Cerebellum and Basal Ganglia Flashcards
1
Q
what is the primary function of the cerebellum and basal ganglia
A
- indirect influence on motor commands from primary and secondary motor cortices
- adjusts activity in descending extrapyramidal tracts
2
Q
main functions of basal ganglia
A
automatic, intensity, quality of movement, desire or drive to move
3
Q
main functions of cerebellum
A
smooth, orderly, sequenced, coordinated movement (SOS + C)
4
Q
where is the cerebellum located
A
in posterior cranial fossa
5
Q
how does the cerebellum connect to the medulla, pons and midbrain
A
via cerebellar peduncles (inferior, middle, superior)
6
Q
what are the 3 layers of the cerebellum
A
- flocculonodular lobe
- anterior lobe
- posterior lobe
7
Q
what are the 3 layers of the cerebellar cortex
A
- molecular
- purkinje layer
- granular layer
8
Q
most superficial layer of cerebellar cortex, contains dendrites of neurons from deeper layers
A
molecular layer
9
Q
middle layer that contains cell bodies of purkinje fibers
A
purkinje layer
10
Q
deepest layer, compact granule cells (interneurons), excitatory to purkinje cells via glutamate
A
granular layer
11
Q
what cells are unique to the cerebellum and have extensive dendritic arborization with many dendritic spines
A
purkinje cells
12
Q
what structures do purkinje cells receive input from
A
mossy fibers, climbing fibers and cerebellar interneurons
13
Q
purkinje cells sole output from cerebellum occurs via synapses where
A
vestibular nuclei in brainstem or on deep cerebellar nuclei
14
Q
what are the 3 interneurons in the cerebellum that have an inhibitory effect on purkinje cells and mossy fibers
A
- basket cells
- stellate (granule) cells
- golgi cells
15
Q
what are the two types of afferent fibers that carry information into the cerebellum
A
mossy and climbing fibers
16
Q
originate from cell bodies in spinal cord, vestibular nuclei and cerebral cortex via pontine nuclei
A
mossy fibers
17
Q
originate from contralateral inferior olivary nuclei in brainstem
A
climbing fibers
18
Q
indirectly influence purkinje cells via synapse on granule cells; directly influence deep cerebellar nuclei
A
mossy fibers
19
Q
winds around dendrites of purkinje cells and synapse directly on purkinje fibers; also synapse on deep cerebellar nuclei
A
climbing fibers
20
Q
what excites mossy and climbing fibers
A
glutamate
21
Q
worm-like structures in the center of cerebellum that divides it into hemispheres
A
vermis
22
Q
what are the 3 structures that attach the cerebellum to the brainstem
A
superior peduncle, middle peduncle, inferior peduncle
23
Q
attaches to the midbrain and carries the primary output axons to the thalamus and brainstem
A
superior peduncle
24
Q
attaches to pons and carries info from cerebral cortex into cerebellum; input
A
middle peduncle
25
attaches to medulla and carries information from spinal cord and inferior olivary nucleus into cerebellum; also carries info out of cerebellum from Purkinje cells directly to vestibular and reticular nuclei in brainstem; input and output
inferior peduncle
26
is there more afferent input or efferent outputs to/from the cerebellum
more afferent inputs (40:1 ratio)
27
what are the ways these axons enter the cerebellum (input)
inferior and middle cerebellar peduncles
28
what are the main places that afferents are coming from to the cerebellum
- vestibular system via CN 8
- SC via dorsal and ventral spinocerebellar tracts
- cerebral cortex via pathways through pons (corticoponotcerebellar)
- cerebral cortex via pathways through inferior olivary nucleus (cerebro-olivarycerebellar)
- cerebral cortex cia pathway through reticular formation (cerebroreticulocerebellar)
29
arise from purkinje cells that integrate incoming information and project onto pairs of ______ to allow for efferent flow of information
deep cerebellar nuclei
30
what are the 4 main deep cerebellar nuclei
- dentate nucleus
- fastigial nucleus
- nucleus interpositus - globuse nucleus and emboliform nucleus
31
what are the other names for the anterior lobe of the cerebellum
- palocerebellum
- spinocerebellum
32
where does the anterior lobe receive sensory input from
- dorsal and ventral spinocerebellar tracts
- cuneocerebellar tract from brainstem
- trigeminocerebellar projection
- visual and auditory information via brainstem nuclei
33
where does the anterior cerebellar lobe send information from fastigial nucleus and nucleus interpositus to
- vestibular nuclei --> lateral vestibular tract
- thalamus --> motor cortex
- red nucleus --> ruborspinal tract
34
what influence does the anterior lobe of cerebellum have on motion
- compares input from periphery with motor plan from cerebral cortex (modified command)
- regulate of muscle tone (flexor tone)
- coordination of postural activities and gait
35
what are the other names for posterior lobe of cerebellum
- neocerebellum
- pontocerebellum
36
receives input from premotor, sensory and other cerebral cortices via pontine nuclei (corticopontocerebellar projection)
posterior lobe
37
the posterior lobe send information from _____ to motor and premotor cortices via denothalamic fibers from the ventrolateral thalamus; also sends some information to the ______ in the midbrain
- dentate nucleus
- red nucleus
38
what influence does the posterior lobe have on movement
- works with premotor to plan movements
- coordinates fine, distal voluntary movement
- ability to judge time intervals and produce accurate rhythm
39
other names for flocculonodular lobe
- archicerebellum
- vestibulocerebellum
40
receives information from vestibular nuclei in brainstem and directly from CN 8 about static and dynamic positions of the head in space; also receives information from retina
flocculonodular lobe
41
flocculonodular lobe sends information to ______ and to reticular formation in brainstem from purkinje cells and ________
- vestibular nuclei
- fastigial nucleus
42
influences and coordination of flocculonodular lobe
- coordinates and influences eye movement and vestibulo-occular reflex via MLF
- influences postural muscles via vestibulospinal tract to maintain upright posture and horizontal head position
43
nuclei associated with medial zone of cerebellum
fastigial nucleus
44
regulation of tone, posture, locomotion and equilibrium
medial zone of cerebellum
45
nuclei associated with intermediate zone of cerebellum
emoboliform and globuse
46
governs spatially organized skilled movements, posture and tone of the ipsilateral extremities
intermediate zone of cerebellum
47
nuclei associated with lateral zone of cerebellum
dentate nucleus
48
governs spatially organized movements and skilled movements of the limbs
lateral zone of cerebellum
49
what system supplies blood to the cerebellum
vertebrobasilar system (PICA, AICA, SC)
50
supplies vermis, inferior and posterior cerebellar hemispheres
posterior inferior cerebellar artery (PICA)
51
supplies a portion of the vermis and hemisphere anterior to PICA
anterior inferior cerebellar artery (AICA)
52
supplies superior half of vermis and hemispheres
superior inferior cerebellar artery (SC)
53
equilibrium and modulation of VOR is regulated by
vestibulocerebellum
54
gross movement of limbs is regulated by
spinocerebellum
55
fine, distal voluntary movement is regulated by
cerebrocerebellum
56
what is heavily involved in motor learning of voluntary movements
cerebellum
57
what are the 6 rules about cerebellar influence on movement
- all information entering cerebellum terminates in a specific lobe depending on the role in movement
- cerebellum receives lots of sensory input but is an indirect part of the motor system
- not directly connected to the motor pathways but inhibits or facilitates so that movements are smooth, orderly and sequenced
- coordinates and compares intended movement with actual movement and corrects movement errors
- coordinates movement to ensure upright posture and complex hand functions
- involved with learned patterns of movement and motor planning
58
practicing a new movement sends lots of information to the cerebellum via
spinocerebellar tracts
59
as a new task is learned, cerebellar activity
decreases
60
signs and symptoms of cerebellar lesions
- ataxia
- dysarthria
- nystagmus
- dysdiadochokinesia
- action or intention tremor
- dysmetria
- tibuation
61
cerebellar symptoms that occur with unilateral lesions produce signs and symptoms on which side
ipsilateral side
62
lack of coordination; jerky, inaccurate movement
ataxia
63
is ataxia due to hypertonia
no
64
_____ lesions to cerebellum produce truncal ataxia with loss of sitting or standing balance
mdiline
65
_____ lesions to cerebellum along side the vermis produces gait ataxia (staggering)
paravermal
66
______ cerebellar hemisphere lesions produce limb ataxia
lateral
67
how to test for ataxia
positive romberg test with EO and EC; vibration, proprioception and ankle reflexes remain normal
68
is a rhythmic tremor of head or trunk when sitting or standing, or with postural changes of the head where head is held rotated or tilted to one side
titubation
69
caused by dysfunction to spinocerebellum and often occurs due to chronic alcoholism that damages the anterior lobe of cerebellum
gait ataxia and titubation
70
slurred, poorly articulated speech
dysarthria
71
involuntary back and forth movement of the eyes
nystagmus
72
dysarthria and nystagmus occur due to damage of what
vestibulocerebellum
73
inability to rapidly alternate movement as in supinating and pronating forearm or alternate toe tapping
dysdiadochokinesia
74
inability to accurately move an intended distance (past-pointing)
dysmetria
75
shaking of the limb during voluntary movement
action or intension tremor
76
what are the 5 subcortical nuclei that make up the basal ganglia
caudate
putamen
globus pallidus
subthalamic nucleus
substantia nigra (pars compacta, pars reticulata)
77
part of substantia nigra and produce dopamine, gives substantia nigra its dark color
pars compacta
78
output part of substantia nigra
pars reticulata
79
neurological classifications of the basal ganglia
- striatum = caudata and putamen
- lentiform nucleus = putamen and globulus pallidus
80
the caudate, putamen and globus pallidus are located within the cerebrum and form what structure
corpus striatum
81
where are the caudate, putamen, and globus pallidus located
base of cerebrum
82
where is substantia nigra located
midbrain
83
where is subthalamic nucleus located
inferior to the thalamus and lateral to hypothalamus
84
where does the internal capsule run between
basal ganglia and thalamus
85
what are the 3 primary functions of the basal ganglia
- sequencing movement
- regulating muscle tone and force
- influencing mood and motivation for movement
86
the basal ganglia have both ____ and ____ influences on motor movement
inhibitory and excitatory
87
what are known as input nuclei in basal ganglia
caudate and putamen
88
what are known as the exit nuclei in basal ganglia
substantia nigra and globus pallidus
89
the basal ganglia has no direct connection with the spinal cord so it influences movement via ______ and _____ via multiple looping systems
motor areas of cerebral cortex and extrapyramidal pathways
90
what are the 4 loop systems that connect the basal ganglia to the thalamus and cerebral cortex
sensory motor loop
occulomotor loop
limbic loop
association loop
91
supplementary motor area projects onto basal ganglia providing input regarding sequencing actions of learned motor activities
sensory motor loop
92
frontal eye fields, prefrontal cortex and posterior parietal cortex relate information needed for voluntary saccadic movements of the eyes yes
occulomotor loop
93
eyes move together, eyes able to follow a target smoothly
smooth pursuit
94
eyes moving between 2 objects
saccidic movements
95
dopamine producing cells in subthalamic nucleus send axons to limbic centers associated with emotional and motivational aspects of movement (reward seeking behavior) and facial expressions/body language associated with movement
limbic loop
96
connections with association areas in all 4 lobes of the cortex that have to do with planning motor activity and determining the direction of movement
association loop
97
caudate and putamen receive afferent input from what
cerebral cortex, thalamus and sustantia nigra
98
caudate and putamen process information and sends it out on 1 of 2 pathways to where
globus pallidus internus and substantia nigra (efferent)
99
turns up the motor system by exciting the thalamus
direct pathway from globus pallidus internus and substantia nigra
100
turns down the motor system by inhibiting the motor thalamus
indirect pathway
101
what are the 3 neurotransmitters associated with basal ganglia
dopamine, GABA, glutamate
102
what is the direct pathway of excitation in basal ganglia
from putamen --> globus pallidus internus --> motor thalamus --> motor cortex
103
what neurotransmitter is used in the direct pathway to disinhibit the thalamus
GABA
104
results if movement is not modulated by the motor cortex
huntington's (chorea) disease
105
what is the flow of indirect pathway of basal ganglia
putamen --> globus pallidus externus --> subthalamic nucleus --> globulus pallidus internus ---> motor thalamus --> motor cortex
106
what neurotransmitter is utilized in indirect pathway as used by the subthalamic nuclei
glutamate
107
alters the balance of the direct and indirect pathway depending on activation of either D1 or D2 receptors in either of the pathways
dopamine
108
dopamine binding with __ receptors activates the direct pathway
D1
109
dopamine binding with ___receptors activates the indirect pathway
D2
110
basal ganglia has indirect influence on LMN's in spinal cord and brainstem via
extrapyramidal pathways
111
what is the blood supply to the basal ganglia
lenticulostriate arteries (penetrating branches off MCA)
112
slow, writhing movement
athetosis (dystonia)
113
brisk, involuntary movements of the distal limbs and face
chorea (dystonia)
114
most common basal ganglia motor disorder and is caused by death of dopamine producing cells in SN
parkinson's disease
115
inhibits motor thalamus too much
hypokinetic disorder --> PD
116
common sx of PD
rigidity, bradykinesia, resting tremor, postural and gait deficits, masklike facial expression, loss of automatic and voluntary movement
117
a hyperkinetic disorder and is the degeneration of striatum and cerebral cortex
huntington's chorea
118
results in disinhibition of thalamus in resulting in excessive activity of motor cortex
huntington's chorea
119
sx and outcomes of huntington's chorea
- chorea: involuntary, jerky, rapid movement
- dementia
- results in death
120
genetic, nonprogressive movement disorders; hyperkinetic; involuntary, sustained muscle contractions resulting in abnormal postures, twisting, repetitive movements
dystonia
121
affect one part of the body or one specific activity
focal dystonia
122
progressive, degenerative disease affecting basal ganglia, cerebellum, cerebral cortex and autonomic NS; pt will have slow movements and rigidity, postural hypotension, bowel and bladder incontinence, decreased sweating, tears and saliva, and decreased goal oriented behavior
multiple system atrophy/shy-drager syndrome
123
contralateral lesion of subthalamic nucleus; results in violent flinging movements; mostly affects proximal musculature on one side of the body
hemiballismus
