Basal Ganglia and Cerebellum

Question 1

Basal Ganglia Roles

Answer 1

multiple roles in the nervous system and include fine-tuning movements, reward functions, cognition, and memory

Question 2

Basal Ganglia Regions

Answer 2

subcortical regions, including the putamen, caudate, nucleus accumbens, globus pallidus (interna and externa), the subthalamic nucleus, and substantia nigra

Question 3

Basal Ganglia - other terminologies for regions

Answer 3

striatum: caudate, nucleus accumbens, and putamen
lenticular nucleus: putamen, globus pallidus (has the external and internal segments)

Question 4

striatum

Answer 4

caudate, nucleus accumbens, and putamen

Question 5

lenticular nucleus

Answer 5

putamen, globus pallidus (external and internal segments)

Question 6

Basal ganglia image

Answer 6

Question 7

Direct Pathway Net Effect

Answer 7

increase (or initiate and maintain) movement
DISINHIBITS the thalamus, which facilitates the EXCITATORY thalamocortical pathway

Question 8

Direct Pathway - primary neuron receptors

Answer 8

D1 receptors

Question 9

Direct Pathway

Answer 9

cortex projections travel to the putamen which sends inhibitory projections to the globus pallidus interna (GPi) and substantia nigra reticulatum (SNr). The GPi/SNr, in turn, sends inhibitory outflow to the thalamus

Question 10

Indirect Pathway - net effect

Answer 10

suppress movement.
activity from indirect pathway excites the GPi/SNr which INHIBITS the thalamocortical pathway

Question 11

Indirect Pathway primary neuron receptor

Answer 11

D2 receptors

Question 12

Indirect Pathway

Answer 12

cortex projections travel to the putamen, which sends inhibitory projections to the globus pallidus externa (GPe), where inhibitory projections then extend to the subthalamic nucleus (STN), with the result of disinhibiting the STN. STN, in turn, has excitatory projections to the GPi

Question 13

Hypokinetic movement disorders

Answer 13

due to REDUCED activity in the DIRECT pathway

Question 14

hyperkinetic movement disorders

Answer 14

due to REDUCED activity in the INDIRECT pathway

Question 15

Parkinson’s disease presentation

Answer 15

rigidity, masked facies, and resting pill-rolling tremor due to loss of dopaminergic neurons in the substantia nigra

Question 16

lesions to substantia nigra

Answer 16

can cause parkinsonism

Question 17

hemiballismus

Answer 17

rapid violent uncontrolled flailing movements of an extremity (usually the arm), classically associated with lesions of the subthalamic nucleus

Question 18

lesions of subthalamic nucleus caused by

Answer 18

hemiballismus

Question 19

loss of dopaminergic neurons in substantia nigra cause

Answer 19

parkinson’s disease

Question 20

chorea

Answer 20

described as “dancing”
typically more proximal

Question 21

number of layers in the cerebellar cortex

Answer 21

3

Question 22

athetosis

Answer 22

described as “snake-like”
usually more distal

Question 23

layers of the cerebellar cortex

Answer 23

granule layer
Purkinje cell layer
molecular layer

Question 24

Granular layer

Answer 24

innermost layer containing tightly packed small granule cells that provide excitatory output to other cerebellar cells via parallel fibers

Question 25

Purkinje layer

Answer 25

the middle layer, containing the cell bodies of Purkinje cells which provide inhibitory input to the deep cerebellar nuclei

Question 26

Molecular layer

Answer 26

outermost later, contains the dendrites and axons of interneurons (Golgi, basket, and stellate cells)

Question 27

basket and stellate cells

Answer 27

receive excitatory input from granule cells via parallel fibers and inhibit Purkinje cells

Question 28

Golgi cells

Answer 28

receive excitatory inputs from granule cell parallel fibers and provide feedback inhibition to granule cells

Question 29

number of layers in cortical tissue

Answer 29

6

Question 30

only cells to inhibit deep cerebellar nuclei

Answer 30

Purkinje cells

Question 31

cerebellum macroscopic anatomy

Answer 31

2 lateral hemispheres and a midline vermis dorsal to the pons and medulla and separated from the occipital lobe via the tentorium

Question 32

folia

Answer 32

cerebellar hemispheres' marked infoldings

Question 33

atrophy of the folia seen in

Answer 33

patients with chronic alcohol use

Question 34

mass lesions, swelling, or elevated intracranial pressure causes

Answer 34

cerebellum can herniate through the foramen magnum and compress the brainstem

Question 35

cerebellar peduncles

Answer 35

connect cerebellum to other brain structures via 3 paired major white matter tracts

Question 36

superior cerebellar peduncle

Answer 36

mostly EFFERENT/output fibers that relay to the thalamus and spinal cord

Question 37

middle cerebellar peduncle

Answer 37

contains INPUT from various regions of the cerebral cortex

Question 38

inferior cerebellar peduncle

Answer 38

contains INPUT from the spinal cord and lower brainstem

Question 39

deep cerebellar nuclei

Answer 39

located in cerebellar white matter from lateral to medial: dentate, emboliform, globose, and fastigial nuclei main output centers of the cerebellum, efferent fibers exiting via superior cerebellar peduncle

Question 40

cerebellar nuclei mnemonic

Answer 40

"Don't Eat Greasy Food" Dentate, Emboliform, Globose, Fastigial

Question 41

dentate nucleus

Answer 41

largest dysfunction can lead to hiccups or palatal myoclonus as it is part of Mollaret's triangle

Question 42

Mollaret's triangle

Answer 42

ipsilateral red nucleus ipsilateral inferior olivary nucleus contralateral dentate nucleus

Question 43

emboliform and globose nuclei

Answer 43

sometimes called interposed nuclei help with initiating movements and keeping movements smooth

Question 44

fastigial nuclei

Answer 44

receive inputs from the vermis and help with walking and stability while standing

Question 45

cerebellar lesion symptoms

Answer 45

input/output fibers "double-cross" with a net result of having ipsilateral symtpoms

Question 46

climbing fibers

Answer 46

originate from the contralateral inferior olivary nucleus enter cerebellum via inferior and middle cerebellar peduncles provide excitatory input to the granule and Purkinje cells

Question 47

mossy fibers

Answer 47

originate from several locations throughout the cortex, vestibular nuclei, and spine enter cerebellum via inferior and middle cerebellar peduncles provide excitatory input to the granule and Purkinje cells

Question 48

vascular supply to the cerebellum

Answer 48

three main arteries: posterior inferior cerebellar artery (PICA), anterior inferior cerebellar artery (AICA), and the superior cerebellar artery (SCA)

Question 49

cerebellum vascular territories

Answer 49

Question 50

posterior inferior cerebellar artery (PICA)

Answer 50

arises from the vertebral artery largest vascular supply to the cerebellum

Question 51

PICA supplies

Answer 51

lateral medulla and most of the posterior and inferior portions of the cerebellum

Question 52

PICA strokes

Answer 52

high risk for cerebellar herniation due to large vascular territory most common cerebellar stroke

Question 53

PICA stroke presentation

Answer 53

vomiting, vertigo, horizontal ipsilateral nystagmus, and truncal ataxia if other PICA-supplied structures are affected, can present with lateral medullary syndrome

Question 54

head impulse test

Answer 54

can help differentiate posterior circulation stroke from peripheral vertigo. a normal head impuse testing in the setting of vertigo, nausea, and vomiting are more suggestive of brainstem insult. peripheral vertigo will have significant lag with corrective saccades with movement in one horizontal direction only

Question 55

head impulse test peripheral vertigo

Answer 55

significant lag with corrective saccades with movement in one horizontal direction only

Question 56

head impulse test brainstem insult

Answer 56

stroke from peripheral vertigo. a normal head impuse testing in the setting of vertigo, nausea, and vomiting

Question 57

anterior inferior cerebellar artery (AICA)

Answer 57

supplies the inferior lateral pons, the middle cerebellar peduncle, and a strip of the anterior cerebellum between the territories of the PICA and SCA

Question 58

AICA strokes

Answer 58

very rare vessel occlusion leads to sudden dysmetria and vertigo, and ipsilateral sensorineural hearing loss

Question 59

labyrinthine/internal acoustic artery

Answer 59

branch of the AICA, which supplies the inner ear occlusion contributes to hearing loss

Question 60

superior cerebellar artery (SCA)

Answer 60

supplies the upper lateral pons, superior cerebellar peduncle, and most of the superior half of the cerebellar hemisphere including the deep cerebellar nuclei

Question 61

SCA stroke

Answer 61

ataxia, nystagmus, and dysarthria