Lectures 39, 40: Cerebellum Flashcards Preview

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Flashcards in Lectures 39, 40: Cerebellum Deck (62):
1

Layers of the cerebellum (broadly)

Cortex, white matter, deep cerebellar nuclei

2

Structural hierarchy of cerebellum (small --> large)

Folium --> lobule --> lobe

3

Lobes of cerebellum and associated fissures

Anterior (primary fissure) posterior (pastero-lateral fissure) floccular-nodular

4

One important cerebellum lobule and location. What can happen to this lobule?

Tonsil: posterior, hangs down the furthest; tonsilar herniation

5

Locations of 3 cerebellar nuclei

Fastigial - vermis, Interposed - intermediate, Dentate - lateral

6

What are the vestibular portions of the cerebellum?

Floccular-nodular (nodular in vermis)

7

Cerebellum receives all of its input from...(broadly, 2)

Spinal cord and brainstem

8

How many spinocerebellar tracts are there and what do they carry?

4, proprioception and error information

9

2 lower body tracts and what they carry

Dorsal (proprioception) and ventral (error signal) spinocerebellar tract

10

2 upper body tracts and what they carry

Cuneocerebellar (proprioception) and rostral spinocerebellar (error signal)

11

How does error signals work?

These tracts also carry information from higher brain regions and through interneurons compute difference between intended and actual muscular states

12

Dorsal spinocerebellar tract ascends in which fascicle and terminates where? Then where does it ascend? Final synapse?

Gracile fascicle --> Clarke's nucleus in thoracic spinal cord --> dorsal spinocerebellar tract (DSCT) --> inferior cerebellar peduncle

13

Cuneocerebellar tract pathway

Cuneate fascile --> lateral cuneate nucleus (medulla) --> cuneocerebellar tract --> inferior cerebellar peduncle

14

Ventral spinocerebellar tract pathway

Afferents from Golgi Tendon Organ + corticospinal information --> Interneurons (spinal border cells) --> cross in anterior commissure --> lateral funiculus --> superior cerebellar peduncle where they CROSS AGAIN

15

Why is the ventral spinocerebellar tract anomalous

1. All other tracts travel via inferior cerebellar peduncle and 2. Double-crossed

16

Do we have to find upper body error tract? Also, what's this tract called again?

No! Hard to determine anatomically; rostral spinocerebellar tract

17

Cerebellar homunculi principles (2) and name for this region

At least two homunculi; trunk of the body in vermis and arms/legs on intermediate regions; spinocerebellum

18

Other cerebellar inputs from medulla...(3); inferior cerebellar peducle carries which two?

Reticular formation, inferior olivary complex, vestibular nuclei; reticular and inferior olivary complex

19

Does the cerebellum get input from the pons? Crossed or uncrossed?

Yes! Enormous projections from pontine nuclei; crossed...duh! crossing fibers of the pons, after all!

20

What do pontine projections to the cerebellum form?

Middle cerebellar peduncle

21

How does the cerebral cortex influence the cerebellum?

Synapse on pontine nuclei

22

How is the crux cerebri organized?

Topographically by brain lobe that's projecting

23

What portion of the cerebellum recieves pontine projections?

Lateral hemispheres (cerebrocerebellum)

24

Describe basic cerebellar connectivity (4 steps). Which cell type projects to deep cerebellar nuclei?

Cerebellar afferents --> cerebellar cortex --> deep cerebellar nuclei --> target nuclei; Purkinje cells

25

3 layers of the cerebellum and associated cell types

Molecular layer (stellate, basket cells and Purkinje dendrites), Purkinje layer, Granular layer (granule cells, Golgi cells)

26

Two fiber systems of cerebellum and associated input structure

Mossy fiber-Parallel fiber (all the rest of the inputs, distributed inputs) and Climbing fiber (axons from inferior olivary complex, convergent inputs)

27

Basket and stellate cells are...synapse on, which are?

Inhibitory; Purkinje cells, inhibitory

28

All cerebellar inputs are...All interneurons are...

Excitatory; inhibitory

29

Deep cerebellar nuclei project to what three structures. Terminate where, except? Which are crossed?

Thalamus, red nucleus, vestibular nuclei; superior cerebellar peduncle (except vestibular, which goes through inferior); tracts to thalamus/red nucleus are crossed

30

What portions of the thalamus receive cerebellar input? What tract (a tract by any other name...)?

Ventral group (VLp); dentato-thalamic tract (thalamic fasciculus w/ BG projections)

31

So, where do the outputs of the cerebellum mostly travel through?

Superior cerebellar peduncle

32

If a cerebellar deficit is unilateral, the deficit will be? Why?

Ipsilateral; cerebellar efferents are contralateral, synapse in cortex and then projects down contralaterally in motor pathways (ending in same side)

33

Ataxia definition

Unsteady gait, imbalance, broad-based stance

34

Guillan-Mollaret (Myoclonic) Triangle pathway and symptoms

Inferior olive --> dentate nucleus --> red nucleus; palatal myoclonus that PERSISTS during sleep

35

Eye movements that depend on cerebellum (2)

Smooth pursuit (cortico-ponto-cerebellar network), optokinetic nystagmus

36

Vermal cerebellar problems broadly involve (3)

Standing roblems (wide-based gait, ataxia of gait); nystagmus, ocular dysmetria

37

Define titubations

Spasmodic nodding of head and neck

38

Hemispheric cerebellar problems broadly involve...What about pancerebellar?

Coordination of ipsilateral limb movements, rapid alternating movements; pancerebellar is combination of both hemi and vermis syndromes

39

Classical cerebellar tremor is (broadly)

Intentional

40

Anatomical cerebellar syndrome classes

Vermis, hemispheric, pancerebellar

41

A common eye movement problem in dysfunction of cerebellum

Nystagmus

42

Testing of Station (three things to look for)

1. Position of feet (ataxia is less w/ broad based); 2. Eyes open/closed (cerebellar NOT improved by visual orientation); 3. Direction of falling (lateral lesion --> falling to ipsilateral side, midline lesion --> indiscriminate falling)

43

What can cerebellar problem do to tone? Some features.

Hypotonia; ipsilateral, often with acute lesions, more noticeable in upper limbs/proximal muscles

44

What are the cerebellar hemispheric function tests (3)?

Finger-to-nose, rapidly alternating movement, heel-to-sin test

45

Rapid alternating movements: real name and what it means

Dysdiadochokinesis; tests ability to change direction

46

Finger to nose tests what?

Dysmetria (lack of coordination)

47

Check and rebound show what if it's pathological?

Large rebound (overshoot)

48

Cerebellar dysarthria is an abnormality in what parts of speech?

Articulation and prosody: long pauses between words, may be related to hypotonia of muscles

49

Three types of tremor and definitions

Resting (max at rest, symptom of PD), postural (max with limb in fixed position against gravity), intention

50

Which tremor is more related to cerebellar disorder?

Intention

51

Physiologic tremor is normal/abnormal and enhanced by what?

Normal, anxiety/stress/fatigue

52

Essential tremor is...(genesis) and increases with what? What about at rest?

Hereditary (genetic); aging; absent at rest

53

Palatal myoclonus definition and lesion location. What's special about this?

Rhythmic jerks of soft palate, lesions of Guillan-Mollaret (Myoclonic) Triangle pathway; NOT suppressed by sleep

54

Hypothyroidism can cause...What else (nutritional)?

Cerebellar ataxia; heavy metals (MO) and Vit E deficiency

55

Antiepileptic drugs and the cerebellum

Long-term antiepileptic drugs may cause cerebellar atrophy

56

Infections and children with cerebellar ataxia

Children can present with acute cerebellar ataxia after a non-specific viral infection

57

What 2 viruses can be associated with cerebellar ataxia?

HIV and Creutzfeldt-Jakob disease

58

What is the relationship between cerebellar ataxia and cancer?

Paraneoplastic cerebellar degeneration syndrome (autoimmune process triggered by cancer)

59

What food item is related to cerebellar ataxia?

Gluten (Celiac's disease)

60

Define Friedreich ataxia

Progressive, genetic cerebellar ataxia w/ cardiomyopathy and diabetes

61

Define Ataxa-telangiectasia

Progressive ataxia with onset in infancy, genetic, capillary dilations (red nose) and malingnancies

62

Cardinal features of cerebellar dysfunction (7)

Hypotonia, ataxia, dysarthria, tremor, ocular motor dysfunction, decompensation of movement, impared rapid alternating movements

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