tracts
|
|
|
Climbing fibers
|
- afferent excitatory (via aspartate) fibers of olivocerebellar tract
|
|
|
Granule cell: Purkinje cell ratio
|
the evolution of the cerebellar cortex that correlates with the acquisition of dexterity and the manipulative abilities in humans
|
|
|
Excitation of Purkinje cells
|
- main output neurons of the cerebellar cortex (Purkinje cells) are excited by climbing fibers and Mossy fibers (via the parallel fibers of granule cells
|
|
|
Functional circuitry
|
- excited Purkinje cells inhibit spontaneously active deep cerebellar nuclei (excitatory collaterals from the climbing and Mossy fibers set the threshold for the inhibition of the deep cerebellar nuclei neurons)
|
|
|
Center-surround inhibition
|
- Excitation of the narrow beam of parallel fibers excites an array of Purkinje cells and basket cells
|
|
|
What does the cerebellum fine coordinate?
|
movement and balance
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Where does the cerebellum receive its input
|
spinal cord - position of the body with respect to space and time (sensory)
|
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Function of cerebellum
|
compares sensory and goal information to calculate the sequence of muscle contractions (tactics), required to achieve the goal
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Cerebellum facts
|
- constitues 10% of the brain volume but contains more than half of the entire neuronal population
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Development of the cerebellum
|
- originates from the most rostral segment of the metencephalon (rhombomere 1)
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Rhombic lips
|
- lateral growth of rhombomere 1
|
|
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Cerebellar neurons origin
|
Two different germinal matrices:
|
|
|
Ventricular germinal matrix
|
progenitors near the ventricle (ventricular zone) in the cerebellar primordia migrate vertically/laterally to generate neurons of the 1. deep cerebellar nuclei, 2. Purkinje cells and 3. interneurons
|
|
|
Specialized germinal matrix
|
- progenitors in the rhombic lips, migrate radially over the surface of the cerebellar primordia to form the outer granular layer
|
|
|
Molecular layer
|
- outler layering underlying the pia
|
|
|
Cerebellum attachments to brainstem
|
1. inferior cerebellar peduncles (restiform body) - afferent sensory information about position of body in space from SC; also carries efferent info from vermis to brain stems
|
|
|
inferior cerebellar peduncles (restiform body)
|
- afferent sensory information about position of body in space (dorsal spinocerebellar, cuneocerebellar and olivocerebellar tract - from contralateral inferior olivary nucleus)
|
|
|
middle cerebellar peduncles (branchium pontis)
|
- afferent information from pontocerebellar fibers to neocerebellum (pontocerebellum) about intended goals from the cerebral cortex
|
|
|
superior cerebellar peduncles (branchium conjunctivum)
|
- efferent feedback to midbrain and thalamus (dentatothalamic tract - terminates in ventral lateral nucleus of the thalamus)
|
|
|
Cerebellum organization
|
1. outer cerebellar cortex
|
|
|
Pairs of deep cerebellar nuclei
|
arranged on each side of the midline - that send projections out to each specific mediolateral subdivision of the cerebral cortex
|
|
|
Fastigial nuclei
|
- output from the vermis
|
|
|
Interposed nuclei
|
- globose + emboliform
|
|
|
Dentate nucleus
|
- output from lateral lobe
|
|
|
Flocculonodular lobe
|
- does NOT have a deep cerebellar nuclei
|
|
|
Rostrocaudal subdivision (phyllogenetic subdivision) of cerebellum
|
- divided by transverse fissures = folia
|
|
|
primary fissure
|
separates anterior lobe from posterior lobe
|
|
|
posterolateral fissure
|
separates posterior lobe from flocculonodular lobe
|
|
|
anterior lobe
|
- most evolved portion
|
|
|
posterior lobe
|
- next most recent evolved (after anterior)
|
|
|
flocculonodular lobe
|
- oldest, most primitive lobe
|
|
|
lobules
|
additional shallow fissures divide each lobe into smaller groups (9)
|
|
|
Mediolateral subdivision (functional subdivision)
|
- divided mediolaterally by two longitudinal fissures
|
|
|
Spinocerebellum
|
- 1. vermis + 2. intermediate hemisphere
|
|
|
Cerebrocerebellum (lateral hemisphere)
|
- lateral lobe
|
|
|
Vestibulocerebellum
|
- flocculonodular lobe
|
|
|
Cellular organization in the cerebellar cortex
|
- 5 neuronal cell types arranged in 3 layers:
|
|
|
Purkinje cell layer
|
- middle layer of cerebellar cortex
|
|
|
Granule cell layer
|
- deepest layer of the cerebellar cortex
|
|
|
Granule cells
|
- excite (via glutamate) 1. Purkinje 2. basket 3. stellate 4. Golgi II cells through parallel fibers
|
|
|
Parallel fibers
|
- unmyelinated axons of the granule cells
|
|
|
Mossy fibers
|
- afferent excitatory fibers of the 1. spinocerebellar 2. pontocerebellar and 3. vestibulocerebellar tracts
|
|
|
Climbing fibers
|
- afferent excitatory (via aspartate) fibers of olivocerebellar tract
|
|
|
Granule cell: Purkinje cell ratio
|
the evolution of the cerebellar cortex that correlates with the acquisition of dexterity and the manipulative abilities in humans
|
|
|
Excitation of Purkinje cells
|
- main output neurons of the cerebellar cortex (Purkinje cells) are excited by climbing fibers and Mossy fibers (via the parallel fibers of granule cells
|
|
|
Functional circuitry
|
- excited Purkinje cells inhibit spontaneously active deep cerebellar nuclei (excitatory collaterals from the climbing and Mossy fibers set the threshold for the inhibition of the deep cerebellar nuclei neurons)
|
|
|
Center-surround inhibition
|
- Excitation of the narrow beam of parallel fibers excites an array of Purkinje cells and basket cells
|
