Cerebellum

lecture complete 4/2

the cerebellum sits within which fossa?

the posterior fossa

the cerebellum sits on the ___, meaning the cerebral tonsils can ___

foramen magnum, press on spinal column

the 4th ventricle is ___ to the cerebellum

ventral

what view of the cerebellum?

posterior

what view of the cerebellum?

anterior

what view of the cerebellum?

inferior

what view of the cerebellum?

superior

list the lobes and functional areas of the cerebellum.

lobes - anterior, posterior, flocculonodular

functional areas - spinocerebellum, cerebrocerebellum, and vestibulocerebellum

the vermis and paravermis are included in which functional area?

the spinocerebellum

what is highlighted in green?

superior cerebellar peduncle

what is highlighted in red?

middle cerebellar peduncle

what is highlighted in blue?

inferior cerebellar peduncle

what is the basic flow of info through the cerebellum?

inputs arrive at cerebellar cortex, which projects to deep nuclei, which provide output

input → cerebellar cortex → deep cerebellar nuclei → output

what are the transverse divisions of the cerebellum? what are the longitudinal divisions?

transverse: anterior lobe, posterior lobe, flocculonodular lobe

longitudinal: vermis, paramedian (paravermis), lateral

which longitudinal cerebellar region is specialized for body posture?

vermis

which longitudinal cerebellar region regulates gross movements of ipsilateral extremities (such as walking)?

paravermis

which longitudinal cerebellar region regulates skilled movements of the ipsilateral extremity?

lateral

what separates the anterior and posterior lobes of the cerebellum?

the primary fissure

which lobe of the cerebellum regulates eye movement and body posture?

flocculonodular lobe

which lobe of the cerebellum regulates movements of the legs?

the anterior lobe.

which lobe of the cerebellum regulates movements of the arms?

posterior lobe

1

middle peduncle

2

superior peduncle

3

flocculus

4

tonsil

5

vermis

list the 3 deep cerebellar nuclei

dentate nucleus, fastigial nucleus, and the interposed nucleus (emboliform and globose)

do the deep cerebellar nuclei receive inhibitory or excitatory signals from other parts of the brain?

they receive both inhibitory and excitatory signals 👍

which is the fastigial nucleus?

C (yellow)

which is the interposed nucleus?

B (purple)

which is the dentate nucleus?

A (green)

largest deep cerebellar nucleus, communicates through cerebellar peduncles

dentate nucleus

what is the function of the dentate nucleus?

coordinating fine limb movements

what is the function of the intermediate/interposed nucleus?

regulates ipsilateral extremity (gross movement)

what is the function of the fastigial nucleus?

regulates body posture via flocculonodular lobe

in terms of information entering/exiting the cerebellum, what does the middle cerebellar peduncle do?

input from pons

in terms of information entering/exiting the cerebellum, what does the inferior cerebellar peduncle do?

input from inferior olive, spinal cord, and vestibular nucleus

how does info from the frontal-motor/parietal cortex get to the cerebellum?

it goes through the VA thalamus, through the pons, through the middle cerebellar peduncle, to the cerebellum

what is the main input to the cerebellum?

the middle cerebellar peduncle

in terms of information entering/exiting the cerebellum, what does the superior cerebellar peduncle do?

output from cerebellum

how does info get from the cerebellum to the primary motor and premotor cortex?

it leaves the cerebellar cortex through deep cerebellar nuclei exiting through the superior cerebellar peduncle, through the VL thalamus → to cortex

what is the output target of the cerebrocerebellum? list deep cerebellar nuclei, other targets, and function

dentate nucleus → premotor cortex (UMNs) → motor planning

what is the output target of the spinocerebellum? list deep cerebellar nuclei, other targets, and function

interposed and fastigial nuclei → motor cortex and brainstem (UMNs) → motor execution

what is the output target of the vestibulocerebellum (FN lobe)? list deep cerebellar nuclei, other targets, and function

vestibular nuclei → LMNs in spinal cord and brainstem → balance and vestibulo-ocular regulation

1

superior cerebellar peduncle

2

inferior cerebellar peduncle

3

middle cerebellar peduncle

4

pons

5

midbrain

6

thalamus

cellularly, what are the output of the cerebellar cortex?

purkinje cells

list the three cerebellar cortex layers from innermost to outermost

granule, purkinje, molecular

cellularly, what are the inputs to the cerebellar cortex?

climbing fibers and mossy fibers

where do climbing fibers originate?

inferior olive (medulla)

climbing fibers (excite/inhibit) purkinje cells

excite

mossy fibers (excite/inhibit) granule cells

excite

granule cells (excite/inhibit) purkinje cells

excite

basket interneurons (excite/inhibit) purkinje cells

inhibit

purkinje cells (excite/inhibit) cerebellar nuclei

tonically inhibit

what are the primary functions of the cerebellum?

control posture, correct rapid movements initiated by cerebral cortex, motor learning, movement control

how does the cerebellum control movement?

cerebellum receives intention from motor cortex to start a voluntary movement. proprioceptors and visual signals inform cerebellum of body position. cerebellum plans best way to perform a movement and sends a “blueprint” to the motor cortex. errors sent to cerebellum for correction

nystagmus

jerky eye movements

ataxia

lack of coordination

dysarthria

speech difficulties

intention tremor

tremor upon movement

titubation

body wavering

dysdiadochokinesia

clumsy alternating movements

dysmetria

under/overshooting

where does the flocculonodular lobe receive input from?

vestibular input from semicircular canals and vestibular nuclei, visual input from superior colliculi and visual cortex

lesions of the ___ disturb eye tracking, balance, and gait

flocculonodular lobe

where does the paravermal region receive input from?

proprioceptive input from spinal cord, trigeminal nerve (CN V), visual and auditory systems

the paravermal region sends fibers to deep cerebellar nuclei, which project to cerebral cortex to ___

modulate descending motor systems

which region contains sensory maps, which track the position of body parts in space?

paravermal region

which region uses proprioceptive input to predict future position of a body part during movement?

paravermal

the lateral cerebellum receives input from ___ via ___

cerebral cortex via pontine nuclei

the lateral cerebellum sends fibers to

the thalamus and the red nucleus

which region is involved in planning movement about to occur and in cognitive functions?

lateral cerebellum

intention tremor, dysmetria, dysdiadochokinesia, and scanning speech (slow separation of syllables) are all signs of syndrome in the

posterior lobe

ataxia involving lower limbs suggests syndrome of the

anterior lobe

alcoholic degeneration of purkinje cells is associated with which lobe?

anterior lobe syndrome

truncal ataxia (titubation) is a sign of syndrome in which lobe?

flocculonodular

peduncles review: mainly efferents to red nucleus and thalamus

superior cerebellar peduncle

peduncles review: afferents from pons and cortex

middle cerebellar peduncles

peduncles review: mainly afferents and efferents from vestibular nuclei

inferior cerebellar peduncles

afferent vs efferent (in 3rd semester of neuro is crazy 💀)

afferent - towards CNS

efferent - exiting CNS

list the afferent pathways associated with the inferior cerebellar peduncle

olivocerebellar tract, vestibulocerebellar tract, dorsal spinocerebellar tract, cuneocerebellar tract

give the location and function: olivocerebellar tract

from spinal cord through olivary nucleus to contralateral cerebellum

function: source of climbing fibers for direct input to cerebellum

give the location and function: vestibulocerebellar tract

from semicircular canals through inferior peduncle

function: maintains upright posture

give the location and function: dorsal spinocerebellar tract

from reticular nuclei (which regulates sleep, respiration, heart rate)

function: unconscious proprioception from muscle spindles, golgi tendon organs, and skin

what information does the cuneocerebellar tract carry?

proprioception from the upper limbs and neck

the middle cerebellar peduncle carries info from ___ to ___

from pontine nuclei (from opposite cerebral cortex, visual and auditory inputs), to opposite cerebellar hemisphere

the superior cerebellar peduncle sends outputs to the

contralateral red nucleus (midbrain) and ventral lateral nucleus (thalamus)

ventral spinocerebellar tract

unconscious proprioception from muscle spindles, golgi tendon organs, and skin

is the ventral spinocerebellar tract ipsilateral or contralateral?

ipsilateral, it decussates first through the anterior white commissure (spinal cord) and second through the superior cerebellar peduncle

the vermis gets input from.. (what kind of input?)

spinal cord, somatosensory and kinesthetic information

damage to the vermis leads to

difficulty with postural adjustments

the intermediate zone (paravermis) receives input from

red nucleus and somatosensory information from spinal cord

damage to the paravermis results in

rigidity and difficulty in moving limbs

lateral zone receives input from

motor and association cortices through the pons

damage to the lateral zone leads to

overshooting of movements, lack of coordination of multi-joint movement, and poor muscle learning/movement timing