Thalamus Flashcards

1
Q

Components of the diencephalon

A

Third ventricle, thalamus, sub thalamus, epithalamus, hypothalamus

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2
Q

Boundaries of diencephalon

A

posterior commissure dorsally to the interventricular foramina ventrally; dorsally bordered by roof of third ventricle, ventrally bordered by optic chasm, infundibulum, and mammillary bodies

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3
Q

What is the only sensory pathway that does not relay through the hypothalamus?

A

Olfaction

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4
Q

Reticular nucleus receives collaterals from…

A

both afferent and efferent thalamic axons and projects in turn to the other nuclei of the thalamus

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5
Q

What is the stratum zonale?

A

Rostral thin white matter layer covering the thalamus

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6
Q

Lateral white matter layer covering the thalamus

A

external medullary lamina

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7
Q

Y-shaped white matter that divides thalamus into 3 parts

A

internal medullary lamina

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8
Q

Components of the lateral part of the thalamus

A
  1. Dorsal tier
    - lateral dorsal nucleus
    - lateral posterior nucleus
    - pulvinar
  2. ventral tier
    - ventral anterior nucleus
    - ventral lateral nucleus
    - ventral posterior nucleus
    - medial and lateral geniculate bodies
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9
Q

reticular nucleus

A

located on the lateral surface of the thalamus between the external medullary lamina and the internal capsule

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10
Q

Input and output and function anterior nucleus of thalamus

A

input: hypothalamus (mammillary bodies and mammillothalamic tract)
output: to cingulate gyrus (anterior limb of IC)
function: emotional states and memory, alertness and attention

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11
Q

input, output and function of ventral anterior and lateral nuclei

A

input: basal ganglia and the cerebellum
output: motor and premotor cortices
function: provide the motor cortex with information received from the cerebellum and basal ganglia

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12
Q

subdivisions of ventral posterior nucleus

A
  1. ventroposterolateral nucleus -> somatosensory input related to body from medial leminscal and spinothalamic tract
  2. ventroposteromedial nucleus -> somatosensory input from the face from sensory nuclei of trigeminal nerve

-both project to primary somatosensory cortex

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13
Q

input, output centromedian nucleus

A

input: cerebral cortex, globus pallidus
output: projects to caudate and putamen

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14
Q

input, output and function of reticular nucleus

A

input: collateral branches of thalamocortical and corticothalamic fibers
output: thalamic nuclei
function: modulates influence that thalamus exerts on cortex

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15
Q

name the association thalamic nuclei

A

medial nucleus (dorsomedial nucleus), lateral dorsal nucleus, lateral posterior nucleus, pulvinar

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16
Q

what cortices do the association thalamic nuclei project to?

A

1 of 3: parietal-temporal-occipital association cortex, prefrontal association cortex, limbic association cortex

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17
Q

input, output and function of dorsomedial nucleus

A

input: olfactory cortex, amygdaloid nucleus and hypothalamus
output: prefrontal association cortex
function: affective behavior, mood influences

18
Q

name the condition that results from dorsomedial nucleus damage

A

Korsakoffs syndrome -> confabulation, memory loss

19
Q

input, output and function of lateral dorsal nucleus

A

input: hippocampal formation
output: cingulate gyrus
function: emotional behavior

20
Q

input, output of lateral posterior nucleus

A

input: unknown
output: somatosensory association cortex

21
Q

input, output and function of pulvinar

A

input: superior colliculus of midbrain, sensory association areas of parietal, temporal and occipital areas
output: parietal, temporal and occipital association cortices

22
Q

blood supply thalamus

A

mostly from the posterior cerebral artery, as well as the posterior communicating artery; additional from anterior and posterior choroidal arteries

23
Q

specific branches of the posterior cerebral artery that supply the thalamus

A

thalamopeforate artery and thalamogeniculate artery

24
Q

thalamoperforating arteries

A

origin: P1 segment
supply: medial thalamus (mediodorsal and intralaminar nuclei)

25
thalamogeniculate arteries
origin: P2 segment supply: lateral thalamus (VL, VPL, VPM, MGB, LGB), and pulvinar
26
what part of the thalamus does the medial posterior choroidal artery supply?
choroid plexus of 3rd ventricle, pineal gland, superior medial aspect of the thalamus
27
what part of the thalamus does the lateral posterior choroidal artery supply?
choroid plexus of the lateral ventricles and the lateral nuclear group of thalamus
28
what part of the thalamus does the anterior choroidal artery supply?
part of the LGB, ventrolateral nuclei and reticular nucleus
29
what part of the thalamus does the PCOM supply?
perforators to the inferior thalamus
30
Paramedian Artery of Percheron
single large P1 perforator that perfuses the medial aspect of thalamus (MD nucleus) bilaterally
31
What sensation characteristic will differentiate a lesion fo the thalamus vs somatosensory cortex?
vibration sense spared in somatosensory lesion; lost in thalamic lesions
32
ventral anterior nucleus inputs and outputs
input: medial segment of Globus pallidus and substantia pars reticulata output: frontal eye fields (area 8), premotor cortex, and SMA (area 6)
33
Thalamic radiations
4 distinct fiber peduncles that communicate the thalamus with the cerebral cortex
34
thalamic radiation projections
anterior-> frontal lobe inferior -> temporal lobe superior -> parietal lobe posterior -> occipital lobe
35
where do the thalamic radiations travel?
anterior -> anterior limb of IC superior -> posterior limb of IC inferior -> sublenticular region of IC posterior -> retrolenticular portion of IC
36
lesions of posterior limb of internal capsule can cause...
1. hemiparesis (corticospinal tract) 2. hemianesthesia (thalamocortical fibers) 3. hemianopsia (optic radiation) 4. hemihypacusis (auditory radiation)
37
neurotransmitters of thalamic projections
glutamate and aspartate
38
what thalamic nucleus is the only one to use inhibitory NT?
reticular nucleus (GABA)
39
components of the epithalamus
pineal body, stria medullaris thalami, habenular trigone and the roof (tela choroidea) of the 4th ventricle
40
Stria medullaris thalami
fibers originate in the septal nuclei, preoptic region of the hypothalamus and the anterior thalamic nuclei -> PROJECTS to habenular nuclei ->project to midbrain via fasciculus retroflexus
41
what does the pineal gland secrete
melatonin, serotonin, norepinephrine
42
the suprachiasmatic nucleus of the hypothalamus relays light cycle indirectly to the pineal gland through....
superior cervical ganglion