cerebellar function

Question 1

Define dysmetria

Answer 1

• inability to accuretely control the range of movement in muscular acts

Question 2

define hypermetria

Answer 2

• an ataxic muscle disorder characterized by overreaching the intended object or goal

Question 3

define ataxia

Answer 3

• loss in coordination of the muscles, esp of extremities

Question 4

define dysdiadochokinesia

Answer 4

• impairment of the ability to make movements exhibiting a rapid change of motion that is caused by cerebellar dysfunction

Question 5

define dysarthria

Answer 5

• any of certain disorders of articulation, such as stammering or stuttering, caused by nerve deficit

Question 6

define intention tremor

Answer 6

a tremor that occurs when voluntary movement is made

Question 7

define nystagmus

Answer 7

a congenital or acquired persistent, rapid, involuntary and oscillatory movment of the eyeball, usually from side to side

Question 8

define hypotonia

Answer 8

• diminished resistance to passive movement

Question 9

define synergy

Answer 9

cooperative action of two or more muscles, nerves or the like

Question 10

define asynergia

Answer 10

defective coordination between parts, as muscles or limbs, that normally act in unison

Question 11

define decomposition of movement

Answer 11

deterioration of controlled movements

Question 12

define pendular knee jerk

Answer 12

results of insult to the cerebellum; not brisk, but involve less damping of the limb movement than is normally observed - may swing forward and backward several times (like a pendulum)

Question 13

define titubation

Answer 13

tremor of entir trunk or head during stance and gait

Question 14

define static tremor

Answer 14

tremor that occurs when muslces is at rest

- seen in parkinsons

Question 15

describe input and output of vestibulocerebellum

Answer 15

• INPUT =
• -> primary afferents from vestibular labrynth and nuclei
• -> indirect visual input from superior colliculi and striate cortex
• OUTPUT =
• -> mainly to vestibular nuclei and fastigial nucleus

Question 16

describe the function of the vestibulocerebellum

Answer 16

• control of eye movements and position of head

- regulate gait and posture especially through vestibulospinal reflexes

Question 17

describe a lesion/disease of vestibulocerebellum

Answer 17

RESULT IN:

• -> ataxic gait (wide-based stance, legs move irregularly while walking, but accurate wile laying down)
• -> eye movement disorders including a type of cerebellar nystagmus

Question 18

describe the input/output of spinocerebellum- VERMIS PORTION

Answer 18

INPUT:
–> somatosensory info from spinal cord (axial and proximal body parts)
–> vestibular inputs
–> facial, visual and auditory input to posterior lobe only
OUTPUT:
–> via fastigial nucleus to medial motor systems, vestibular nucleus and reticular formation
–> also motor cortex

Question 19

Describe the function of the spinocerebellum- VERMIS PORTION

Answer 19

• Regulates AXIAL and PROXIMAL musculature

- concered with ONGOING MOTOR EXECUTION and regulation of MUSCLE TONE

Question 20

describe a lesion/disease to the spinocerebellum- VERMIS PORTION

Answer 20

RESULTS IN:

• -> decreased muscle tone in proximal and axial musculature
• -> problems with ongoing motor execution

Question 21

Describe the inputs/outputs of the spinocerebellum- PARAVERMAL regions

Answer 21

INPUT:
–> somatosensory info from distal body parts (limbs)
–> input from primary and somatic sensory cortex
OUTPUT:
–> via inopositus to lateral motor systems
–> RED nucleus and also to motor cortex

Question 22

FUNCTION of Sspinocerebellum- paravermal regions

Answer 22

• REGULATES DISTAL MUSCLES

Question 23

Lesion/disease to spinocerebellum-paravermal region

Answer 23

RESULTS IN:

• -> IPSILATERAL TO LESION
• -> HYPOTONIA

Question 24

Describe input and output of cerebrocerebellum (aka pontocerebellum)

Answer 24

INPUTS:
–> corticoafferents via pontine nuclei
OUTPUTS:
–> DENTATE nucleus to ventral lateral nucleus of thalamus and red nucleus
–> Ventral lateral thalamus then projects to premotor and primary motor cortex

Question 25

describe the function of the cerebrocerebellum

Answer 25

- Role in preparation for movement - especially important for multi-joint movements - affect on patients ability to judge elapsed time in non-motor tasks

Question 26

Lesion/disease to cerebrocerebellum

Answer 26

RESULTS IN: - -> delays in initiating and terminating movements - -> problems with multi-joint movements - -> affect on patients ability to judge elapsed time in non-motor tasks (may actually show improvement with eyes closed

Question 27

Purkinje cells

Answer 27

- Only cell to project oUT OF CEREBELLAR CORTEX

Question 28

granule

Answer 28

- only excitatory cells in cerebellar cortex

Question 29

golgi

Answer 29

- affect dendritic input to purkinje cells by inhibiting granule cells

Question 30

stellate cells

Answer 30

affect dendritic intergration of purkinje cells

Question 31

basket

Answer 31

makes inhibitory synapses near initial segment of purkinje cell axon

Question 32

Define MOSSY FIBER

Answer 32

- Originate in spinal cord, vestibular nuclei, brianstem reticular formation, deep pontine nuclei - Effect on input to purkinje cell - -> DOESN"T DIRECTLY SYNAPSE on purkinje cell - -> sends excitatory signals to granule and golgi cell dendrites - -> granule cells then become parallel fibers, which makes excitatory synapses on purkinje cells

Question 33

Define climbing fibers

Answer 33

- originate in inferior olibary nuclei - Effect of input to purkinje cell = each blimbing fiber ONLY SYNPASES ON ONE PURKINJE CELL, but that one cell makes MANY EXCITATORY SYNAPSES on the purkinje cell

Question 34

Alcoholism

Answer 34

- Thiamine (vitamin B1) deficiency associated with long-term alcoholism - causes atrophy of anterior lobe of cerebellum - pts have difficulty walking and with leg control in generaly - control of arms and legs are less affected

Question 35

multiple sclerosis

Answer 35

- demyelination of CNS - cerebellar systems commonly affected in patients with long term chronic MS - LESIONS may be in cerebellum itself, cerebellar peduncles or brainstem pathways afferent or efferent to the cerebellum

Question 36

Genetic disease/FREDERICH ATAXIA

Answer 36

- recessive inherited progressive spinocerebellar ataxia - caused by an expanded repetition of the trinucleotide GAA in a gene on chromosome 9 - may also be inherited dominantly due to different expanded triplet repeat (CAG)

Question 37

NEOPLASTIC DISEASE

Answer 37

- primary tumors/metastic disease