ME03 - Motor System 2 - Cerebellum, Basal Ganglia

Question 1

Also called the little brain
Helps control the rate, range, force, and direction
of movements (SYNERGY)
o sequences motor activities
o monitors and makes corrective adjustments in motor activities while they are being executed silent area of the brain

Answer 1

Cerebellum

Question 2

Electrical excitation does not cause any sensation. True or False?

Answer 2

TRUE

Question 3

Damage does not produce paralysis. True or False?

Answer 3

TRUE

Question 4

Where is Cerebellum located?

Answer 4

Located dorsal to the pons and medulla and protrudes from under the occipital lobes

Question 5

3 Lobes of Cerebellum

Answer 5

ANTERIOR, POSTERIOR, FLOCCULONODULAR

Question 6

Crosswise folds in the Cerebellar Cortex

Answer 6

Folia

Question 7

Lie deep beneath the folded mass of cerebellar cortex

Answer 7

Deep Cerebellar Nuclei

Question 8

Nuclei of Cerebellum from Medial to Lateral

Answer 8

DENTATE, EMBOLIFORM, GLOBOSE, FASTIGIAL

Question 9

What are the Brainstem Attachments of Cerebellum

Answer 9

superior cerebellar peduncles to MIDBRAIN
middle cerebellar peduncles to PONS
inferior cerebellar peduncles to MEDULLA OBLONGATA

Question 10

Contains a somatotopic map of the body surface

Answer 10

VERMIS and INTERMEDIATE ZONE
o Axial portions of the body lie in the vermis

o Limbs and facial regions lie in the intermediate zones

Question 11

Lateral portions of cerebellar hemispheres do not have topographical representations. True or False?

Answer 11

TRUE

Question 12

Function of the lateral portion of cerebellar hemisphere

Answer 12

o Receive input signals exclusively from cerebral cortex
o Plays important roles in planning and coordinating the body’s rapid sequential muscular activities

Question 13

3 Layers of Cerebellar Cortex

Answer 13

Granular Layer | Purkinje Cell Layer | Molecular Layer

Question 14

Innermost layer that contains granule cells, Golgi type II cells and glomeruli

Answer 14

Granular Layer

Question 15

Middle layer that contains inhibitory Purkinje cells

Answer 15

Purkinje Cell Layer

Question 16

Outermost layer that contains stellate and basket cells, dendrites of Purkinje and Golgi type II cells and parallel fibers (axons of granule cells)

Answer 16

Molecular Layer

Question 17

2 Types of Fibers that are known as Excitatory Cerebellar Inputs

Answer 17

Climbing Fibers | Mossy Fibers

Question 18

o Originate in the INFERIOR OLIVE
o Demonstrate complex spikes
_ Action potentials beginning with a strong spike and followed by a trail of weakening secondary spikes
o Function in conditioning Purkinje cells (motor learning)

Answer 18

CLIMBING FIBERS

Question 19

o Form the bulk of the input, originating in the cortico-, vestibulo-, reticulo- and spinocerebellar tracts_o demonstrate SIMPLE SPIKES
Much weaker short-duration action potentials in Purkinje cells

Answer 19

MOSSY FIBERS

Question 20

What are the Different Afferent Pathways to the Cerebellum

Answer 20

Pontocerebellar System | Olivocerebellar Projections | Spinocerebellar Fibers | Reticulocerebellar Fibers | Vestibular Fibers

Question 21

o Largest afferent projections
o Originate from the basilar pontine nuclei

Answer 21

PONTOCEREBELLAR SYSTEM

Question 22

Originate from the inferior olivary nuclei

Answer 22

OLIVOCEREBELLAR PROJECTIONS

Question 23

Originate in spinal cord or medulla

Answer 23

SPINOCEREBELLAR FIBERS

Question 24

Originate from brainstem

Answer 24

RETICULOCEREBELLAR FIBERS

Question 25

Originate from vestibular nuclei and vestibular apparatus

Answer 25

VESTIBULAR FIBERS

Question 26

What are the Cells seen in Cerebellum

Answer 26

Purkinje cells | Granule cells | Golgi Type II Cells | Stellate Cells | Basket Cells | Glomerulus

Question 27

o central neurons with fan-shaped dendritic trees o always inhibitory with GABA as its neurotransmitter

Answer 27

Purkinje cells

Question 28

o smallest and most numerous neurons in the brain o parallel fibers are axons of granule cells o excitatory input from mossy fibers which use glutamate as its neurotransmitter

Answer 28

Granule cells

Question 29

o small interneurons with numerous arborizations o inhibitory in function

Answer 29

Golgi Type II Celks

Question 30

o inhibitory star-shaped cells found in superficial cerebellum

Answer 30

Stellate Cell

Question 31

o inhibitory cells whose axons form baskets around Purkinje fibers and are found in deep cerebellar layers

Answer 31

Basket Cells

Question 32

o complex of synapses having a mossy fiber at its core o synapsing with axons of Golgi type II neurons and dendrites of granule cells

Answer 32

Glomerulus

Question 33

Modulates Purkinje cell output

Answer 33

Cerebellar Interneurons

Question 34

All of the cerebellar interneurons are inhibitory EXCEPT _______________

Answer 34

Granule Cells

Question 35

Have excitatory input to basket cells, stellate cells, Golgi II cells, and Purkinje cells

Answer 35

Granule Cells

Question 36

Inhibits Purkinje cells (via parallel fibers)

Answer 36

Basket cells and Stellate cells

Question 37

Inhibit granule cells, thereby reducing their excitatory effect on Purkinje cells

Answer 37

Golgi II cells

Question 38

Only output of the cerebellar cortex

Answer 38

Purkinje Cells

Question 39

Output is always inhibitory, using _______________ as NT

Answer 39

GABA

Question 40

Inhibitory output modulates the output of the cerebellum and regulates rate, range, and direction of movement (synergy). True or False

Answer 40

TRUE

Question 41

Projects to fastigial nucleus, vestibular nucleus and reticular formation

Answer 41

Vermis

Question 42

Project to globose and emboliform nuclei (interposed nuclei)

Answer 42

Intermediate Zone

Question 43

Project to the dentate nucleus, ventral anterior thalamic nuclei and cerebral cortex

Answer 43

Lateral Hemispheres

Question 44

Follow the Cerebellar Pathway

Answer 44

Cortex >> Pons* >> Cerebellum >> Dentate nucleus* >> Red Nucleus >> Thalamus >> Corticospinal tract

Question 45

o consists of the small flocculonodular lobes o for control of balance and eye movement

Answer 45

Vestibulocerebellum

Question 46

Consists of lateral zones of cerebellar hemispheres For planning and initiation of movement

Answer 46

Cerebrocerebellum

Question 47

o consists of vermis and intermediate zones o for control of rate, force, range, and direction of movement (synergy)

Answer 47

Spinocerebellum

Question 48

o During nearly every movement, certain muscles must be rapidly turned on and then quick turned off

Answer 48

TURN ON/TURN OFF FUNCTION

Question 49

TURN ON/TURN OFF FUNCTION is made possible by

Answer 49

Made possible by interplay of mossy and climbing fibers and Purkinje cells

Question 50

What fibers are involved in Motor Learning?

Answer 50

CLIMBING FIBERS. Climbing fibers modify sensitivity to parallel fiber input o when mismatch between anticipated result of movement and its actual result occurs, climbing fiber input is more vigorous o as movement is practiced, mismatch declines gradually

Question 51

o During any movement, momentum develops and must be overcome to stop the movement o Appropriate learned, subconscious signals from spinocerebellum stop the movement precisely at the intended point

Answer 51

Damping Function

Question 52

Patient with cerebellar lesion assumes unsteady stance and reeling gait (like a drunk person)

Answer 52

Ataxia

Question 53

How does a Patient with Ataxia compensate?

Answer 53

To compensate, he assumes a broad-based stance and a broad-based gait

Question 54

Failure to meter the contractions that set the distance of motion

Answer 54

Dysmetria

Question 55

Inability to perform rapid alternating movements

Answer 55

Dysdiadochokinesia

Question 56

Failure of a movement to be terminated at a proper time

Answer 56

Past Pointing

Question 57

Difficulty in maintaining position against sudden unexpected displacement

Answer 57

Overshooting

Question 58

Slowness and slurring of speech

Answer 58

Dysarthria

Question 59

Volume of voice varies from low to high from peak to peak

Answer 59

Scanning Speech

Question 60

Tremor of intentionally maintained head or trunk posture or of a limb suspended in front of the body

Answer 60

POSTURAL, POSITIONAL or STATIC TREMOR

Question 61

Unsteady oscillations of the head or trunk

Answer 61

TIUTIBATION

Question 62

o Tremor as a limb approaches its target o Results from cerebellar overshooting and failure of the cerebellar system to "damp" the motor movements

Answer 62

INTENTION, END-POINT or KINETIC TREMOR

Question 63

Jerkiness of eye movement o rapid, tremulous movements of the eyes rather than steady fixation

Answer 63

Nystagmus

Question 64

What is affected in Nystagmus?

Answer 64

Nystagmus is due to failure of damping by the cerebellum Occurs especially when the flocculonodular lobes of the cerebellum are damaged

Question 65

Decreased tone of the peripheral body musculature on the side of the cerebellar lesion

Answer 65

Hypotonia

Question 66

What is affected in Hypotonia?

Answer 66

Results from loss of cerebellar facilitation of the motor cortex and brain stem motor nuclei

Question 67

Extremity tested swings to and fro several times like a pendulum after eliciting the reflex seen in HYPOTONIA

Answer 67

Pendulous reflexes

Question 68

What are the Different Cerebellar Syndromes

Answer 68

ANTERIOR (ROSTRAL) VERMIS SYNDROME_- involves the anterior cerebellar lobe ; o ataxia of the lower limbs only POSTERIOR (CAUDAL) VERMIS SYNDROME - involves the flocculonodular and posterior lobes ; o axial ataxia without extremity ataxia CEREBELLAR HEMISPHERE SYNDROME - cerebellar signs lateralized to one half of the body PANCEREBELLAR SYNDROME_- bilateral cerebellar signs due to involvement of all cerebellar lobes

Question 69

Deep cerebral nuclei involved in motor control modulates thalamic outflow to the motor cortex to plan and execute smooth movements demonstrates programming functions o generate basic patterns of movement in response to cues from cortical association areas

Answer 69

Basal Ganglia

Question 70

Components of Basal Ganglia

Answer 70

Globus Pallidus | Putamen | Caudate Nucleus | Subthalamic Nucleus of Substantia Nigra Globus Pallidus x Putamen = Lentiform Nucleus Putamen x Caudate Nucleus = Striatum Lentiform Nucleus + Striatum = Corpus Striatum CORPUS STRIATUM + SUBTHALAMIC NUCLEUS OF SUBSTANTIA NIGRA = BASAL GANGLIA

Question 71

NT used in connections between striatum and substantia nigra

Answer 71

Dopamine

Question 72

Dopamine in relation to Basal Ganglia Pathways

Answer 72

o inhibitory on the indirect pathway (D2 receptors) o excitatory on the direct pathway (D1 receptors) o overall action is excitatory

Question 73

Responsible for the COGNITIVE CONTROL OF MOTOR ACTIVITY o most of our motor actions occur as a consequence of thoughts generated in the mind

Answer 73

CAUDATE NUCLEUS

Question 74

Controls the speed and size of movement

Answer 74

Basal Ganglia

Question 75

Locus for Spatial Coordination

Answer 75

Posterior Parietal Cortex

Question 76

TIMING AND SCALING FUNCTIONS are lost with lesions in the?

Answer 76

Basal Ganglia, specifically CAUDATE NUCLEUS

Question 77

snake-like or writhing movements of the hand and arm or face result from lesions of the GLOBUS PALLIDUS

Answer 77

Athetosis

Question 78

flailing movements of the extremities result from lesions to the SUBTHALAMIC NUCLEUS OF LUS

Answer 78

Hemiballismus

Question 79

brief, irregular, non-purposeful movements that are vaguely comparable to dancing result from lesions to the CORPUS STRIATUM (specially on caudate nucleus)

Answer 79

Chorea

Question 80

Results from widespread destruction of the dopaminergic cells in the substantia nigra

Answer 80

Parkinson's Disease

Question 81

Manifestations of Parkinson's Disease

Answer 81

o cogwheel rigidity o resting pill-rolling tremor o slowness or difficulty in initiating movement (bradykinesia, akinesia) o postural instability (shuffling or FESTINATING gait)

Question 82

Autosomal dominant genetic disorder caused by CAG trinucleotide repeats o displays ANTICIPATION with succeeding generations

Answer 82

Huntington's Disease

Question 83

Characteristics of Huntington's Disease

Answer 83

Characterized by flicking movements in individual muscles (chorea) o leads to progressive severe distortional movements

Question 84

Huntington's Disease is caused by the depletion of what neurotransmitters?

Answer 84

Depletion of GABA and acetylcholine from many areas of the brain