Neuro 15

Front 1

how does the cerebellum exert influence

Back 1

through connections to motor systems of the cortex and brainstem; does NOT have direct connections with LMNs

Front 2

what do the inferior vermis and flocculonodular lobes regulate

Back 2

balance and eye movements through interactions with the vestibular circuitry

Front 3

more lateral cerebellar regions control

Back 3

lateral motor systems

Front 4

large regions of most of the lateral cerebellar hemispheres are important in

Back 4

motor planning

Front 5

what do cerebellar lesions generally cause

Back 5

ataxia - characterisitc type of irregular uncoordinated movement

Front 6

how can cerebellar lesions be localized

Back 6

1) ataxia is ipsilateral to side of cerebellar lesion 2) midline lesions of cerebellar vermis/flocculonodular lobes mainly cause unsteady gait (truncal) and eye movement abnormalities (along with vertigo, nausea, vomiting) 3) lesions lateral to cerebellar vermis mainly cause ataxia of limbs

Front 7

what other fxns do cerebellar pathways participate in

Back 7

speech articulation, respiratory movements, motor learning, and possibly certain higher-order cognitive processes

Front 8

what attaches the cerebellum to the brainstem

Back 8

cerebellar peduncles - 3 white matter tracts

Front 9

what connections does the flocculonodular lobe have

Back 9

vestibular nuclei connections

Front 10

most inferior portion of the cerebellar vermis

Back 10

nodulus

Front 11

folia

Back 11

small ridges running from medial to lateral on the surface of the ccrebellum (gyri)

Front 12

what does the superior cerebellar peduncle carry

Back 12

mainly outputs from the cerebellum

Front 13

what do the middle and inferior cerebellar peduncles carry

Back 13

inputs to the cerebellum

Front 14

where does the superior cerebellar peduncle descutate

Back 14

midbrain at level of the inferior colliculi (brachium conjunctivum)

Front 15

alternative name for middle cerebellar peduncle

Back 15

brachium pontis

Front 16

alternative name for the inferior cerebellar peduncle

Back 16

restiform body meaning 'rope-like body'

Front 17

what lobes are important in control of proximal and trunck muscles and in vestibulo-ocular control respectively

Back 17

vermis and flocculonodular lobes

Front 18

what part of the cerebellum is mainly involved in control of more distal appendicular muscles in the arms and legs

Back 18

intermediate part of cerebellar hemisphere

Front 19

what part of the cerebellum is involved in planning the motor program for extremities

Back 19

lateral part

Front 20

where are outputs relayed from in the cerebellum

Back 20

deep cerebellar nuclei and vestibular nuclei

Front 21

what are the deep cerebellar nuclei (roof nuclei)

Back 21

dentate, emboliform, globose, fastigial (Don't Eat Greasy Foods)

Front 22

where does the dentate nucleus receive projections from

Back 22

lateral cerebellar hemispheres

Front 23

interposed nuclei and inputs

Back 23

emboliform and globuse nuclei; receive input from intermediate part of cerebellar hemispheres

Front 24

where do fastigial nuclei recive input from

Back 24

vermis, and small input from flocculonodular lobe

Front 25

where do most fibers leaving the inferior vermis and flocculi project to

Back 25

vestibular nuclei

Front 26

three layers of cerebellar cortex

Back 26

granule cell layer, purkinje cell layer, and molecular layer

Front 27

what is in the molecular layer

Back 27

inmyelinated granule cell axons, purkinje cell dendrites, and several types of interneurons

Front 28

two primary kinds of synaptic inputs to the cerebellum

Back 28

1) mossy fibers 2) climbing fibers

Front 29

mossy fibers

Back 29

ascend through cerebellar white matter to form excitatory synapses onto dendrites of the granule cells

Front 30

where do granule cells send axons to

Back 30

into molecular layer, bifurcate forming parallel fibers that run parallel to the folia and form excitatory synaptic connections with numerous Pukinje cells

Front 31

what carries all output from the cerebellar cortex

Back 31

axons of purkinje cells into cerebellar white matter

Front 32

what kind of synapses do purkinje cells form

Back 32

inhibitory synapses onto deep cerebellar nuclei and vestibular nuclei, which then convey outputs from cerebellum to other regions through excitatory synapses

Front 33

climbing fibers

Back 33

arise exclusively from neurons in the contralateral inferior olivary nucleus; they wrap around the cell body and proximal dendritic tree of purkinje cells forming powerfully excitatory synapses

Front 34

inhibitory interneurons

Back 34

basket cells and stellate cells in the molecular layer

Front 35

what are basket and stellate cells excited by

Back 35

inputs from granule cell parallel fibers

Front 36

where do basket and stellate cells project to

Back 36

travel rostral to caudal perpendicular to parallel fibers to cause lateral inhibition of adjacent purkinje cells

Front 37

where do stellate cells terminate

Back 37

purkinje cell dendrites

Front 38

where do basket cells terminate

Back 38

form strong inhibitory basketlike connections on purkinje cells

Front 39

golgi cells

Back 39

in granule cell layer, recive excitatory inputs from granule cell parallel fibers in molecular layer and provide feedback inhibition onto granule cell dendrites

Front 40

cerebellar glomerulus

Back 40

small clearings amoung granule cells; contain axons and dendrites encapsulated in a glial sheath

Front 41

two types of inputs in glomeruli

Back 41

large mossy fiber axon terminals and golgi cell axon terminals, which form synapses onto one type of postsynaptic cell (granules cell dendrites)

Front 42

simple way to remember excitatory and inhibitory processes of cerebellar cortex

Back 42

axons projecting upward are excitatory (mossy, climbing, granule cell parallel fibers) and axons projecting downward are inhibitory (purkinje, stellate, basket, and goli cells)

Front 43

where does the dentate nucleus project to and where does it decussate

Back 43

superior cerebellar peduncle, decussates in the midbrain to reach the contralateral ventral lateral nucleus (VL) of the thalamus

Front 44

large rostral parvocellular division of the red nucleus

Back 44

involved in cerebellar circuitry and projects to the inferior olive; dentate nucleus projects here

Front 45

magnocellular division of the red nucleus

Back 45

gives rise to the rubrospinal tract

Front 46

where do the interposed nuclei project to

Back 46

superior cerebellar peduncle to contralateral VL - influences lateral corticospinal tract; also project to contralateral magnocellular division of red nucleus

Front 47

how do the cerebellar vermis an flocculonodular lobes affect proximal trunk movements and vestibulo-ocular control

Back 47

connections to medial motor pathways (anterior corticospinal, reticulospinal, vestibulospinal, and tectospinal for trunk and medial longitundinal fasciculus for eyes)

Front 48

what projects to the fastigial nucleus

Back 48

inferior vermis and flocculonodular have small projections here (mostly to vestibular nuclei)

Front 49

where do outputs from fastigial nucleus go

Back 49

pathways running along with superior cerebellar peduncle and inferior cerebellar peduncles (called uncinate fasciculus and juxtarestiform body)

Front 50

juxtarestiform body

Back 50

lying on lateral wall of 4th ventricle; carries fibers both ways btwn vestibular nuclei and cerebellum

Front 51

what are reciprical connections btwn cerebellum and and vestibular nuclei important for

Back 51

equilibrium and balance

Front 52

where do inputs to the cerebellum come from

Back 52

1) virtually all areas of cerebral cortex 2) multiple sensory modalities (vestibular, visual, auditory, somatosensory) 3) brainstem nuclei 4) spinal cord

Front 53

what are celebellar inputs carried by

Back 53

mossy fibers, except those from the inferior olivary nucleus which is via climbing fibers

Front 54

major source of input to cerebellum and where do they come from

Back 54

corticopontine fibers; primary sensory and motor cortices and visual cortex make the largest comtributions

Front 55

where do corticopontine fibers synapse

Back 55

in pontine nuclei, then cross midline to enter contralateral middle cerebral peduncle and give rise to mossy fibers

Front 56

4 tracts from spinal cords that go to cerebellum

Back 56

dorsal and ventral spinocerebellar tracts for lower extremities and cuneocerebellar and rostral spinocerebellar tracts for upper extremities and neck

Front 57

2 kinds of feedback info from spinocerebellar tracts

Back 57

1) afferent info about limb movements by dorsal and cuneocerebellar tracts 2) info about spinal cord interneurons by ventral and rostral spinocerebellar tracts

Front 58

where does the dorsal spinocerebellar tract ascend

Back 58

near surface of spinal cord just lateral to lateral corticospinal tract

Front 59

where do fibers of the dorsal spinocerebellar tract come from

Back 59

large, myelinated axons of primary sensory neurons carrying proprioception, touch, and P sense enter dorsal roots and ascend in gracile fasciculus, rather than continuing some synapse in nucleus dorsalis of clark to ascend ipsilaterally in dorsal spinocerebellar tract

Front 60

what do the fibers in the dorsal spinocerebellar tract give rise to

Back 60

mossy fibers that travel in ipsilateral cerebellar cortex via inferior cerebellar peduncle

Front 61

upper-extremity equivalent of the dorsal spinocerebellar tract

Back 61

cuneocerebellar tract

Front 62

what do the dorsal and cuneocerebellar tracts allow the cerebellum to control

Back 62

provide rapid feedback to allow fine adjustments of movement to be made

Front 63

where does the ventral spinocerebellar tract arise

Back 63

neurons along the outer edge of the central gray matter called spinal border cells and from scattered neurons in the spinal cord intermediate zone

Front 64

where do fibers of the ventral spinocerebellar tract ascend

Back 64

cross over in ventral commisure of spinal cord to ascend in ventral spinocerebellar tract ventral to the dorsal spinocerebellar tract and peripheral to the anterolateral systems

Front 65

how do the ventral spinocerebellar tract fibers get to the cerebellum

Back 65

majority join superior cerebellar peduncle and cross a second time to reach ipsilateral side of where pathway began

Front 66

where does the rostral spinocerebellar tract enter the cerebellum

Back 66

via inferior and superior cerebellar peduncles

Front 67

how do fibers from the inferior olivary nuclear complex enter cerebellum

Back 67

cross the medulla to enter contralateral cerebellum; form major portion of inferior cerebellar peduncle and terminate as climbing fibers

Front 68

the lateral reticular nucleus project via the inferior cerebellar peduncle and gives rise to

Back 68

mossy fibers

Front 69

what provides a neuromodulatory role in the cerebellum

Back 69

noradrenergic inputs from locus ceruleus and serotonergic inputs from the raphe nuclei; not via climbing or mossy fibers!

Front 70

blood supply to cerebellum

Back 70

PICA, AICA, and SCA

Front 71

where does PICA generally arise

Back 71

from verebral artery

Front 72

where does AICA generally arise

Back 72

from lower basilar just below the PCA

Front 73

what does PICA supply

Back 73

lateral medulla, most of the inferior half of the cerebellum, and inferior vermis

Front 74

What does AICA supply

Back 74

inferior lateral pons, middle cerebellar peduncle, strip of ventral cerebellum btwn PICA and SCA including flocculus

Front 75

What does SCA supply

Back 75

upper lateral pons, superior cerebellar peduncle, most superior half of cerebellar hemisphere including deep cerebellar nuclei and superior vermis

Front 76

what do patients with cerebellar infarcts present with

Back 76

vertigo, nausea and vomiting, horizontal nystagmus, limb ataxia, unsteady gait, headache; along with affected regions of pons or medulla

Front 77

what can cause ataxia without cerebellum involvment

Back 77

cerebellar peduncles via infarction of lateral medulla or pons

Front 78

what infarcts tend to affect only the cerebellum and spare the brainstem

Back 78

SCA infarcts

Front 79

what infarcts can lead to swellin gof cerebellum and compression of the 4th ventricle

Back 79

PICA and SCA

Front 80

fatal gastroenteritis

Back 80

cerebral hemorrhage with only symptoms of nausea and vomiting

Front 81

lesions around the cerebellar vermis affect

Back 81

medial motor systems - wide base and unsteady, drunk-like gait

Front 82

what can hydrocephalus involve that resembles cerebellar ataxia

Back 82

damage to frontopontine pathways; lesions of the prefrontal cortex can cause same affect

Front 83

ataxia-hemiparesis

Back 83

syndrome often caused by lacunar infarcts; combination of unilateral UMN signs and ataxia usually affecting the same side (contralateral to lesion)

Front 84

what lesions can cause ataxia-hemiparesis

Back 84

corona radiata, internal capsule or pons that involve both corticospinal and corticopontine fibers; also frontal, parietal, or sensorimotor cortex, or midbrain lesions involving fibers of superior cerebellar peduncle or red nucleus

Front 85

sensory ataxia

Back 85

posterior-column-medial lemniscal pathway disrupted resulting in loss of position sense; worse when eyes closed

Front 86

when is head tilt seen in cerebellar lesions

Back 86

extending to the anterior medullary velum which may affect trochlear nerves

Front 87

dysmetria

Back 87

abnormal under or overshoot during movements toward a target

Front 88

dysrhythmia

Back 88

abnormal rhythm and timing of movements

Front 89

myoclonus

Back 89

sudden, rapid-movement disorder

Front 90

postural tremor

Back 90

apply P to patient outstretch arm and release is abnormal; large0amplitude in cerebellar lesions

Front 91

titubation

Back 91

pecular tremor of the trunk or head; can occur with midline cerebellar lesions

Front 92

gaze paretic type of nystagmus

Back 92

slow phases toward primary position and fast phases occur back to target; can change directions in cerebellar lesions

Front 93

scanning or explosive speech

Back 93

irregular fluctuations in both rate and volume