Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Chika- SF2 > Cerebellum- Wilson > Flashcards

Cerebellum- Wilson Flashcards

1
Q

What are interesting facts about cerebellum?

A
  • means little brain
  • constitutes only 10% of the brain’s volume
  • contains over 50% of all neurons
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Is the cerebellum a sensory or motor structure? What is the embryology of the cerebellum?

A

a motor structure

-you don’t have any cerebellum (insult)

lesion of cerebellum could result in loss of balance and not movement

the cerebellum comes from the alar plate (so embryonically speaking it is coming from sensory primordium)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does the cerebellum receive?

A

all sensory input from essentially all sensory receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the major output of the cerebellum?

A

is the ventral lateral nucleus of the thalamus which projects to areas 4 and 6 of the cortex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why do people not think of cerebellum as sensory?

A

if there is lesion you don’t get loss of sensory innervation but you do get lack of coordination in body movements

-no sensory information, transmitted to the cerebellum reaches consciousness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How do you control a motor system?

A

1) Feed-Forward Control

2) Feedback Control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Visual reflex is how fast?

A

at least 200 m/s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe the Feed-Forward Control

A

for a behavior or activity, you set an initial motor activity and don’t change it; if you don’t make the right motor program then this system misses its mark (point of no return)

  1. . starting position
  2. (anticipated) target position
  3. properly timed sequence of muscle contractions of appropriate velocities/strengths
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Feedback Control

A

-constantly developing feed forward control
and monitoring how the program is and adjusting it according to how far you are off the mark (you have unexpected changes,v the world is constantly changing)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What happens if there are unanticipated perturbations in the feed forward motor response because of program error and/or changes in the environment and/or target position?

A

you will not reach your goal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Pre central gyrus have close connections with the primary motor cortex. Explain.

A

Neural activity during flexion of the arm to a target

most of the signals come from the cerebellum (the primary generator to an adjustment due to unexpected changes)

somatosensory gyrus has close links with the primary motor cortex

Cerebellum is involved in generating the metric/numbers that are necessary to make the movement work.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The cerebellum is a comparator. Explain.

A

it compares the intended movement with the actual performance

if intention and performance match the cerebellum can go to sleep

if there is no match, the target is off, the cerebellum has to make it match, make the adjustment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Cerebellum must have what factors to make an adjustment?

A
  • corollary discharge: cerebellum must have information about the intended movement (the movement you expect to make); gets corollary discharge or internal feedback or efferent copy for the intended movement
  • reafference or external (sensory) feedback for the actual movement response; as you’re executing a movement the cerebellum is monitoring that movement and getting feedback to see if there needs to be any adjustments
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

The sensory information that the cerebellum receives is used for what?

A
  • autonomic regulation and control of motor function (including posture)
  • for the limbs and the axial musculature
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Through comparisons of external and internal feedback signals, the cerebellum is able to what?

A
  1. correct ongoing movements when they deviate from the intended course (efferent copy)
  2. modify motor programs in the CNS so that future movements attain their goals, ie. greatly involved in motor learning
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

The cerebellum receives what external (sensory) feedback?

A
  1. vestibular
    a. primary afferents: (ipsilateral)
    b. vestibulocerebellar: vestibular nuclei (bilateral)
  2. spinal cord
    a. dorsal spinocerebellar tract
    b. ventral spinal cerebellar tract
    c. cuneocerebellar tract
    d. rostrospinocerebellar tract
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the internal feedback (efferent copy) of the cerebellum?

NEED to KNOW

A
  • cerebral cortex
    a. pontocerebellar (contralateral)***

-cortex reaches the cerebellum through the PONS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the major output of the cerebellum?

A

cerebellum goes to the motor systems of the brain: primary and lateral premotor cortex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

cerebellum structure

A
  • forms a roof over the 4th ventricle
  • divided into two regions: vermis and hemispheres
  • vermis is the oldest part of the cerebellum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

The cerebellar tonsils are clinically important when there is a increase in intracranial pressure (epidural hematoma). Explain.

A
  • tonsils are located on the posterior lobe of cerebellum
  • as they herniate through the foramen magnum they put pressure on the medulla thus putting pressure on the cardio and pulmonary centers

They can:
herniate through the foramen magnum
compress the medulla
cause death

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

The surface of the cerebellum is extensively folded by what?

A

(largely) transversely running folia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

The cerebellum is composed of what 3 major lobes?

A

anterior lobe
posterior lobe
flocculonodular lobe

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What separates the anterior and posterior lobes?

A

primary fissure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What separates the focculonodular and posterior lobes?

A

posterolateral Fissure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What type of fibers form the arbor vitae ‘tree of life’?

A

white matter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What organization have functional and clinical significance?

A

flocculonodular organization

Each hemisphere is composed of an intermediate (paravermal) and lateral part.

These parts represent distinct functional subdivisions with distinct connections.
????

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the 3 functional divisions of the cerebellum?

A
  1. Vestibulocerebellum
  2. Spinocerebellum:
    has direct connections with the spinal cord
  3. Cerebrocerebellum
    has massive connections with the cortex via the basilar pons ?????
28
Q

What are the inputs into the cerebellum?

A
  • corticopontine: the lateral hemisphere is primarily connected to the pons; receives cortical input through the corticopontine and pontocerebellar system
  • spinal (limbs)
  • trigeminal (and trunk: located in the vermis
  • vestibular: has a lot of primary afferents from vestibular nuclei and it even goes into the spinocerebellum region in the vermis
  • visual and auditory: are located in the vermis

spinocerebellar tract projects primarily into the vermis and intermediate lobe

29
Q

Describe the Somatotopic Organization of Inputs to the Cerebellum.

A

Spinocerebellum

  • intermediate zone: sensory input from the limbs
  • medial zone: vermis is related to the control of the axial musculature

Cerebrocerebellar
-lateral hemisphere

Vestibulocerebellum

  • flocculus
  • nodulus
30
Q

The descending motor systems are organized into what two major fiber columns?

A

Lateral Descending System
(limb muscles)
1. lateral corticospinal
2. rubospinal

Medial (Anterior) Descending System
(axial muscles)--these are all BILATERAL input
1. anterior corticospinal
2. vestibulospinal
3. reticulospinal
31
Q

What is the cerebellar output for the spinocerebellum, cerebrocerebellum, and vestibulocerebellum?

A

spinocerebellum: axial (medial descending system) and limb (lateral descending system) musculature for motor execution
cerebrocerebellum: to areas 4 and 6 for motor planning and coordination
vestibulocerebellum: for balance and eye movements

32
Q

How is the cerebellum connected to the brainstem?

A

3 cerebellar peduncles: large axon tracts

33
Q

Describe the 3 cerebellar peduncles.

A

-superior cerebellar peduncle (connects to cerebellum to the midbrain); for the most part the OUTPUT of the cerebellum

In general, the cerebellum sends its efferents (…to cortex) through the superior cerebellar peduncle.

-middle cerebellar peduncle
(connects cerebellum to the pons); cortical INPUT through the basilar pons

-inferior cerebellar peduncle
(connects the cerebellum to the medulla); mainly INPUT

In general, the cerebellum receives its afferents through the:

  • inferior cerebellar peduncle (spinal cord & medulla)
  • middle cerebellar peduncle (pons - cortical input)
34
Q

Know the reference slide

The Inputs and Outputs of the Cerebellum Pass Through the Peduncles

A

Have to know:
-Middle Peduncle: pontocerebellar (contralateral)*** INPUT!!

Superior Peduncle	
outputs:
	a. cerebellothalamic
	b. cerbellorubal
input: 
	1. ventrospinocerebellar

rubal is the red nucleus (the other target of outputs to the cerebellum)?????

35
Q

The cerebellum has gray matter of what two types?

A
  • has a cortex (which is gray matter) which is organized into 3 distinct layers:
    1. molecular layer
    2. Purkinje cell layer
    3. granular layer

-there are 4 deep cerebellar nuclei (output):
gray matter embedded in the white matter deep to the cerebellum cortex

  1. fastigial
  2. emboliform
  3. globose
  4. dentate

emboliform and globose are the interposed nuclei (won’t ask about this)

36
Q

What are the 5 types of neurosn found in the cerebellum?

A

1) granular cells: found in the deepest layer (granular cell layer); their axons run to the surface and split running parallel to the folia
2: Purkinje cells: project long inhibitory axons that go to the deep cerebellar nuclei

  1. stellate cells
  2. basket cells
  3. golgi cells

will only ask about the 1st two layers and not 3-5 which are all inhibitory

37
Q

Describe Purkinje cell.

A
  • has a fan shaped dendritic organization that have a perpendicular orientation to the folia
  • looks like a Chinese fan????

Purkinje cells project to the deep cerebellar nuclei* and are the sole (inhibitory) output of the cortex.

SO ALL OUTPUT (inhibitory) from the cerebellar cortex goes through the purkinje fibers

exception is the Purkinje cells in the flocculonodular lobe which project t o the 4 vestibular nuclei which can be thought of as the deep cerebellar nuclei

38
Q

What are the three types of afferents that come into the cerebellum/ conduct nerve impulses to the cerebellum?

A
  1. aminergic fibers (modulatory)
    - they change the excitability of different modules of the cerebellum
    - cerebellum can go to sleep if it is not doing anything
  2. mossy fibers (excitatory)
  3. climbing fiber (excitatory)
39
Q

Aminergic fibers come from what sources and where do they terminate?

A

Two sources

  1. raphe nuclei: serotonin
  2. locus coeruleus: norepinephrine

Fibers terminate in all layers of cortex.

They modulate cerebellar excitability.

REFERENCE SLIDE

40
Q

Climbing fibers come from what sources and where do they terminate?

A
  • come from inferior olivary complex (ONLY ONE SOURCE) ; axons from these cells go to the contralateral side to the cerebellum
  • climbing fibers wrap around the soma and climb the dendrites of Purkinje cells making numerous excitatory contacts
  • climbing fiber terminations looks just like the dendritic tree of the Purkinje

very close relationship between axon termination of the climbing fibers and the purkinje neurons; they are not superimposed

41
Q

Each Purkinje cells receives input from how many climbing fibers? How many synapses will climbing fibers make on Purkinje cells?

A

Each Purkinje cells receives input from 1 climbing fiber.

a single climbing fiber synapses on 1-10 Purkinje cells

climbing fibers run perpendicular to the folia

climbing fibers provide powerful excitatory and low frequency input (1 spike/s)

climbing fiber input is “all-or-nothing,” (ie., a single action potential in a climbing fiber evokes a complex spike in the Purkinje cell)

42
Q

The Climbing fiber input into a Purkinje cells is one of the most powerful in the nervous system. Explain this.

A

A single action potential in a climbing fiber evokes a ‘complex spike’ and a large Ca2+ influx.

they underlie the plasticity (cerebellar learning is somehow involved with climbing fibers and the use of calcium to modify synapses)

43
Q

Most climbing fibers also send collaterals to which nuclei?

A

the deep cerebellar nuclei

44
Q

What is the major type of input into the cerebellum?

A

Mossy fibers

-all other input coming from the pons, brainstem, spinal cord, reticular etc. form mossy fiber

it is the MAJOR INPUT to the cerebellum

45
Q

Describe Mossy fibers.

A
  • they synapse with granular cells in the granular cell layer that will then synapse on Purkinje cells
  • has to be a massive amount of these fibers firing at the same time at a high frequency
  • provides a high frequency (50-100 spikes/s), excitatory input that must be summated to cause spiking of the Purkinje cells
46
Q

Why do you need summation of Mossy fibers?

A
  • to excite purkinje cells
  • input coming from a single parallel Mossy fiber is minor
  • Simple Spike will be evoked by spatiotemporal summation of Mossy Inputs
47
Q

How do Mossy fibers indirectly influence many Purkinje cells? What is their type of influence

When you have intersections of mossy and climbing fiber, what happens?

A

Mossy fibers enter into the granular cell layer then synapse onto the granule cells. The granule cells axons will then go up into the molecular layer and form parallel fibers that will run through many Purkinje cells.

Granule cells are EXCITATORY

-there is coincidence which is what the cerebellum will start processing

????

  • Climbing fibers are perpendicular to the folia.
  • Granule cell axons split parallel to folia.
48
Q

Inhibitory (gabanergeric) interneurons integrate the excitatory inputs into Punkinji cells. Where are these cells found?

A

These cells are found in the granular and molecular layers.

49
Q

What are the 3 deep cerebellar nuclei?

A
  • fastigial: closest to the nuclei; directly underneath the vermis
  • interposed nuclei
  • dentate nuclei: largest of the 3
50
Q

Purkinje cells go where????

A

???

vermis: fastigial
intermediate: interposed
cerebrocerebellum: dentate

flocculonodular lobe go to all four vestibular nuclei

51
Q

What is the largest part of the cerebellum?

A

corticocerebellum

1. afferents
2. efferents 
3. lesions
52
Q

The cerebellum receives its MAJOR input from the cortex which is relayed through the pons.

The corticopontine tract originates primarily from where?

A
  1. premotor cortex (area 6)
  2. motor cortex (area 4)
  3. somatosensory cortex (areas 3, 1, 2)
  4. higher order somatosensory cortex (area 5)
53
Q

Compare the size of the corticopontine tract to the corticospinal tract.

A

CPT: 10 million fibers
CST: 1 million fibers

54
Q

Where are the corticopontine fibers located in the crus cerebri and where to they terminate?

A

Corticopontine fibers pass through the cerebral peduncle on either side of the corticospinal tract

Corticopontine fibers terminate in nuclei found in the basile pons

pontine nuclei form the white (fiber stain) matter laced between fiber tracts

55
Q

Where do the corticopontine fibers cross?

A

Pontocerebellar fibers cross in the pons and reach the cerebellum via the middle cerebellar peduncle

56
Q

Efferents from pontine nuclei form mossy fibers terminating primarily in the contralateral cerebrocerebellum

A

???????

57
Q

Principle Efferent Connection of the DENTATE Nucleus*

A
  • decussate go to the VL of thalamus then to area 4 and 6
  • A small portion of dentate efferents synapse in the red nucleus (parvocellular part) before being relayed to thalamus & cortex

???

58
Q

Where will the contralateral fibers synapse?

A

Cerebellar signs are usually ipsilateral because the decussations of the corticopontine-cerebellar tract and the cerebellothalamic tract .

59
Q

Principle Efferent Connections of the INTERPOSED Nucleus To the Cortex & Red Nucleus

A

-they go to the magnocellular part of the nucleus of the rubrospinal tract

60
Q

Where do the efferents from the fastigial nucleus go and what are their effects?

A

1) via inferior cerebellar peduncle

2) targets
a. vestibular nuclei (vestibulospinal pathways)
b. reticular formation (reticulospinal pathways)

3) effects
a. posture
b. automatic movements (e.g., locomotion)

61
Q

What occurs with lesions of the cerebellar cortex? What is the triad of cerebellar dysfunction?

A
  • there are delays of initiation of movement
    1) Hypotonia (loss of cerebellar facilitation of motor cortex)

2) Disequilibrium (loss of balance)
a. trunk ataxia
b. limb ataxia

3) Dyssynergia (loss of coordinated muscle activity)
a. ataxia
b. dysmetria: when you try to touch your nose you either under or over shoot
c. decomposition or fragmentation of movement
d. dysarthria (scanning or robotic speech)
e. dysdiadochokinesia (pronation/supination Dr. Graf talked about)
f. intentional tremor
g. nystagmus

62
Q

Dystonia, hyper-reflexia and clonus

A

????

63
Q

Describe ‘Flocculonodular’ & ‘Anterior Lobe’ Syndromes”* (disturbances in equilibrium).

A

seen in alcoholics where they have disequilibrium

gait ataxia: limbs are spread apart and they teetering back and forth as though they are drunk

Patient teeters back, forth & sideways

Wide-based gait (gait ataxia).

  • degeneration of the anterior lobe is characteristic of alcoholics and thiamine deficiency
    ?????
64
Q

Describe the finger-to-nose test.

A

Patient cannot direct finger accurately to nose with eyes close.

a. hypometria: under measured
b. hypermetria: over measured

Patient cannot rapidly repeat
alternating movements
(adiadochokinesia).

65
Q

Patients with vermal damage can be differentiated from patients with lesion of the dorsal columns by the Romberg Sign. What is the romberg sign?

A

Vermal lesion: patients loose balance with their eyes open falling towards the lesion.

Dorsal column lesion – patients loose balance with their eyes closed; often occurs in syphillis

66
Q

What is Fredrick’s Ataxia?

What are symptoms of it?

A

An inherited autosomal recessive disease resulting in low levels of frataxin required for mitochondrial electron transport.

Symptoms:

a) muscle weakness in extremities
b) ataxia and loss of coordination and dysmetria
c) dysarthria and dysphagia

67
Q

The cerebellum is involved in what type of motor learning?

A

error-based motor learning

Chika- SF2 (63 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions