Neuro3 Flashcards
1
Q
Where, in the brain, is the decision to move (somatic motor) made?
A
Heteromodal association cortices
prefrontal, parietotemporal, or limbic
2
Q
Where, in the brain, are the cortical motor planning regions?
A
Premotor cortex
Supplementary motor cortex
Frontal eye fields
Broca’s area
3
Q
What occurs after motor planning decision has been made?
A
Control circuits refine and assist with execution
4
Q
Where are the motor control circuits?
A
Primary motor cortex, cerebellum, and basal ganglia
5
Q
What are 7 primary descending motor pathways?
A
Corticospinal Corticobulbar Reticulospinal Rubrospinal Vestibulospinal Tectospinal
6
Q
The descending motor neurons are UPN/LMN?
A
UPN’s
7
Q
What to the descending pathway axons synapse with?
A
Interneurons (in the gray matter) and LMN’s in the Ventral Horns
8
Q
In most of the body, the LMN synapse is in the ______, but cranial nn. synapse in the ______.
A
Ventral horns of the spinal tract
In the nuclei of the brain.
9
Q
From what supra spinal structures do descending pathways originate?
A
Cortex and brainstem (neuronal cell bodies)
10
Q
T/F
Descending pathways usually synapse directly (monosynaptically) onto Alpha/Gamma MN’s in ventral horn of the spinal cord and cranial motor nuclei.
A
False.
Most (a majority) synapse with interneurons in the spinal cord.
11
Q
What other input do alpha and gamma MN’s receive?
A
segmental inputs from peripheral afferents
12
Q
Descending motor pathways can be both/and?
A
Excitatory
Inhibitory
(these pathways shut off certain mm.’s and activate others)
13
Q
What dictates the excitatory/inhibitory make-up of these descending motor pathways?
A
spatial and temporal summation with thousands of inhibitory/excitatory interneurons.
14
Q
The alpha/gamma motor neurons are considered to be…
A
LMN’s
15
Q
The descending pathways, along with the somas they arise from, are considered to be…
A
UPN’s
16
Q
What is the largest and clinically most important spinal tract?
A
The Corticospinal Tract
aka - pyramidal tract
17
Q
Where do the axons of the primary motor tract originate?
A
From somas mostly in the primary motor cortex
18
Q
Describe the pathway of the Corticospinal Tract from the brain to spinal cord.
A
Primary motor cortex > Corona Radiata > Internal Capsule > Cerebral peduncles > Pyramids
19
Q
What percentage of fibers from the Corticospinal tract decussate in the medullary pyramids?
A
85-90%
20
Q
Where do the crossed (85-90%) axons travel through the spinal cord?
A
Lateral Corticospinal Tract
lateral funiculus
21
Q
What percentage of corticospinal tract fibers have monosynaptic connections?
A
3-5%
22
Q
Where do the uncrossed (10-15%) fibers in the corticospinal tract descend?
A
Anterior Corticospinal tract
anterior funiculus
23
Q
What tract is regarded as the descending pathway most concerned with voluntary, discrete, skilled movements?
A
Lateral Corticospinal tract
the crossed one in the majority
24
Q
What tract controls bilateral axial musculature?
A
Anterior Corticospinal tract
25
What do Corticobulbar tracts innervate?
Cranial nn.'s
26
Describe the general pathway of a Corticobulbar tract.
Somas of motor cortex > corona radiata > internal capsule > cerebral peduncles > cranial nn.'s
27
Which CN's are innervated by Corticobulbar tracts?
```
III
IV
V
VI
VII
IX
X
XI
XII
```
28
Which CN's aren't innervated by Corticobulbar tracts?
I, II, VIII
29
What Corticobulbar tract is NOT crossed?
VII - facial nucleus
is bilateral
30
What are 2 functions of the Rubrospinal Tract?
Skilled dextrous movements of the upper extremity
Alternate route for achieving voluntary movement
31
Describe the pathway of the Rubrospinal Tract.
Cerebral Cortex and Cerebellum > Red nucleus > cross in Ventral Tegmentum as exit > Lateral funiculus
32
Where, specifically, does the Rubrospinal tract run in the spine?
Just anterior to the Lateral Corticospinal Tract
| in lateral funiculus
33
What are the 2 Reticulospinal Tracts?
Pontine
| Medullary
34
Where are the reticular spinal formation regions?
Pons and Medulla
35
What is the Medullary Reticulospinal tract also called, and what is its function?
aka Lateral Reticulospinal Tract
inhibits lower extremity extensors/facilitates flexors
36
What does the medullary reticulospinal tract do in terms of tone to the lower extremities?
Reduces muscle tone
37
T/F
| The medullary reticulospinal tract is crossed.
False
| It descends both crossed and uncrossed
38
The Pontine reticulospinal tract is also called..
aka Medial reticulospinal tract
39
Is the Pontine reticulospinal tract mostly crossed or uncrossed?
Mostly UNcrossed
| so they synapse ipsilaterally
40
What is the target of the Pontine reticulospinal tract?
Lower extremity extensors (alpha and gamma)
41
Does the Pontine reticulospinal tract increase or decrease tone?
Increases muscle tone
42
What are the 2 Vestibulospinal tracts?
LVST (lateral)
| MVST (medial)
43
The LVST and MVST can be thought of as pathways that counteract what force?
Gravity (they are postural)
44
What are 2 inputs to the Vestibular nuclei?
VIII and the cerebellum
45
What is the function of the Ascending nuclei of the vestibulospinal tract?
The vestibuloocular reflex
46
Where does the vestibuloocular reflex travel, and what does it coordinate?
Ascending portion of the MLF (medial longitudinal fasciculus)
Eye and head movements
47
From whence does the LVST arise?
Deiter's Nucleus
48
Does the LVST pathway descend crossed or uncrossed?
UNcrossed
49
What pathway in the spinal cord does the LVST use, and where does it terminate?
Anterior funiculus
All spinal levels
50
What mm.'s does the LVST facilitate?
LE extensors
| UE flexors
51
LVST is considered the primary....
Antigravity pathway
52
What is the primary function of the MVST?
Inhibit UE extensors
Facilitate UE flexors
(this is antigravity for the upper extremities)
53
Which spinal tract is involved in turning your head at something novel?
Tectospinal tract
54
Tectospinal tract pathway:
cell bodies in superior colliculus of midbrain > Tegmentum cross > travels with MVST to upper cervical spinal cord > turns head and neck
55
What do descending pathways terminate with?
interneurons and ventral horn motor neurons at different spinal levels.
56
What is the pathway of an LMN?
Ventral horn > ventral root > spinal root and peripheral nn.'s innervating m.
57
T/F
| mm.'s are innervated by a single spinal level.
False.
| Multiple levels go into many (larger) mm.'s
58
What happens if only 1 or 2 ventral roots are damaged?
Paresis (muscle weakening)
59
When does paralysis occur?
Either all ventral roots innervating a muscle are destroyed or UMN's damaged by a stroke.
60
What is the diaphragm innervated by?
C3-5
| meaning lesion above C3 leaves pt on ventilator
345 stay alive
61
T/F
| Most spinal cord lesions affect bowel and bladder.
True
| these are low (S2-4)
62
What motor neurons have large diameter, travel fast, and innervate extrafusal (motor unit) muscle?
Alpha MN
63
What motor neurons travel slow, have a small diameter, and innervate muscle spindle?
Gamma MN
64
Are Gamma MN's myelinated?
yes. but not as thick as alphas
65
What are the two types of autonomic fibers?
B-motor (pre-ganglionic) lightly myelinated
C-motor (post-ganglionic) unmyelinated
(told us to cross this question/table off)
66
What do Gamma MN's do to muscle, say, before a race?
Set tone. Gamma's fire a lot in response to anticipated exertion. Once exertion begins, Alpha MN's kick in.
67
What are the 5 separate nuclei that make up the basal ganglia?
```
Caudate
Putamen
Globus pallidus
Subthalamic nucleus
Substantia nigra (pars reticula and pars compacta)
```
68
What separates the caudate and the putamen?
The internal capsule
69
What are the two parts of the globus pallidus?
Externa and Interna
70
Is the nucleus Accumbens considered to be part of the basal ganglia?
Some think this is the 6th nuclei
71
Caudate + Putamen =
Striatum (or neostriatum)
72
Caudate + Putamen + Globus =
Corpus striatum
73
Putamen + Globus =
Lenticulate nucleus
74
What two parts of the brain are the basal ganglia highly connected to?
Cortex and the Thalamus
75
How many "channels" have been identified in the basal ganglia?
4
76
What are some symptoms of lesions to the basal ganglia?
Tremor
Rigidity
Difficulty initiating voluntary movements
Bradykinesia (slow movement)
Ballismus (jerky motions)
Choreoathetoid movements (inlvoluntary)
77
What are the 4 basal ganglia channels?
Occulomotor (eye movements)
Prefrontal (cognitive)
Limbic (emotional)
Motor
78
Do the basal ganglia have direct connections to the motor neurons in the spinal cord?
NO.
| stimulation of BG neurons does not directly cause movements (must be a relay area)
79
Do lesions of the Basal Ganglia cause paralysis?
NO
80
What function is the basal ganglia best know for?
Motor
81
What 4 specific functions does the motor channel have in the basal ganglia?
Formulation of general motor plans
Execution of specific motor plans
Scaling of motor intensity
Automatic execution of learned motor plans
82
What does dysfunction of the Formulation component of the Motor channel in basal ganglia cause?
Isolated motor acts only
83
What does dysfunction in the Scaling component of the Motor channel in basal ganglia cause?
Movement at inappropriate rates, amplitudes, and duration
84
What does a dysfunction in the Automatic execution component of the Motor channel in basal ganglia cause?
Much more mental effort must be applied to handwriting, tying shoes, etc.
85
What channel in the basal ganglia is implicated in motivation?
Limbic
| also emotion
86
Where do the outputs of the basal ganglia (specifically the corpus striatum) go?
Cortex
87
Where are the main inputs to the basal ganglia found?
| Where do these inputs originate?
Caudate and Putamen (striatum/neostriatum)
| Cortex and Thalamus
88
Are the inputs to the Striatum (caudate and putamen) excitatory or inhibitory?
Excitatory
| glutamatergic
89
Inputs to the Substantia Nigra pars compacta are...
Domaninergic
90
Where are the main outputs from the Basal Ganglia?
Globus Pallidus Interna
| Substantia Nigra pars Reticula
91
Are the main outputs from the Basal Ganglia excitatory or inhibitory?
Where do they go?
Inhibitory (GABAergic)
VL & VA of Thalamus, reticular formation, and superior colliculus
92
What other neurons in the Striatum (caudate and putamen) also play an important role in BG function?
Acetylcholinergic
93
What are the 2 main pathways of functional circuitry in the BG, and what modulates them?
Direct (excitatory) and Indirect (inhibitory)
Substantia Nigra circuit modulates.
94
What is the end result of Direct Pathway stimulation for the motor, prefrontal, and limbic channels?
Increased movement
Increased cognitive function
Increased emotions
95
Direct pathway of the BG:
Cortex (excitatory) > Caudate/Putamen (Inhibitory) > GPi/SNr turned off > Thalamus excitation from other stimuli > cortical stimulation
The Globus pallidus interna and Substantia Nigra can no longer inhibit the Thalamus, opening it to other stimuli
96
The Direct Pathway of the BG is excitatory/inhibitory?
Excitatory
97
The Indirect Pathway of the BG is excitatory/inhibitory?
Inhibitory
98
What is the end result of Indirect Pathway stimulation in the BG for the motor, prefrontal, and limbic channels?
Decreased movement, cognitive function, and emotions
99
Indirect pathway of the BG:
Cortex (excitatory) > Caudate/Putamen (inhibitory) > Globus Pallidus Externa
GPe can no longer inhibit the Subthalamic nuclei
Subthalamic nuclei (now excited by other input) > Globus Pallidus Interna/Substantia Nigra pars reticulata
GPi/SNr now excited for inhibitory action of Thalamus
Thalamus (now inhibited) > BLOCKS thalamic excitation of the cortex
100
SNc stands for:
Substantia Nigra pars compacta
101
What is the neurotransmitter for the SNc (nigrostriatal) pathway?
dopamine
102
Dopamine is _______ to the Direct pathway neurons in the Caudate/Putamen and ________ to the Indirect pathway of the Caudate/Putamen.
Excitatory
| Inhibitory
103
What is the downstream effect of the nigrostriatal (SNc) pathway firing ?
Excitation of the direct pathway
Inhibition of the indirect pathway
so, increased movement, emotions, and cognitive functions
104
Which pathway has D1 receptors?
Direct
105
Which pathway has D2 receptors?
Indirect
106
Do lesions of the basal ganglia cause paralysis?
NO
107
What is Bradykinesia
slow movements
cardinal sign of parkinson's
108
What is Athetosis?
| What is it associated with?
involuntary twisting movements
Huntington's disease, perinatal hypoxia, antipsychotic meds, anitemetic meds, Levadopa
109
What is Chorea?
| What is it associated with?
Involuntary fluid (dancelike) movements
Huntington's disease, perinatal hypoxia, antipsychotic meds, anitemetic meds, Levadopa, infarct/focal lesions of basal ganglia, lupus
110
What causes Ballismus?
usually unilateral lesion causing contralateral, involuntary, large flinging movements
111
T/F
| Tremors usually vary in frequency
False
| Tremors usually have specific frequency of movement
112
What is the difference between Rigidity and Dystonia?
Rigidity is resistance to passive movement of limb
| Dystonia refers to the assumption of distorted positions in limbs, trunk, or face.
113
What lesions of the BG cause Bradykinesia and Akinesia?
Substantia Nigra and Globus Pallidus Externa
114
If a lesion takes out the Putamen (specifically the Indirect pathway), what results?
Hyperkinesia
Chorea
Athetosis
115
What do lesions of the Caudate nucleus cause?
Few movement issues
| but, cognitive, emotional, and complex behaviors affected
116
What does a lesion in the Subthalamic nucleus cause?
Hemibalismus
117
What causes the abnormal movements of PD?
Removal of inhibitory influences on them
118
What are the 4 cardinal features of PD?
Tremor
Rigidity
Bradykinesia
Postural instability
119
T/F
| PD tremors mostly occur when at rest
True,
| although some pts have action tremor as well (this is tremor during movement rather than at rest)
120
What 2 types of rigidity are expressed in PD?
lead pipe and cog wheel
121
What is the most disabling feature of PD?
Bradykinesia
122
What are the 3 main pharmacological treatments for PD and how do they work?
Monoamine oxidase inhibitors (prevents breakdown of dopamine)
Dopamine agonist drugs (mimics dopamine)
L-DOPA (precursor to dopamine that crosses BBB)
123
Why would a DOPA decarboxylase inhibitor (drug called Sinemet) benefit recipients of L-DOPA?
It prevents L-DOPA conversion to dopamine in the plasma, increasing efficiency of delivery
124
What is the general term for movements indicating the failure of L-DOPA?
dyskinesias
| including head bobbing, lip smacking, tongue thrusting, etc
125
What are 2 surgical treatments for PD?
Deep Brain Stimulation
| Ablations (surgical lesions)
126
What type of charge does Deep Brain Stimulation deliver?
| What does it do?
Continuous
| reduces discharge of action potentials and rebalances control messages
127
Where is the electrode placed in DBS for disabling dyskinesias and tremor?
Globus Pallidus
128
Where is the electrode placed in DBS to reduce bradykinesia, tremor, and rigidity?
Subthalamic nucleus
129
Does successful DBS alleviate all the symptoms of PD?
No. Only some symptoms, and doesn't slow progression of disease.
130
What are the 2 ablations (surgical lesions) used to treat PD?
Thalamotomy (small area of thalamus to treat tremor)
| Pallidotomy (globus pallidus to treat akinesia)
131
What is a primary symptom of Huntington's disease?
Chorea - uncontrolled, rapid, dance-like
132
What causes the symptoms of Huntington's?
Loss of cholinergic and GABA-ergic neurons in the striatum (causes choreiform movements)
Loss of cortical cells thought to cause impaired cog. functions and dementia
133
What disorder is caused by vascular infarct, hemorrhage, or tumor of the subthalamic nuc.?
Ballism or Hemiballism
134
Does the cerebellum have any direct connections with spinal cord ventral horn motor neurons?
NO
135
What type of sensory input does the Cerebellum constantly receive?
body position, rate of movement, muscle length/force
136
What are 3 symptoms of cerebellar dysfunction?
Ataxia (loss of full control of body movements)
Hypotonia (low muscle tone)
Intention tremors (loss of muscle synergy)
137
Name 4 general functions of the cerebellum?
Compare actual/intended movements
Plan sequential movements
Learn coordinated movements
Produce synergy of movement
138
What separates the anterior and posterior lobes of the cerebellum?
Primary Fissure
139
What makes up the flocculonodular lobe?
2 flocculi
| 1 nodulus
140
What structure lies lateral to the nodulus and medial to the flocculi?
Cerebellar tonsils
141
Name 4 deep cerebellar nuclei and their targets:
Dentate (cerebrocerebellum)
Globose (spinocerebellum)
Emboliform (spinocerebellum)
Fastigial (vestibulocerebellum)
142
What is the main output pathway of the cerebellum?
Superior Cerebellar peduncle
143
What is the main input pathway of the cerebellum?
Middle cerebellar peduncle
144
What is the pathway of both input and output in the cerebellum?
Inferior peduncle
145
What are the two types of input fibers to the cerebellum?
Mossy fibers
| Climbing fibers
146
Where do cortico-ponto-cerebellar tract fibers enter the cerebellum?
middle cerebellar peduncle
147
Where do dorsal and anterior spinocerebellar tract fibers enter the cerebellum?
```
inferior peduncle (DCST)
superior cerebellar peduncle
```
148
What pathway is used by axons in the dorsal spinocerebellar tract to enter the cerebellum?
Inferior peduncle
149
Fibers going through the Pons to the cerebellum are termed _______ and fibers going through the Olivary are termed ______.
Mossy
| Climbing
150
How many spinocerebellar tracts are there?
4
151
What are the 4 spinocerebellar tracts and what peduncle receives their inputs?
Dorsal - Inferior peduncle
Ventral - Superior peduncle
Spinocuneocerebellar - cuneate nuclei/inferior peduncle
Rostral spinocerebellar - inferior AND superior peduncle
152
Where does the vestibular nerve enter the cerebellum?
Inferior peduncle
153
Climbing fibers entering the cerebellum via the inferior olivary nucleus receive inputs from where?
cortex, basal ganglia, red nucleus, extrapyramidal pathways
154
What peduncle is used by climbing fibers?
Inferior cerebellar peduncle
155
What is the function of the climbing fibers going through the olivary nucleus?
error correction and timing motor tasks
156
Lesions to the cerebellum cause ipsilateral/contralateral deficits?
Ipsilateral
157
What are the 3 cellular layers of the cerebellum?
Molecular
Purkinje
Granular
158
What 4 components make up the molecular layer of the cerebellar cortex?
Stellate cells
Basket cells
Parallel fibers
Dendrites of purkinje cells
159
What three components make up the Granular cell layer?
granule cells
Golgi cells
glomerulus
160
What are the 3 functional divisions of the cerebellum?
Vestibulocerebellum
Spinocerebellum
Cerebrocerebellum
161
Anatomically, what makes up the vestibulocerebellum?
Flocculonodular lobe
162
Vestibulocerebellum:
| Inputs/Outputs/Function
Inner ear/visual system via Inferior cerebellar peduncle
Fastigial nucleus > superior/inferior cerebellar peduncles > vestibular nuclei
Equilibrium, eye and head movements, posture
163
Spinocerebellum:
| Inputs/Outputs/Function
Spinal cord via superior/inferior peduncles
globose/emboliform nuclei > superior peduncle > reticular formation > contralateral thalamus > contralateral red nucleus
controls ongoing movements/innervates muscle spindles
164
What, anatomically, makes up the spinocerebellum?
Part of Vermis and part of cortices just lateral to Vermis
165
Where, anatomically, is the cerebrocerebellum?
Lateral cerebellar cortices
166
What is the input to the cerebrocerebellum?
cerebral cortex via middle peduncle
167
What is the output of the cerebrocerebellum?
Dentate nuc. > superior cerebellar peduncle > contralateral thalamus
168
What is the function of the cerebrocerebellum?
Formulation of motor plans and initiation of movements
169
What are three major signs of cerebellar dysfunction?
Hypotonia
Disequilibrium
Dyssynergia (there are 8 types listed)
170
What should you relate cerebellar damage to?
Being drunk
alcohol affects cerebellar.
Think roadside test for clinical considerations
171
What are 3 less common terms to classify sensory receptors?
Interoceptors (within body)
Proprioceptors (body position)
Exteroceptors (arise outside body)
172
Name 5 types of receptors:
```
Chemo
Photo
Thermo
Mechano
Noci
```
173
Receptors are, by definition...
Transducers
| translate energy and lie at border between outside and inside
174
T/F
| Some receptors are ends of a nerve, some use second messenger systems to stimulate a nerve.
True
175
What do receptor normally require in order to propagate an action potential?
Spatial and Temporal summation - graded - this fires the receptor potential
176
What are the two basic structural categories of cutaneous receptors?
Encapsulated
| non-Encapsulated
177
Do all receptors show adaptation to stimulus?
Yes.
| Although some rapid, some slow.
178
What class of nerve makes up free nerve endings?
```
Group III (A-delta) lightly myelinated
or Group IV (C) unmyelinated
```
179
What class of nerve makes up Hair receptors?
Group III (A-delta) lightly myelinated
180
What class of nerve are Merkel's tactile disks?
A-beta myelinated
| mechanoreceptor
181
Where do you find a high density of Meissner's corpuscles and what class of nerve innervates them?
Fingertips
| A-beta myelinated axons
182
What type of nerve is good at sensing vibration and is wrapped in layers of lamellae?
Pacinian
183
Pacinian corpuscles are innervated by what class of nerve?
A-beta myelinated
184
What class nerve makes up Ruffini endings?
A-beta myelinated
| senses maintained pressure (this is the deep one)
185
How is localization of a stimulus facilitated?
Lateral inhibition
186
What are 4 types of proprioceptors?
Joint
Muscle spindle
Golgi Tendon Organ
Cutaneous mechanoreceptors
187
What 4 types of endings make up joint receptors?
Free
Ruffini's
Pacinian corpuscles
Ligament receptors
188
Skeletal muscle fibers aka
| Muscle spindle fibers aka
Extrafusal
| Intrafusal
189
What are two terms used to describe intrafusal fibers depending on the arrangement of their nuclei?
Nuclear bag
| Nuclear chain
190
What nerve class innervates the nuclear chain fibers?
Group II afferent (flower spray)
191
What nerve class innervates the nuclear bag fibers?
Group 1a
192
The Group II is the ______ response and the Group 1a is the _______ response.
Static
| Dynamic
193
What is the MOTOR innervation for the muscle spindle fibers?
gamma MN's
They also set the sensitivity of the spindle
194
The GTO is sensitive to...
Muscle Force (not stretch)
it is 1b afferent
195
List the sensory nerve fiber classifications:
Ia (annulospiral ending from muscle spindle)
Ib (GTO)
II (flower spray on spindle)
A-beta (lower threshold cutaneous mechanoreceptors)
A-delta (aka group III) (nociceptors)
C (aka group IV) (nociceptors)
196
Important things about dermatomes:
C7 marks leading edge of arm
L4-5 marks leading edge of leg
complete anesthesia requires 3 consecutive dorsal roots cut
C1/coccygeal have no dermatomes (no roots)
197
What sensory modalities are carried by the Dorsal Column-Medial Lemniscal and the Trigeminal Lemniscal pathways?
```
Discriminative touch
2-point touch
vibration
kinesthesis
stereognosis
```
198
Where are the 1st, 2nd, and 3rd order neurons in the DCML?
1st - DRG A-betas run from peripheral to medulla
2nd - Medial Lemniscus (decussate as internal arcuate fibers, proceeds to thalamus)
3rd - VPL synapse, then thalamocortical projections proceed through corona radiata to cortex
199
Where does DCML fiber enter the spinal cord, and what are they called once they ascend?
Medial regions of Lissauer's tract
| Fasciculus gracilis and Fasciculus cuneatus
200
Where are the 1st, 2nd, and 3rd order neurons in the Trigeminal Lemniscal pathway?
1st - Trigeminal ganglion
2nd - Trigeminal sensory nucleus
3rd - VPM (thalamic)
201
Where is the decussation of the trigeminal lemniscal pathway?
Pons
202
Where do DCML fibers decussate?
Medulla
203
The DCML lower extremity neurons synapse...
nucleus gracilis
204
The DCML upper extremity neurons synapse...
nucleus cuneatus
205
Where are the 1st, 2nd, and 3rd order neurons in the Spinothalamic tract?
1st - DRG
2nd - Substantia gelatinosa of Rexed's lamina II
3rd - VPL (thalamus)
206
Where does the decussation of the Spinothalamic tract occur?
within two levels of entrance into the spinal tract.
at the Anterior White Commisure
207
Where are the 1st, 2nd, and 3rd order neurons in the Trigeminothalamic tract?
1st - Trigeminal ganglion
2nd - spinal nucleus in trigeminal n. in Medulla
3rd - VPM
208
Where does the decussation of the Trigeminothalamic tract occur?
Medulla
209
Both the spinothalamic and trigeminothalamic tracts carry what types of sensing fibers?
pain and thermal A-delta and C afferents
210
Some fibers of what pathway terminate in the brainstem reticular formation and are called the spinoreticular tract fibers?
Lateral Spinothalamic tract
211
The Lemniscal (DCML/trigeminal) and thalamic (lateral spinothalamic and trigeminothalamic) tracts are what type of pathways?
Conscious
212
The DSCT and the SCCT relay what type of information?
Proprioception from spindles and tendon organs to the Cerebellum
213
What are the 1st and 2nd order neurons in the Dorsal Spinocerebellar Tract?
1st - DRG
2nd - Clark's column in nucleus dorsalis
No Cross
214
What class of afferents are found in the DSCT?
Groups Ia and II (muscle spindle)
| Ib (tendon organ)
215
Where does the DSCT terminate, and what is its function?
Cerebellum via inferior cerebellar peduncle
| Fine coordination posture and limb (LE)
216
Where are the 1st and 2nd order neurons in the spinocuneocerebellar tract?
1st - DRG cervical
2nd - Cuneate nucleus
No decussation
217
What is the nerve class in the Spinocuneocerebellar tract, where do the fibers enter the medulla, and what is their function?
Group Ia and II (muscle spindle) and Ib (tendon organ)
Inf. peduncle
fine coordination of UE mm.
218
What type of info does the VSCT and the RSCT carry?
feedback to cerebellum about descending motor signals
219
Where does the VSCT decussate?
Anterior white commisure
then, after entering the superior peduncle, MOST cross again and end up IPSILATERAL
220
The RSCT (rostral spinocerebellar tract) carries what kind of info?
feedback to cerebellum about descending motor signals to cervical spinal cord.
221
How many synapses are involved in the stretch reflex?
one
stretches Ia and Group II afferents and loops back to the homonymous muscle
222
Does the stretch reflex involve the tendon organs?
NO
