Thalamus Flashcards
(121 cards)
1
Q
What are the 4 parts of the thalamus?
A
- Epithalamus
- Subthalamus
- Hypothalamus
- Dorsal thalamus
2
Q
Which part of the thalamus is connected to the pineal gland?
A
Epithalamus
3
Q
What is the function of the pineal gland?
A
- Secretes melatonin
- Develop sex organs
- Limbic system
4
Q
What are the 3 portions of the epithalamus?
A
- Habenular trigone and nuclei
- Pineal body
- Striate medularis
5
Q
What structure does the epithalamus form the roof of?
A
The 3rd ventricle
6
Q
What is the subthalamus?
A
- Border between thalamus and midbrain just rostral to substantia nigra
7
Q
What part of the thalamus is referred to generally when people refer to the thalamus?
A
- Dorsal thalamus
8
Q
What systems does the epithalamus link?
A
- Link between limbic system in forebrain and other parts of the brain
9
Q
What substances is the habenula nucleus involved in releasing?
A
- Neuromodulators
- Dopamine
- Norepinephrine
- Serotonin
10
Q
What is the main function of the subthalamus
A
Regulating movements produced by skeletal muscles
11
Q
What other important structures related to movement is the subthalamus connected to?
A
- Basal ganglia
- Substantia nigra
12
Q
Where is the subthalamus located?
A
Between dorsal thalamus and hypothalamus
13
Q
What makes up a majority of the subthalamus? What other gray matter and tracts are involved?
A
Subthalamic nucleus Also: - Zona incerta - Subthalamic fasciculus - Lenticular fasciculus - Ansa lenticularis
14
Q
What is the major function of the hypothalamus?
A
Homeostatic control
15
Q
Through what 2 systems does the hypothalamus maintain homeostasis? What other system is it involved in?
A
- Autonomic nervous system
- Endocrine through pituitary
- Limbic system
16
Q
How long is the dorsal thalamus from anterior to posterior? How long is the thalamus from ventral to dorsal?
A
- 3cm AP
- 1.5 cm VD
17
Q
What are the 2 regions of the dorsal thalamus?
A
- Allothalamus
- Isothalamus
18
Q
Which part of the thalamus is older phylogenetically?
A
Allothalamus
19
Q
Which part of the thalamus is newer phylogenetically?
A
Isothalamus
20
Q
Which portion of the thalamus makes up its bulk?
A
Isothalamus
21
Q
What are the 3 structures making up the allothalamus?
A
- Afferents from amygdala
- Centre-median parafascicular complex
- Intralaminar region
22
Q
What are the 4 functions of the dorsal thalamus?
A
- Relay and integration of sensory information
- Focus attention and maintain conciousness
- Relay and integrates motor information
- Perception of low grade pain
23
Q
What is the only sensory information that does not synapse directly on the thalamus before the cortex?
A
Smell
24
Q
What are the 2 relay motor nuclei?
A
- Ventral anterior
- Ventral lateral
25
What are the 3 relay sensory nuclei?
- Ventral posterior
- Lateral geniculate
- Medial geniculate
26
What is the limbic relay nucleus?
Anterior
27
What are the main features of relay nuclei?
- Reciprocal connections with specific areas of cortex
| - Relay information from long ascending tracts or from basal ganglia, cerebellium/ other motor nuclei
28
What effect with an ablation of specific cortical areas have?
- Degeneration of the relay nucleus to that specific area.
29
What are the 4 thalamocortical radiations, and what lobes to they project to?
Central: Frontal and Parietal (mostly parietal)
Optic: Occipital
Auditory: Temporal
Anterior: Frontal
30
What tracts synapse on the ventral posterior lateral nucleus?
- Nucleus gracilis
- Nucleus cuneatus
- Dorsal horn of spinal cord/ spinothalamic tract
31
What tracts synapse on the ventral posterior medial nucleus?
- Trigeminal sensory nuclei
32
To what structure in the cortex do the ventral posterior nuclei project to?
Primary somatosensory cortex
33
What structures synapse on the lateral geniculate body of the thalamus?
- Ipsilateral temporal hemiretina
- Contralateral nasal hemiretina
In reticular formation:
- Raphe nuclei
- Locus coeruleus
- Other areas in pons & medulla
34
What structure does the lateral geniculate nucleus project to in the cortex?
Primary visual cortex
35
What structure synapses on the medial geniculate body?
Inferior colliculus
36
Where does the medial geniculate synapse in the higher centers?
Primary auditory cortex
37
What structures synapse on the ventral lateral nucleus?
- Ipsilateral globus palldius & substantia nigra
- Contralateral dentate nucleus
- Spinothalamic tract & vestibular nuclei
- Precentral motor cortical area
38
What is the target structure if the ventral lateral nucleus of the thalamus?
- Primary motor cortex
| - Supplementary motor area
39
What part of the ventral lateral nucleus does the globus pallidus synapse on?
Anterior part
40
What part of the ventral lateral nucleus does the cerebellar/ vestibular nuclei and the spinal cord synapse on?
Posterior part
41
What part of the ventral lateral nucleus does the substantia nigra nucleus synapse on?
Medial part
42
What structures synapse on the ventral anterior nucleus?
- Ipsilateral globus pallidus
- Substantia nigra
- Premotor cortex
- Frontal eye field
43
What structure does the ventral anterior nucleus project to?
- Premotor cortex
| - Supplementary motor cortex
44
What structures synapse on the anterior nuclear group of the thalamus?
- Mammillary body of hypothalamus via mammillothalamic tract
45
What structures in the cortex does the anterior nuclear group project to?
- Anterior limbic area
- Cingulate gyrus
- Parahippocampal gyrus
46
What system is the anterior nuclear group a part of?
- Limbic system
47
What does the anterior nuclear group help to control?
- Alertness
| - Emotion
48
What does the anterior nuclear group help acquire?
Memory
49
What information do the association nuclei help to process?
- Emotional
| - Memory
50
What do association nuclei help to integrate?
Different types of sensation
51
Do the association nuclei receive direct inputs from long ascending tracts?
- No
52
What is another name for multimodal nuclei?
Association nuclei
53
Where do the association nuclei project to in the cortical areas?
Association cortical areas
54
What are the 3 nuclei of the association nuclei?
- Dorsomedial
- Pulvinar
- Lateral posterior
55
What are the 2 portions of the dorsomedial nuclei?
- Parvo cellular
| - Magno cellular
56
What are the functions of the parvo cellular nucleus?
- Affective behavior
| - Memory and integration of somatic visceral activities
57
What symptoms will result from a lesion to the parvo cellular nuclei?
- Flat emotional state transient memory loss
| - Anterograde amnesia
58
What is the function of the magno cellular nuclei?
Relay nuclei for smell
59
What is the function of the pulvinar nuclei?
Vision
60
What is the function of the lateral posterior nuclei?
- Form complex links between subcortical visual areas with association cortical visual areas
61
What structures synapse on the lateral dorsal nucleus?
- Happocampal formation
- Pretectal area
- Superior colliculus
62
What structures does the lateral dorsal nucleus synapse on?
- Cingulate gyrus
| - Visual association cortex
63
What structures synapse on the lateral posterior nucleus?
Superior colliculus
64
What structures does the lateral posterior nucleus synapse on?
- Parietal lobe
- Temporal lobe
- Occipital association cortex
65
What structures synapse on the pulvinar nucleus?
- Pretectal area
- Superior colliculus
- Retinas
66
What areas does the pulvinar nucleus synapse on?
- Association area of paretotemporal cortex
| - Visual areas in occipital and posterior temporal lobe
67
What structures synapse on the medial nuclear group?
- Hypothalamus
- Amygdala
- Other thalamic nuclei
- Prefrontal cortex
68
What structures does the medial nuclear group synapse on?
- Prefrontal cortex
- Post parietal cortex
- Limbic structures
69
What is the function of the lateral dorsal nucleus?
- Memory
| - Interpretation of visual stimuli
70
What is the function of the lateral posterior nucleus?
Interpretation of visual and other stimuli
71
What is the function of the pulvinar nucleus?
- Visual
- Perception
- Cognition
- Memory
72
What is the function of the medial nuclear group?
Integration of:
- Emotion
- Thought
- Judgement
73
What are the 3 non-specific nuclei?
- Reticular
- Intralaminar
- Midline (nucleus Reuniens)
74
How are the cortical projections of the non-specific nuclei connected to the cortex?
- Diffuse, widespread indirect
75
From where do the non-specific nuclei receive input?
- Reticular formation
| - Other areas of neural axis
76
What do non-specific nuclei help to regulate?
- Conciousness
- Arousal
- Attention
77
What is the function of the intralaminar nuclei?
- Cortical activation
| - Sensorimotor integration
78
What structures synapse on the intralaminar nuclei?
- Brainstem RF
- STT
- Cerebellar nu
- Pallidum
79
What structures do the intralaminar nuclei synapse on?
- Frontal lobes
| - Parietal lobes
80
What is the function of the midline nuclei?
- Part of limbic system
- Memory
- Arousal
81
What structures synapse on the midline nuclei?
- Brainstem RF
- Hypothalamus
- STTT
- Midbrain
82
What structures do the midline nuclei synapse on?
- Hippocampal formation
- Amygdala
- Nucleus accumbens
- Cingulate gyrus
83
What is the function of the reticular nucleus?
- Inhibitory modulation of thalamocortical transmission
84
What structures synapse on the reticular nucleus?
- Collateral of thalamocortical
- Corticothalamic
- thalamostriatal
- Pallidothalamic fibers
85
What strucutre does the reticular nucleus synapse on?
The body of the thalamus
86
What is the major artery of the thalamus?
Thamogeniculate artery
87
What artery does the tuberothalamic artery branch off of?
- The posterior communicating
88
What artery does the posterior choroidal artery branch off of?
- Posterior cerebellar
89
What artery does the thalamogeniculate artery branch off of?
Basilar
90
What artery does the thalamoperforating artery branch off of?
Basilar
91
What artery supplies the posterior thalamus?
Thalamoperforating artery
92
What artery supplies anterior area of the thalamus and the geniculate bodies?
Thalamogeniculate
93
What artery supplies the medioanterior portion of the lower half of the thalamus?
Posterior choroidal artery
94
What artery supplies the anterior area of the thalamus?
Tuberothalamic artery
95
What % of thalamic infarcts are of the anterior area?
12 %
96
In what % of people is the tuberothalamic artery missing?
33 %
97
How is personality altered by a tuberothalamic artery?
- Withdrawn
- Disorientation in time and place
- Euphoria
- Lack of insight
- Apathy
98
What non-personality effects result from a tuberothalamic region?
Impairments of:
- Recent memory
- New learnings
- Disoriented
99
What % of infarcts occur in the paramedian area?
35 %
100
What nucleus is typically affected by a lesion to the paramedian area of the dorsal thalamus?
Dorsomedian nucleus
101
What impairments result from a lesion to the paramedian area?
- Neuropsychological distrubances in arousal and memory
- Confusion
- Agitation
- Aggression
- Apathy
- Speech problems (soft speech)
- Dysprosody (difficulty speaking)
102
What arteries are severed in an inferolateral dorsal thalamus lesion?
Thalamogeniculate arteries
103
What % of thalamic infarcts are in the inferolateral area?
45 %
104
What symptoms may result from an inferolateral area?
- Ataxia
- Contralateral somatosensory sensation impairment
- Intractable/ affective pain
105
What % of thalamic infarcts are in the posterior area?
8 %
106
What symptoms result from a lesion to the posterior dorsal thalamus?
- Hypoesthesia (decreased sensitivity to light/ other sensations)
- Spatial neglect
- Homonymous horizontal sectoranopsia (loss of vision in a portion of the visual field)
107
What is thalamic sydrome?
Blockage in thalamogeniculate artery
108
What typically precedes thalamic syndrome?
Numbness in the affected side
109
What is the numbness of thalamic syndrome replaced by?
Varying burning and tingling sensations
110
What can accompany the burning and tingling of thalamic syndrome?
Hypersensitivity; dysaesthesias or allodynia
111
What are less common symptoms of thalamic syndrome?
Severe ongoing pain with little or no stimuli/ motor problems
112
What fibers make up the anterior limb?
- Anterior thalamic radiation
| - Frontopontine and other corticofugal fibers
113
What fibers make up the posterior limb?
- Corticopontine and other corticofugal(corticothalamic) fibers
- Superior thalamic radiation (includes somatosensory radiation)
- Corticospinal tract
114
What radiation projects from the medial geniculate nucleus?
Auditory radiation (inferior thalamic peduncle)
115
What radiation projects from the lateral geniculate nucleus?
Optic radiation (posterior thalamic peduncle)
116
What 3 motor tracts make up the internal capsule?
- Corticospinals
- Corticobulbars
- Corticopontocerebellar
117
From what lobe does the internal capsule originate?
The frontal lobe
118
What 2 nuclei do the fibers forming the anterior limb of the internal capsule pass between?
- Caudate nucleus
| - Lentiform nucleus
119
What structures do the fibers making up the posterior limb of the internal capsule pass between?
- Thalamus
| - Lentiform nucleus
120
What limb does the medial geniculate pass through?
The posterior limb
121
What is the intersection of the anterior and posterior limb of the internal capsule near the interventicular foramen termed?
Genu of the internal capsule
