Neuro Ch. 15 up to KCCs, CSV Flashcards
(223 cards)
1
Q
What regions of the CNShave no direct connetion to lower motor neurons?
A
basal ganglia and cerebellum
2
Q
What is truncal ataxia?
A
unsteady gait
3
Q
What is appendicular ataxia?
A
ataxia of the limbs
4
Q
What is ataxia?
A
irregular, uncoordinated movement
5
Q
What side is ataxia in relation to a cerebellar lesion?
A
ipsilateral
6
Q
What are the deficits associated with midline lesions of the cerebellar vermis?
A
mainly truncal ataxia and eye movement abnormalities, often accompanied by intesnse vertigo, and N/V
7
Q
What are deficits associated with midline lesions fo flocculonodular lobes?
A
mainly truncal ataxia and eye movement abnormalities, often accompanied by intesnse vertigo, and N/V
8
Q
What are deficits associated with lesions lateral to the cerebllar vermis?
A
appendicular ataxia
9
Q
What are the functions of the cerebellum?
A
intergrates massive sensory and other inputs to coordinate movement and motor planning
articulation of speech
respiratory movements
motor learning
certain higher order cognitive processes possible
10
Q
What is the largest structure in the posterior fossa?
A
cerebellum
11
Q
To what does the cerebellum attach?
A
dorsal aspect of pons and rostral medulla, by three white matter peduncles
12
Q
What forms the roof of the fourth ventricle?
A
cerebellum
13
Q
What regions/structures does the cerebellum consist of?
A
vermis and two large cerebellar hemispheres
14
Q
What is the deepest fissure of the cerebellum?
A
primary fissure
15
Q
Where is the primary fissure?
A
dorsal surface of cerebellum; separating the anterior and posterior lobes
16
Q
Where is the posterolateral fissure?
A
ventral inferior surface of cerebellum; separating posterior lobe from the floculonodular lobe
17
Q
Where is the vermis?
A
midline (between the two cerebellar hemishperes?)
18
Q
The flocculonodular lobe has important connections to?
A
the vestubular nuclei
19
Q
What is the nodulus?
A
The most inferior portion of the cerebellar vermis; the midline structure to which the two flocculi are connected
20
Q
What connects the flocculi to the nodulus?
A
thin pedicles
21
Q
What is the most inferior portion of the cerebellar vermis
A
nodulus
22
Q
What can cause the tonsils to herniate?
A
mass lesions of the cerebrum or cerebellum, brain swelling with severely increased intracranial pressure
23
Q
Where can the cerebellar tonsils herniate?
A
through the forament magnum
24
Q
What is the result of tonsillar herniation through the foramen magnum?
A
compression of the medulla, which can result in death due to impingement on medullary respiratory centers
25
Where are the cerebellar tonsils?
inferior surface
26
What are the folia?
small ridges that run from medial to lateral on the surface of the cerebellum; (like gyri of cerebral cortex)
27
What forms the walls of the fourth ventricle?
cerebellar peduncles
28
What does the superior cerebellar peduncle mainly carry?
output fibers
29
What does the middle cerebellar peduncle carry?
mainly inputs
30
What does the inferior cerebllar peduncle carry?
mainly inputs
31
What cerebellar peduncles carry mainly outputs from the cerebellum?
superior peduncle
32
What cerebellar peduncles mainly carry inputs to the cerebellum?
middle and inferior peduncles
33
Alternative name of superior peduncle
brachium conjunctivum
34
Alternative name of the middle cereballar peduncle
brachium pontis
35
Alternative name of the inferior cerebellar peduncle
restiform body
36
How is the cerebellum divided?
into 3 functional regions based on input and output connections
37
What are the three functional regiosn of the cerebellum?
(medial) vermis and flocculonodlar lobes, intermediate hemispheres, lateral hemispheres (lateral)
38
What is the largest part of the cerebellum?
lateral hemispheres
39
What region of the cerebellum can have a large portion removed unilaterally without severe deficits?
lateral hemispheres
40
What is the function of the lateral hemispheres?
motor planning for extremities
41
What is the function of the intermediate hemispheres?
distal limb coordination (control of distal appendicular muscles in arms and legs)
42
What is the function of the vermis?
proximal limb and trunk coordination
43
What is the function of the flocculonodular lobe?
balance and vestibulo-ocular reflexes
44
What motor pathways are influenced by the cerebellar lateral hemispheres?
lateral corticospinal tract
45
What motor pathways are influenced by the cerebellar intermediate hemispheres?
lateral corticospinal trcat and rubrospinal tract
46
What motor pathways are influenced by the vermis?
anterior corticospinal tract, reticulospinal tract, vestibulospinal tract, and tectospinal tract
47
What motor pathways are influenced by the flocculonodular lobe?
medial longitudinal fasciculus (MLF)
48
What cerebellar regions influence the lateral corticospinal tract?
lateral and intermediate hemispheres
49
What cerebellar regions influence the rubrospinal tract?
intermediate hemispheres
50
What cerebellar regions influence the anterior corticospinal tract?
vermis
51
What cerebellar regions influence the reticulospinal tract?
vermis
52
What cerebellar regions influence the vestibulospinal tract?
vermis
53
What cerebellar regions influence the tectospinal tract?
vermis
54
What cerebllar regions influence the MLF?
flocculonodular lobe
55
Where does the superior cerebellar peduncle decussate?
caudal midbrain - at level of inferior colliculi
56
What nuclei are all cerebellar outputs relayed by?
Deep cerebellar and vestibular nuclei
57
What are the deep cerebellar nuclei from lateral to medial?
Dentate, Emboliform, Globose, Fastigial
58
What are the vestibular nuclei?
superior, medial and lateral
59
From what region does the dentate nuclei receive inputs?
lateral cerebellar hemispheres
60
From what region do the interposed nuclei receive inputs?
intermediate hemispheres
61
From what region does the fastigial nucleus receive inputs?
mostly vermis, small inputs from flocculonodular lobe
62
From what region do the vestibular nuclei receive inputs?
flocculonodular lobe
63
What is the largest deep cerebellar nuclei?
dentate nucleus
64
What nuclei is active just before voluntary movements?
dentate nucleus
65
What nuclei are active during and in relation to movements?
interposed nuclei
66
When is the dentate nucleus active?
just before voluntary movements
67
When are the interposed nuclei active?
during and in relation to movements
68
What are the interposed nuclei?
Emboliform and Globose
69
What are the layers of the cerebellar cortex? (superficial to deep)
molecular layer, purkinje cell layer, granule cell layer
70
What is contained within the molecular layer?
unmyelenated granule cell axons, purkinje cell dendrites, interneuons (basket cells, stellate cells), golgi cell dendrites
71
What cell type is extremely numerous?
granule cells - rival total of remainder of nervous system
72
What aer the two primary kinds of synaptic inputs in the cerebellum?
mossy fibers and climbing fibers
73
Where do mossy fibers arise from?
pontine nuclei and numerous regions
74
Where do mossy fibers synapse?
dendrites of granule cells
75
Where do granule cells synapse?
after bifurcating to form parallel fibers, synapse on numerous Purkinje cell dendrites, stellate cells, basket cells, and golgi cells
76
Are granule cells excitatory or inhibitory?
excitatory
77
What carries all outputs of the cerebellar cortex?
Purkinje cell axons into cerebellar white matter (to deep cerebellar and vestibular nuclei)
78
Where do Purkinje cells synapse?
deep cerebellar and vestibular nuclei
79
Are Purkinje cells excitatory or inhibitory?
inhibitory
80
Where do climbing fibers arise?
exclusively from neurons in the contralateral inferior olivary nucleus
81
Where do climbing fibers synapse?
they wrap around the cell body and proximal dendritic tree, forming powerful excitatory synapses on 10 Purkinje cells
82
What is the effect of climbinging fibers?
excitatory, having a strong modulatory effect on the response of Purkinje cells, causing a sustained decrease in their response to synaptic inputs from parallel fibers
83
How many climbing fibers is each Purkinje cell excited by?
only 1, although each climbing fiber synapses with about 10 Purkinje cells
84
Are climbing fibers excitatory or inhibitory?
excitatory
85
Where are basket cells located?
molecular layer
86
Where are stellate cells located?
molecular layer
87
Where do stellate cells terminate?
Purkinje cell dendrites in the molecular layer
88
What is the affect of stellate cells?
lateral inhibition of adjacent Purkinje cells (narrow the spatial extent of excitatory inputs to Purkinje cells - enhanced signal resolution in the spatial domain)
89
Are stellate cells excitatory or inhibitory?
inhibitory
90
Where do basket cells synapse?
Purkinje cell bodies
91
Are basket cells excitatory or inhibitory?
inhibitory
92
Where are golgi cells located?
granule cell layer
93
What is the function of Golgi cells?
provide feedback inhibition onto granule cells dendrites, which shortens the duration of excitatory inputs to the granule cells (enhanced signal resolution in the time domain)
94
What is the input to Golgi cells?
parallel fibers in the molecular layer
95
Are Golgi cells excitatory or inhibitory?
inhibitory
96
Where do Golgi cells synapse?
granule cell dendrites in the granule layer
97
What is the affect of basket cells?
lateral inhibition of adjacent Purkinje cells (narrow the spatial extent of excitatory inputs to Purkinje cells - enhanced signal resolution in the spatial domain)
98
What is the cerebellar glomuerulus
a region in the granule cell layer with complex synaptic interactions, containing axons and dendrites encapsulated in a glial sheath
99
Where are cerebellar glomeruli located?
granule cell layer
100
What is contained in cerebellar glomeruli?
large mossy fiber and Golgi cell axon terminals, which sysapse on granule cell dendrites
101
What encapsulates cerebellar goleruli?
glial sheath
102
How do cerebellar glomeruli appear?
small clearings among granule cells
103
What are the excitatory connections of the cerebellar cortex?
All the axons projecting upward: mossy fibers, climbing fibers, and granule cell parallel fibers
104
What are the inhibitory connection of the cerebellar cortex?
All axons projecting downward: Purkinje cells, stellate cells, basket cells, and Golgi cells
105
Are outputs of the deep cerebllar nuclei excitatory or inhibitory?
excitatory (they are not part of the cerebellar cortex)
106
What do lesions of the lateral cerebellum affect?
distal limb coordination
107
What do lesions of the medial cerebellum affect?
trunk control, posture, balance, and gait
108
What side do cerebellar lesions affecting coordination occur on?
ipsilateral
109
What are cerebellar lesions ipsilateral?
the pathways are double crossed
110
Where do cerebellar outputs first decussate?
in the decussation of the superior cerebellar peduncle in the midbrain
111
Where is the second crossing of cerebllar outputs?
corticospinal tract: pyramidal decussation
| rubrospinal tract: ventral tegmental decussation
112
What side does lesions of the vermis occur on?
bilateral?
113
What aren't lesions of the vermis typically unilateral?
the medial motor systems influence the proximal trunk muscles bilaterally
114
What are the fibers that enter the ventral lateral nucleus?
thalamic fasciculus
115
What are the more anterior parts of the thalamic fasciculus?
outputs from the basal ganglia
116
Where do cerebellar outputs terminate?
posterior VL (VLp; ventral lateral pars caudalis)
117
Where does the lateral cerebellar hemispehre project (first synapse)?
dentate nucleus
118
Where does the dentate nucleus project?
via the superior cerebellar peduncle to the contralateral VL and parvocellular red nucleus
119
Where does the superior cerebellar peduncle decussate?
midbrain
120
Where do fibers running throught the cerebellar peduncle project?
contralateral VL (after decussating in the midbrain)
121
Where does the VL project?
motor, premotor, supplementary motor cortex, and parietal lobe to influence motor planning in the corticospinal system
122
Where does the parvocellular division of the red nucleus project?
ipsilateral inferior olivary nucleus via central tegmental tract
123
Through what tract do fibers from the parvocellular red nucleus project?
central temental tract
124
What part of the red nucleus is th magnocellular division?
caudal division, gives rise to the rubrospinal tract
125
Where does the intermediate hemisphere project?
interposed nuclei (emboliform and globose)
126
Where do the interposed nuclei project?
via the superior cerebllar peduncle to the contralateral posterior VL, and magnocellular division of the red nucleus
127
What tract is influenced by the magnocellular division of the red nucleus?
rubrospinal tract?
128
What nuclei project to the parvocellular division of the red nucleu?
dentate nucleus (from lateral hemispheres)
129
What nuclei project to the magnocellular division of the red nucleus?
interposed nuclei (emboliform and globose) (from intermediate hemispheres)
130
Where does the vermis first project to?
fastigial nucleus
131
Where do fibers from the fastigial nuclei project?
uncinate fasciculus: contralateral vestibular nuclei
juxtarestiform body: ipsilateral vestibular nuclei and reticular formation
some through superior cerebellar peduncle: VL to motor cortex to anterior corticospinal tract; and also tectum
132
What carries the outputs from the fastigial nucleus?
mostly uncinate process and juxtarestiform body, small amount by sueprior cerebellar peduncle
133
Where does the uncinate fasciculus run?
loops over the superior cerebellar peduncle
134
Where do fibers from the uncinate fasciculus go?
after looping over sup cer ped, run caudally through the juxtarestiform body to the vestibular nuclei
135
Where does the juxtarestiform body run?
on the lateral wall of the fourth ventricle, must medial to the inferior cerebellar peduncle (restiform body)
136
What fibers are carried in the juxtarestiform body?
fibers in both directions between the vestibular nuclei and the cerebellum
137
Where do fibers from the juxtarestiform body project?
ipsilateral vestibular nuclei and reticular formation
138
What tract is influenced by the juxtarestiform fibers projecting into the vestibular nuclei?
vestibular spinal tract
139
What tract is influenced by the juxtarestiform fibers projecting into the reticular formation?
resticulospinal tract
140
What tract is influenced by the fastigial nucleus fibers that project to the VL?
VL to motor and association cortex to influence anterior corticospinal tract
141
What tract is influenced by the fastigial nucleus fibers that project to the tectum?
tectospinal tract
142
Where do fibers from the inferior vermis first synapse?
through juxtarestiform to ipsilateral vestibular nuclei
143
Where do fibers from the flocculonodular lobe first synapse?
through juxtarestiform to ipsilateral vestibular nuclei, small input to fastigial nucleus
144
What tract do vestibular nuclei outputs originating from flocculonodular lobe influence?
MLF and eye movement pathways
145
What tract do vestibular nuclei outputs originating from inferior vermis influence?
MFL and eye movement pathways
146
What is the vestibulocerebellum?
the flocculonodular lobes and inferior vermis - because they project mainly to the vestibular nuclei via juxtarestiform body
147
Connections between what regions are important for equilibrium and balance?
cerebellum and vestibular nuclei
148
What is the exception to the principle that cerebellum and basal ganglia do not project directly to LMNs?
some fastigial neurons project directly to the upper cervical spinal cord
149
What carries cerebellar inputs?
mossy fibers, exept those from the inferior olivary nucleus which is carried by climbing fibers
150
Where do collaterals from inputs to the cerebellar cortex synapse?
deep cerebellar nuclei
151
Where do inputs to the cerebellum arise from?
```
widespread areas:
cerebral cortex: virtually all
sensory modalities: vestibular, visual, auditory, and somatosensory
brainstem nuclei
spinal cord
```
152
Where do corticopontine fibers arise from?
cerebral cortex: frontal, temporal, parietal, and occipital lobes
153
What is the pathway for cerebellar inputs from the cortex?
pontocerebellar fibers (from corticopontine fibers)
154
What is the largest contribution of corticopontine fibers to the cerebellum?
primary sensory cortex, primary motor cortex, and some of visual cortex (travel through pontocerebellar fiber pathway)
155
Where do corticopontine fibers project?
through the internal capsule to pontine nuclei
156
Where are the pontine nuclei located?
in ventral pons interspersed with descending corticospinal and corticobulbar fibers
157
Where to pontocerebellar fibers project?
from pontine nuclei, cross midline to contralateral middle cerebellar peduncle
158
What are the spinocerebellar pathways?
dorsal spinocerebellar, cuneocerebellar, ventral spinocerebellar, and rostral spinocerebellar tracts
159
What is the function of the dorsal spinocerebellar tract?
provides rapid feedback to the cerebellum about ongoing limb movments so adjustments can be made - leg proprioceptors
160
What cerebellar input pathways provide information about limb movments?
dorsal spinocerebellar tract and cuneocerebellar tract
161
What is the difference between posterior column and spinocerebellar afferents?
spinocerebellar afferents don't reach conscious perception, posterior column fibers do
162
What is the origin of inputs to the dorsal spinocerebellar tract?
leg proprioceptors from dorsal root ganglia through gracile fascicle
163
Where do leg proprioceptors first enter the spinal cord?
dorsal root ganglia
164
Where do leg proprioceptors first travel after entering via dorsal root ganglia?
gracile fascile (posterior column)
165
Where do leg proprioceptors synapse before entering the dorsal spinocerebellar tract?
nucleus dorsalis of Clark
166
Where are the cells of the dorsal spinocerebellar tract located?
nucleus dorsalis of Clark
167
Where do cells of the dorsal spinocerebellar tract travel?
ascend in ipsilateral dorsal funiculus, giving rise to mossy fibers, travel through the inferior cerebellar peduncle to ipsilateral cerebellum
168
Where is the nucleus dorsalis of Clark located in the spinal cord?
a long column in dorsomedial spinal cord gray matter intermediate zone
169
What level is the nucleus dorsalis of Clark?
long column running through spinal cord from C8-L2/L3
170
What pathways project through the inferior cerbellar peduncle?
dorsal spinocerebellar tract, cuneocerebellar tract, and climbing fibers
171
What is the function of the cuneocerebellar tract?
provide rapid feedback to the cerebllum about ongoing movements, allowing fine adjustments to be made; arm proprioception
172
What sensory information travels in the cuneocerebellar tract?
arm and neck proprioception
173
What sensory information travels in the dorsal spinocerebellar tract?
leg proprioception
174
What is the main origin of the cuneocerebellar tract?
arm and neck proprioception throught the dorsal root ganglia, to the external cuneat nucleus
175
What does sensory information from arm proprioception first synapse on their way to the cerebellum?
external cuneate nucleus
176
Where is the external cuneate nucleus located?
in the medulla just lateral to the cuneat nucleus (aka accessory or lateral cuneate nucleus)
177
Where are the cells of the cuneocerebellar tract located?
external cuneate nucleus
178
Where does the cuneocerebellar tract travel?
inferior cerebellar peduncle to the ipsilateral cerebellum
179
Where do cells from the ventral spinocerebellar tract arise?
spinal border cells and intermediate zone neurons
180
Where are spinal border cells located?
outer edge of central gray matter of spinal cord
181
What is the function of the ventral spinocerebellar tract?
convey info about activity of spinal cord interneurons reflecting amount of activity in descending pathways; leg interneurons
182
What sensory information is conveyed by the ventral spinocerebellar tract?
leg interneuron feedback of descending pathway activity
183
What tracts convey information about activity of spinal cord interneurons reflexting amount of activity in descending pathways?
ventral and rostral spinocerebellar tracts (leg and arm/neck respectively)
184
Where do ventral spinocerebellar tracts decussate?
1. ventral commissure
| 2. superior cerebellar peduncle decussation (caudal pons?)
185
Where does the ventral spinocerebellar tract ascend?
contralaterally, ventral to dorsal spinocerebellar tract, and periopheral to anterolateral systems
186
What is the final destination fo the ventral spinocerebellar tract?
ipsilateral cerebellum
187
Through what cerebellar peduncle does the ventral spinocerebellar tract travel?
superior cerebellar peduncle
188
What is the function of the rostral spinocerebellar tract?
convey info about activity of spinal cord interneurons reflecting amount of activity in descending pathways; arm and neck interneurons
189
What sensory info is conveyed by the ventral spinocerebellar tract?
arm interneuron feedback of descending pathway activity
190
What cerebral peduncle does the rostral spinocerebellar tract travel through?
both inferior (ipsilateral) and superior (double crossed so contralateral?)
191
What spinocerebellar tracts travel through the superior cerebellar peduncle?
ventral and rostral spinocerebellar tracts
192
What spinocerebellar tract travels through both cerebellar peduncles?
rostral spinocerebellar tract
193
What is the main origin of the climbing fibers?
parvocellular red nucleus, cortex, brainstem, and spinal cord
194
Where are cell bodies of climbing fibers located?
inferior olivary nucleus
195
Where does the inferior olivary nucleus send its fibers?
olivocerebellar fibers cross to the medulla, travel through the inferior cerebellar peduncle, and terminate as climbing fibers in the contralateral cerebellum
196
What is the loop formed from the lateral cerebellum?
lateral cerebellum - dentate nucleus - cross through superior cerebellar peduncle - contralateral parvocellular red nucleus - inferior olivary nucleus - cross in medulla - inferior cerebellar peduncle - original cerebellar hemisphere
197
What connects the vestibular system and cerebellum?
vestibular inputs from Scarpa's vestibular ganglia dn vestibular nuclei (also MLF?)
198
What is the main origin of vestibular inputs?
vestibular system
199
Where are cells of vestibular inputs located?
primary vestibular sensory neurons: vestibular ganglia
| secondary vestibular sensory neurons: vestibular nuclei
200
Where do vestibular inputs travel?
through the juxtarestiform body to the ipsilateral inferior cerebellar vermis and flocculonodular lobes
201
What is an additional input to the flocculus?
visual inputs related to retinal slip, important for control of smooth pursuit of eye moevements
202
What is the function of noradrenergic inputs to the cerebellum?
neuromodulatory role
203
Where do noradrenergic inputs to the cerebellum originate?
locus ceruleus
204
Where do noradrenergic inputs project?
diffusely throughout the cerebellar cortex
205
What is the function of serotonergic inputs to the cerebellum?
neuromodulatory role
206
Where do serotonergic inputs to the cerebellum originate?
raphe nuclei
207
Where do serotonergic inputs project?
diffusely throughout the cerebellar cortex
208
What supplies the blood supply to the cerebellum, and where do they arise?
PICA (posterior inferior cerebellar artery) - usually from vertebral
AICA (anterior inferior cerebellar artery) - lower basilar
SCA (superior cerebellar artery) - top of basilar, just below PCA
209
What regions does the PICA supply?
lateral medulla, most of inferior half of cerebellum, and inferior vermis
210
What regions does the AICA supply?
inferior lateral pons, middle cerebellar peduncle, and a strip of ventral cerebellum b/w PICA and SCA territories - including flocculus
211
What regions does the SCA supply?
upper lateral pons, superior cerebellar peduncle, and most of superior half of cerebllar hemisphere - including deep cerebellar nuclei and superior vermis
212
What blood supplies the lateral medulla?
PICA
213
What blood supplies the inferior half of the cerebellum?
PICA
214
What blood supplies the inferior vermis?
PICA
215
What blood supplies the inferior lateral pons?
AICA
216
What blood supplies the middle cerebellar peduncle?
AICA
217
What blood supplies the strip of ventral cerebellum b/w PICA and SCA territories?
AICA
218
What blood supplies the flocculus?
AICA
219
What blood supplies the upper lateral pons
SCA
220
What blood supplies the superior cerebellar peduncle?
SCA
221
What blood supplies the superior half of the cerebellar hemisphere?
SCA
222
What blood supplies the deep cerebllar nuclei?
SCA
223
What blood supplies the superior vermis?
SCA
