test 1: lecture 12 Flashcards
The ___ cannot initiate movement but rather coordinates it.
cerebellum
the cerebellum is separated from the cerebral hemispheres by ___
the tentorium cerebelli
two main fissures of the cerebellum
primary fissure
posterolateral/caudolateral/uvulonodular
three lobes of the cerebellum
- The anterior/rostral lobe
- The posterior/caudal lobe
- The flocculonodular lobe
vermis
The cerebellum consists of a midline vermis and two ___
hemispheres
instead of sulci and gyri, cerebellum has
sulci
folia (little folds)
•Projections of the white matter extend within the folia in a tree-like fashion termed the___
arbor vitae.
three deep cerebellar nuclei
sit in the white matter of the cerebellum
–Dentate (lateral)–Interpositus–Fastigial
how the cerebellum attatched to the rest of the brain
attached to brainstem by three paired cerebellar peduncles
inferior(caudal), middle and superior(rostral)
•Rostral cerebellar peduncle connects to the ___
midbrain
•Middle cerebellar peduncle connects to the ___
pons
•Caudal peduncle connects to the ___
medulla oblongata
10, 11, 12?
•Rostral peduncle (#12) connects to the midbrain
•Middle peduncle (#10) connects to the pons
•Caudal peduncle (#11) connects to the medulla oblongata
layers of the cerebellum
–Molecular layer
–Purkinje cell layer
–Granular cell layer
(MPG)
molecular layer of the cerebellum
outermost layer
no neurons, glial cells, neuronal processes
purkinje cell layer of the cerebellum
2nd layer
neurons of purkinje cells live here
project dentrites into the molecular layer
send axon through granular layer→ white matter → synapse on cerebellar nucleus inside the white matter
granular cell layer of the cerebellum
3rd layer
1000s of neurons
where do purkinje fibers synapse?
neurons of purkinje cells live here
project dentrites into the molecular layer
send axon through granular layer→ white matter → synapse on cerebellar nucleus inside the white matter
white arrows?
purkinje cells of the cerebellum
(below is the granular cell layer)
(above is the molecular layer)
1.All afferent fibers to the cerebellar cortex (mossy and climbing) are ___
excitatory.
___ are excited by climbing and mossy fibers; they are inhibited by interneurons from the cortex.
1.Purkinje cells
Outgoing fibers from the cerebellar cortex are axons from Purkinje cells. They are ___
inhibitory
Neurons of the ___ nuclei and the ___ nuclei receive inhibitory projections from Purkinje cells.
cerebellar
vestibular
1.Neurons of the cerebellar nuclei are ___
excitatory
Cerebellar nuclei projections can be___
excitatory or silent but not inhibitory.
All ___ fibers to the cerebellar cortex (mossy and climbing) are excitatory
afferent
how do mossy fibers work?
mossy from brainstem and spinal cord → granule neurons → purkinje cells
excitatory
Mossy fibers, from the brainstem and spinal cord, have collaterals which synapse on cerebellar nuclei with the main axon terminating on granule neurons.
Axons of granule neurons synapse on Purkinje cells.
___ from the brainstem and spinal cord, have collaterals which synapse on cerebellar nuclei with the main axon terminating on granule neurons.
Mossy fibers,
how do climbing fibers work?
directly synapse on purkinje cells
Climbing fibers, from the olivary nucleus, enter through the caudal cerebellar peduncle. They have collaterals which synapse on cerebellar nuclei with the main axon terminating on Purkinje neurons.
Climbing fibers, from the ____ , enter through the ___ cerebellar peduncle. They have collaterals which synapse on cerebellar nuclei with the main axon terminating on Purkinje neurons.
olivary nucleus
caudal
climbing fibers come from where and go where?
olivary nucleus
synapse on Purkinje neurons in the cerebellum
what cells are inhibitory to purkinje cells?
stellate neurons (interneurons)
(outer 1 , basket 2, golgi cells 3)
___ are cerebellar afferent pathways with general proprioception
information
Spinocerebellar(unconscious proprioception)
cuneocerebellar tracts (upper limb unconscious proprioception)
lower limb = dorsal spinocerebellar → sensory into spinal cord → synapse in dorsal horn (clarks nucleus) → up to the cerebellar cortex by mossy fibers
upper limb= cuneocerebellar tract → sensory into spinal cord → synapse in accessory cuneate nucleus in the brain stem→ up to cerebellar cortex by mossy fibers
both are ipsilateral (same side)
Vestibulocerebellar tracts with vestibular information are delivered by ___
mossy fibers
type of afferent cerebellar pathway
___ tracts with visual and auditory information are carried by mossy fibers to the cerebellum
Tectocerebellar
afferent pathway
what are some cerebellar afferent pathways from upper motor neuron fibers?
Rubrocerebellar
Reticulocerebellar
Olivocerebellar→ Climbing fibers
Cerebropontocerebellar (pyramidal) →Mossy fibers
information from the olivocerebellar travel to the cerebellum by ___
climbing fibers
All outgoing fibers from the ___cortex are axons from Purkinje cells that are inhibitory.
cerebellar
Purkinje cells project to the ___ nuclei. Efferent axons from the cerebellar nuclei project to the brainstem and are ___. Some axons from Purkinje cells of the flocculonodular lobe project directly to the ___ nuclei.
cerebellar
excitatory.
vestibular
purkinje→ cerebellar nuclei are always inhibitory
cerebellar nuclei → brainstem are excitatory
In general, cerebellar efferent fibers do not project to the spinal cord but rather control motor activity by influencing ___pathways.
upper motor neuron
cerebellar cortex (purkinje cells) inhibitory → cerebellar nucleus
cerebellar nucleus excitatory → brain stem (thalamus, midbrain, medulla/pons)
how does cerebellum control movement
brain tells body to move → muscle fibers
at same time those same upper motor neurons will tell cerebellum we are moving through the olivary nucleus and pontine nucleus
the cerebellum will get information about proprioception from dorsal spinocerebellar and cuneocerebellar tracts
cerebellum takes this information and transfers back to brainstem and brain by cerebellar nucleus → red nucleus → thalamus → motor cortex (telencephalon)
lets make this smooth and controlled motion
two primary functions of the cerebellum
- Coordinate and regulate movement
- Control of posture
The ___ (archicerebellum) is confined to the ventral aspect of the cerebellum.
vestibulocerebellum
The ____(paleocerebellum) constitutes the midline.
spinocerebellum
The ____(pontocerebellum; neocerebellum) is predominantly the hemispheres.
cerebrocerebellum
princible sign of cerebellum dysfunction
ataxia
what part of the cerebellum is associated with balance
vestibulocerebellum
flocculonodular lobe
problems with the vestibulocerebellum:
disturbance of equilibrium (loss of balance)
issues with the spinocerebellum results in ___
– hypertonus and exaggeration of postural reflexes
(swaying side to side)
issues with the cerebrocerebellum results in __
asynergia; dysmetria, tremor, hypotonia
disease will be same side as tremor
how to test for issues with the vestibulocerebellum and spinocerebellum
tandem gait; observing for nystagmus and truncal ataxia.
how to test for cerebocerbellum issues
finger to nose, rebound, speech (dysarthria- uneven voice)
with cerebellum issues
ataxia. dsymetria (overstepping, understepping)
same side deficits
menace= wont blink when stimulated
intention tremors
