Diencephalon/subcortical, basal ganglia - subunit 1 Flashcards
week 6 - start of exam 2
1
Q
structures in the subocrtical region
A
- corpus callosum
- anterior commissure
- corona radiata
- internal capusle
- diencephaon
- pituitary gland
- pineal gland
- hippocampus
- amygdala
- basal ganglia
2
Q
axonal connections between teh left and right cerebral hemispheres, principally the fronta ldn parietal lobes
A
corpus callosum
3
Q
axonal connections between the left and right temporal lobes with projections to the amygdala
involved in the olfactory pathway
A
anterior commissure
4
Q
corona radiata and internal capsule
A
axonal connections between the cortex and thalamus to the brainstem and spinal cord
5
Q
strucutres and functions
internal capsule
includes:
A
- anterior limb
- genu
- posterior limb
6
Q
structure and function
diencephalon - thalamus
A
- composed of over 60 nuclei
- connnected with nearly all structures throughout the nervous sytem
- relays, integrates and sorts MOTOR and SENSORY info
- impacts COGNITIVE functions and mood/emotions
7
Q
structure and function
diencephalons - hypothalamus
A
- links nervous system to the endocrine system via pituitary gland
- assists with maintaining HOMEOSTASIS by controlling ANS and regulating hormones
8
Q
what 3 things does the hypothalamus play arole in
A
- detects thrist and hunger
- detects circadian rhythms
- regulates emotions
9
Q
structure and function
pituiatry gland (hypophysis)
A
- anterior and posterior portions
- secrete hormones that regualte gorwth, metabolism and reproduction
10
Q
structure and function
pineal gland
A
- assists melatonin secretion and circadian rhythm
- connects limbic system to other parts of brain
- regulates motor pathways
11
Q
structure and function
hippocampus
A
- technically part of temporal lobe
- long term memory storage
- connected to somatosensory cortex, thalamus, hypothalamus and brainstem
12
Q
structure and function
amygdala
A
- connections to primarliy cortex, thalamus, hypothalamus, hippocampus and brainstem
- encodes info about emotional events
- modulates cognitive functions such as memory, attention, perception
13
Q
strucutres and function
the limbic system
A
- interconnected group of many subcortical strucutes
- involved in emotional states, motivation, affect, attention, perception, learning and memory
- influences from endocrine system and ANS
14
Q
structure and function
basal ganglia
A
- striatum
- globus pallidus
- subthalamic nucleus (STN)
- substantia nigra (in midbrain)
15
Q
structure and function
basal ganglia - striatum
A
- caudate
- putamen
15
Q
structure and function
basal ganglia - globus pallidus
A
- internal segment (GPi)
- external segment (GPe)
16
Q
structure and function
basal ganglia- involved in feedback loops with cerebral cortex, thalamus and brainstem for motor movement
main functions:
A
- initiation, termination and control of movement
- eye movements (voluntary)
- behaviors, habits and procedurla learning
- cognition and mood
dopamine - has role in behaviors, habits, cognition and mood (intrinsic motivation)
17
Q
structure and function
basal ganglia - substantia nigra (in midbrain)
A
- pars compacta (SNpc)
- pars reticulata (SNpr)
18
Q
functions and pathways
basal ganglia - there are 3 intrinsic pathways that work together to produce coordinated voluntary movement
A
- direct
- indirect
- hyperdirect
19
Q
functiosn and pathways
in regards to the 3 intrinsic pathways of the basal ganglia
at rest, unwanted movement from cortex is INHIBITED by thalamus from there the basal ganglia can ?
A
basal ganglia can eitehr uplod this inibiton or couteract it (stimulate movement)
for example: when sitting the thalamus says stay calm! don’t move…when you then decide to move the basal ganglia will say either move or dont move
20
Q
basal ganglia functions & pathways
direct pathway = Go
talk about this pathway
A
inhibiotn of inhibitory neurons –> facilitates movement
1. cortex excites putamen via glutamate
2. putamen inhibits GPi via gaba
3. GPi is unable to inhibit thalamus
4. thalamus excites cortex via glutamate
5. this results in facilitation of movement
21
Q
basal ganglia functions & pathways
indirect pathway = no go
talk about this pathway
A
facilitation of inhibitory neuron –> inhibit movement
1. cortex excites putamen via glutamate
2. putamen inhibits GPe via GABA
3. GPe is unable to inhibit STN
4. STN excites GPi via glutamate
5. GPi inhibits thalamus via GABA
6. this results in inhibition of movement
22
Q
basal ganglia functions & pathways
hyperdirect pathway = stop
talk about this pathway
A
facilitation of inhibitory neurons –> inhibits movement
1. cortex ecites STN via glutamate
2. STN excites GPi via glutamate
3. GPi inhibits thalamus via GABA
4. this results in inhibition of movement
23
Q
How does dopamine help facilitate movement?
A
- substantia nigra pars compacta (SNpc) releases dopamine at the putamen
- the putamen has 2 dopamine receptors D1and D2
depending on which is stimulated, different pathways will be activated or inhibited - regardless of which receptor, the end result will be facilitation of movement
24
SNpc ---> ____________ --> D1 receptors --> facilitation of __________ pathway
- dopamine
- direct
25
SNpc --> ________ D2 receptors --> inhibition of _________ pathway
- dopamine
- indirect
26
at rest, what inhibits the thalamus to inhibit movement?
GPi
27
what pathway facilitates movement via inhibition of the GPi to have less inhibition on the thalamus
direct
## Footnote
the putamen is also involved in this pathway
28
what pathway inhhibits movemetn via activation of the STN and the GPi to have continued inhibition on the thalamus?
hyperdirect
29
dopamine facilitates movement by activating the _________ pathway via the ______ receptor and inhibiting the _____________ pathway via ________ receptors
- direct, D1
- indirect, D2
30
What is the primary function of the corpus callosum?
Axonal connections between L and R cerebral hemispheres – Frontal and Parietal lobes
31
What does the anterior commissure connect?
Axonal connection between the L and R temporal lobes with projection to amygdala
32
What is the role of the corona radiata?
Axonal connections between cortex and thalamus to the brainstem & spinal cord
33
What is the internal capsule's function?
Same as corona radiata
34
What is the main hub of the thalamus?
A large hub that connects nearly all structures throughout the nervous system
35
What functions does the hypothalamus assist with?
Maintaining homeostasis by controlling ANS and regulating hormones
36
What hormones does the pituitary gland secrete?
Hormones that regulate growth, metabolism, and reproduction
37
What is the function of the pineal gland?
Regulates circadian rhythm by secreting melatonin
38
What role does the hippocampus play?
Assists with long-term memory storage
39
What is the amygdala's primary function?
Encodes info about emotional events and modulates cognitive functions
40
What is the limbic system involved in?
Emotional states, motivation, affect, attention, perception, arousal, consciousness, learning, memory
41
What comprises the basal ganglia?
Striatum, globus pallidus, subthalamic nucleus, substantia nigra
42
What are the three intrinsic pathways of the basal ganglia?
* Direct pathway
* Indirect pathway
* Hyper direct pathway
43
What is the function of the direct pathway in the basal ganglia?
Facilitates movement
44
What does the indirect pathway in the basal ganglia do?
Inhibits movement
45
What is the role of dopamine in the basal ganglia?
Facilitates movement by activating the direct pathway and inhibiting the indirect pathway
46
What arteries supply the thalamus?
* Posterior cerebral artery (PCA)
* Anterior choroidal artery
47
What are common causes of lesions in subcortical areas?
* Stroke
* Infection
* Tumor
* Trauma
* Congenital anomalies
* Toxins
* Drugs
* Seizures
* Idiopathic
48
What is bradykinesia?
Smaller amplitude and/or slower movement
49
What characterizes rigidity?
Increased muscle tone that occurs in both directions at a joint
50
Define dystonia.
Involuntary sustained muscle contractions leading to abnormal postures
51
What is the function of the reticular formation?
Regulates sleep, breathing control, mood, memory, and maintains arousal and consciousness
52
Which cranial nerve is associated with smell?
CN I – olfactory
53
What is the role of CN II?
Vision, pupillary light reflex
54
What is the primary function of CN III?
Motor to 4 extraocular muscles
55
What are common signs of hypokinetic movements?
* Bradykinesia
* Rigidity
* Freezing
56
What is the clinical test for saccades?
Place your finger to the side of your head and cue the patient to look at your nose and alternate
57
What does the pyramidal decussation refer to?
Area where axons of corticospinal pathways cross
58
What is the role of the substantia nigra?
Part of basal ganglia pathways
59
What are the two types of tremors associated with basal ganglia damage?
* Resting tremor
* Intention/action tremor
60
What is the effect of lesions to the striatum?
Can lead to hyperkinetic movements like dystonia, athetosis, chorea, and ballismus
61
Fill in the blank: The _______ connects the limbic system to other parts of the brain.
Pineal gland
62
What is the primary function of CN I?
Smell (olfaction)
## Footnote
CN I is associated with the olfactory bulb in the frontal lobe.
63
Which cranial nerve is responsible for vision?
CN II - Optic
## Footnote
It is located in the thalamus.
64
What muscles does CN III innervate?
4 extraocular motor muscles and levator palpebrae superioris muscle
## Footnote
CN III originates from the midbrain.
65
What is the function of CN IV?
Eye movement
## Footnote
CN IV is the trochlear nerve originating from the midbrain.
66
Which cranial nerve has sensory and motor functions and is divided into three branches?
CN V - Trigeminal
## Footnote
The branches are V1, V2, and V3.
67
What is the primary function of CN VI?
Motor - abduction of the eye
## Footnote
CN VI is the abducens nerve located in the pons.
68
What functions are associated with CN VII?
Facial expression, taste, sensation near external auditory meatus
## Footnote
CN VII originates from the pons.
69
Which cranial nerve is responsible for balance and hearing?
CN VIII - Vestibulocochlear
## Footnote
It has vestibular and cochlear functions.
70
What are the functions of CN IX?
Taste part of tongue, sensation - middle ear, elevate pharynx and larynx
## Footnote
CN IX is the glossopharyngeal nerve located in the medulla.
71
What is the primary function of CN X?
Swallowing, gag reflex, voice
## Footnote
CN X is the vagus nerve, also located in the medulla.
72
Which cranial nerve innervates the sternocleidomastoid and trapezius muscles?
CN XI - Accessory
## Footnote
It branches from the spinal cord.
73
What is the primary function of CN XII?
Tongue muscles (protrude & deviate tongue to opposite side)
## Footnote
CN XII is the hypoglossal nerve located in the medulla.
74
Which cranial nerves are not considered true cranial nerves?
CN I & II
## Footnote
They are projections of the CNS.
75
Where do CN III and IV branch from?
Midbrain
## Footnote
CN III is the oculomotor nerve and CN IV is the trochlear nerve.
76
What is the vascular supply for cranial nerves and the brainstem?
Posterior circulation, anterior spinal artery, vertebral artery, PICA, AICA, basilar artery, paramedian branches of pons, circumferential branches of pons, SCA, PCA
## Footnote
These supplies are crucial for the function of cranial nerves.
77
What are some examples of etiology for brainstem lesions?
Stroke, seizure, infection, inflammation, drugs, genetic factors, tumor trauma, psychogenic causes, unknown
## Footnote
These can lead to various clinical conditions.
78
What is Wallenberg syndrome?
PICA stroke/lateral medullary syndrome
## Footnote
It results from damage to the posterolateral medulla.
79
Which cranial nerves are involved in dysphagia?
CN IX and CN X
## Footnote
They are associated with swallowing functions.
80
What is nystagmus?
Involuntary, abnormal eye movement, rapid and repetitive
## Footnote
It may indicate vestibular dysfunction.
81
What clinical sign is associated with coma?
Impaired consciousness and arousal
## Footnote
It results from damage to specific brain regions.
82
What is locked-in syndrome?
Loss of all voluntary motor functions except ocular movement
## Footnote
It occurs due to damage to the ventral pons.
83
What are common signs of cranial nerve palsies or lesions?
Monocular vision loss, abnormal pupillary light reflex, trigeminal neuralgia, abducens palsy, facial palsy, vestibular hypofunction, bulbar palsy
## Footnote
These signs vary depending on the affected cranial nerve.
84
How can cranial nerve function be assessed clinically?
Cognition tests, motor tests, sensory tests, cranial nerve tests, coordination tests, coma scales
## Footnote
Specific tests depend on the lesion's location.
85
# movement disorders
imbalance in the intrinsic pathways usually due to damage of the basal ganglia and/or dopaminergic neurons
- parkinsons disease
- huntingtons disease
- corticobasal degeneration
- multiple systems atrophy
- stroke of basal ganglia
86
# movement disorders
what is the common cause of hypokinetic movement (slow/small movement)
lesion to: dopaminergic neurons in SNpc
87
hypokinetic movements
direct pathway: over or underactive?
indirect/hyperdirect pathways: over or underactive
Direct pathway: underactive
indirect/hyperdirect pathways: overactive
88
# movement disorders
what is a common causes (s) of hyperkinetic movements (fast/large) ?
lesion to: striatum, STN and/or GPi
89
hyperkinetic movements:
direct pathway: over/under active?
indirect pathway: over/under active?
direct pathway: overactive
indirect pathway: under active
90
# movement disorders
bradykinesia/hypokinesia
rigidity
freezing
are all clinical signs of what type of movement?
hypokinetic
91
What is freezing?
severely impaired initation of movement and/or freezing during movement
92
# movement disorders
dystonia
athetosis
chorea
ballismus
tics
myoclonus
tremor
are all clinical signs of what type of movement?
hyperkinetic
## Footnote
indirect/hyper direct pathways are not working
93
resting tremor is associated with damage to?
basal gangial (
## Footnote
resting tremor is involuntary at rest
94
intention/action tremor is associated with damage to?
cerebellar damage
95
what is saccades
volunary control of eye movements
96
an abnormal test for saccades indicates what damage?
basal ganglia damage
- inability for eyes to volunatrily and accurately move to target in any direction
- may appear as inabiliity to initae movement or smaller eye movements than expected
