L13 Cerebellum

Question 1

Cerebellum help in

Answer 1

1- timing of motor activities
2- rapid smooth progression from one muscle movement to the next.
3- It also helps to control intensity of muscle contraction when the muscle load changes
4- controlling necessary instantaneous interplay between agonist and antagonist muscle groups.

So Coordinate voluntary movement
Nonverbal learning and memory
And its Called: silent area of the brain.

Question 2

The cerebellum is especially vital
during:

Answer 2

rapid muscular activities
such as;
- running,
- typing,
- playing the piano,
- talking.
—

Question 3

Loss of cerebellum can cause

Answer 3

total incoordination

Question 4

Part of cerebellum controlling equilibrium

Answer 4

vestibular system

flocculonodular
فيه اسم ثاني ورا

Question 5

Functional division of cerebellum

Answer 5

1- vestibulocerecellum ( flocculonodular)
2- spinocerebeelum ( vermis , intermediate zone )
3-Cerebrocerebellum ( lateral zone )

Question 6

Vestibulocerebellum

Answer 6

Input:
Vestibular nuclei

Function:
Regulate and balance eye and posture movement ,equilibrium

Damage:
Inability to stand upright
Cerebellar nystagmus

Question 7

Spinocerebellum

Answer 7

Input :
Spinal cord

Function:
-Lateral portion (هو نفسه له جزأين يعني غير اللترال الاساسيه )
Mov. Of distal muscle ( gross mov. during walking )

-vermis
Movement of proximal muscles

Damage:
Overshoot ( tension tremors )
Impaired gait

Question 8

Cerebrocerebellum

Answer 8

Input :
Cerebral cortex ( relayed in pons )

Function:
Planning and timing of sequential movements
speech

Damage :
Ataxia
Incoordination Of complex porpusful mov.
Failure of smooth progression of movement

Question 9

representations of the different parts of the
body in cerebellum is seen in

Answer 9

vermis and intermediate zones

Question 10

The axial portions of the body represented in
lie in the ………………………….. of the cerebellum,
whereas The limbs and facial regions lie in the ………………..

Answer 10

vermis

intermediate zones.

Question 11

large……………………of cerebellar hemispheres do not have topographical representations of the body.

Answer 11

lateral portions

Question 12

These areas of the cerebellum receive their input signals almost exclusively from the cerebral cortex, especially from:

• premotor areas of the frontal cortex and
• somatosensory and other sensory association areas of the
  parietal cortex.

Answer 12

lateral part of cerebellum

((play important roles in planning and coordinating the body’s rapid sequential muscular activities that occur one after another within fractions of a second))

Question 13

Afferent Pathways from other parts of the brain to cerebellum:

Answer 13

1. Corticopontocerebellar pathway
2. Olivocerebellar tract
3. Vestibulocerebellar fibers
4. Reticulocerebellar fibers

Question 14

Afferent pathways from the periphery
To cerebellum

Answer 14

1- The dorsal spinocerebellar tract —
2- The ventral tract

Question 15

signals transmitted in the dorsal spinocerebellar tracts come mainly from:

Answer 15

• the muscle spindles
• and to a lesser extent from other somatic receptors throughout the body, such as:
  Golgi tendon organs,
  —large tactile receptors of the skin,
  —*joint receptors.

—All these signals apprise the cerebellum of the momentary status of:
(1) muscle contraction
(2) degree of tension on the muscle tendons,
(3) forces acting on the surfaces of the body
(4) positions and rates of movement of the parts of the body,

Question 16

The ventral spinocerebellar tracts receive less information from the
peripheral receptors. —
Instead, they are excited mainly by:

Answer 16

motor signals arriving in the anterior horns of the spinal cord from the
brain through:

— (1) the corticospinal & rubrospinal tracts
(2) the internal motor pattern generators in the cord itself.

Question 17

ventral fiber pathway tells the cerebellum which motor signals
have arrived at the anterior horns; this feedback is called the

Answer 17

efference copy of the anterior horn motor drive

Question 18

the most rapid conduction
in the central nervous system.

Answer 18

spinocerebellar pathways can

120 m/sec

Question 19

All the deep cerebellar nuclei
receive signals from two sources:

Answer 19

(1) the cerebellar cortex
(2) the deep sensory afferent tracts to the cerebellum.

Question 20

input signal arrives in the cerebellum, it divides and goes
in two directions:

Answer 20

(1) directly to one of the cerebellar deep nuclei and
(2) to a corresponding area of the cerebellar cortex overlying the
deep nucleus.

Question 21

all input signals that enter the
cerebellum eventually end in the deep nuclei in the form of

Answer 21

—-initial excitatory signals —
-followed a fraction of a second later by inhibitory signals.

Question 22

general plan of the major efferent pathways

Answer 22

1. A pathway that originates in the midline of the cerebellum (the vermis))
   — ((association with the equilibrium apparatus and brain stem vestibular nuclei to control equilibrium))
2. A pathway that originates in the intermediate zone of the cerebellar hemisphere
   —((helps to coordinate mainly the reciprocal contractions of agonist and antagonist muscles
   in the peripheral portions of the limbs))
3. A pathway that begins in the cerebellar cortex of the lateral zone of the cerebellar hemisphere
   ((helping coordinate sequential motor activities initiated by the cerebral cortex))

Question 23

The climbing fibers originate from the

Answer 23

inferior olives of the
medulla.

Question 24

action potential in climbing fiber of of cerebellum is called

Answer 24

complex spike.

Question 25

mossy fiber input to the Purkinje cell type of its action potential?

(multiple sources: from the higher brain, brain stem, and spinal cord ) طالع من

Answer 25

simple spike

Question 26

Direct stimulation of the deep nuclear cells by both the climbing and the mossy

Answer 26

fibers excites them

By contrast, signals arriving from the Purkinje cells ((inhibit them))**

Question 27

Importance of damping in cerebellum

Answer 27

stop the muscle movement from overshooting

اول شيء تحفيز سريع بعدها فيدباك يثبط العملية لان cerebellum بطبيعته favor excitation

Question 28

Inhibitory cells of cerebellum

Answer 28

Purkinje cells,
basket cells
stellate cells.

Question 29

typical function of the cerebellum is to help provide

Answer 29

rapid turn-on signals for the agonist muscles and simultaneous reciprocal
turn- off signals for the antagonist muscles at the onset of a movement.

—Then on approaching termination of the movement, the cerebellum is mainly responsible for timing and executing the turn-off signals to the agonists and turn-on signals to the antagonists.

Question 30

Cerebellar disorders

Answer 30

Dysdiadochkinesia
Ataxia
Nystagmus
Intention tremor
Slurred speech
Hypotonia

Question 31

Archicerebellum function

Answer 31

Body equilibrium
Eye movement

Question 32

Paleocerebellum function

Answer 32

Muscle tone
Gait

Question 33

Neocerebellum function

Answer 33

Planning and initiation of movement
Regulate fine limb movement

Question 34

Limbic Ataxia —
— Hypotonia
— Dysarthria
Dysdiadochokinesia
— Intention Tremor

Damage to

Answer 34

Neocerebellum

Question 35

Truncal & Gait ataxia
Damage to

Answer 35

Paleocerebellum

Question 36

Nystagmus and gait dysfunction damage to

Answer 36

Archicerebellum

Question 37

Two of the most important symptoms of cerebellar disease are

Answer 37

dysmetria and ataxia .

Question 38

lesions in the spinocerebellar
tracts led to

Answer 38

Dysmetria and ataxia

Question 39

Past pointing means

Answer 39

moves the hand or some other moving part of the body
beyond the point of intention.

past pointing is actually a manifestation of dysmetria

Question 40

Hypotonia Due to

Answer 40

Loss of the deep cerebellar nuclei, particularly of the
dentate and interposed nuclei,

loss of cerebellar facilitation

Question 41

Dysarthria (failure of progression)

Answer 41

§ some syllables loud,
§ some weak,
§ some held for long intervals,
§ some held for short intervals,

Question 42

Failure of progression - Dysdiadochokinesia

Answer 42

fails to predict where the different parts of the body will be at a given time,

jumbled movements
may begin much too early or much too late,

Question 43

oscillate with first overshooting the
mark and then vibrating

Answer 43

intention tremor or an action tremor,

and it results from cerebellar overshooting
and failure of the cerebellar system to “damp” the motor movements.

Question 44

tremor of the eyeballs that occurs usually when one
attempts to fixate the eyes on a scene to one side of the head;

Answer 44

Cerebellar nystagmus

failure of damping flocculonodular lobes of th cerebellum are damaged