36 Diencephalon - Organization and function of thalamus and hypothalamus

Question 1

List the parts of the diencephalon.

Answer 1

1. hypothalamus (front + inferior)
2. epithalamus (posterior)
3. subthalamus
4. thalamus (middle)

Question 2

What is the main role of thalamus?

Answer 2

As a relay center

Question 3

_____________ separates the thalamus and the hypothalamus.

Answer 3

Hypothalamic sulcus

Question 4

______________ is the posterior limit of the floor of the diencephalon.

Answer 4

Mamillary body

Question 5

What are the superior boundaries of the diencephalon?

Answer 5

Connective tissues and choroid plexus of Tela choroidea

Question 6

What are the 2 layers of white matter in the diencephalon?

Answer 6

1. Internal medullary lamina

2. External medullary lamina

Question 7

Internal medullary lamina separates?

Answer 7

The medial group of thalamic neurons from the lateral group

• also encloses the anterior thalamic nucleus

Question 8

In the internal medullary lamina, there are some neurons dispersing in the layer to form the ________________, which relays ________signals from the spinoreticulothalamic tract to almost whole area of the cerebral cortex.

Answer 8

Intralaminar nucleus;

emotional

Question 9

In the internal medullary lamina, there are some neurons dispersing in the layer to form the Intralaminar nucleus, which relays emotional signals from the _______________ to _______________.

Answer 9

spinoreticulothalamic tract;

almost whole area of the cerebral cortex

Question 10

Pain, temperature and proprioception are relayed to the _______________thalamic nucleus of the diencephalon.

Answer 10

Ventral posterior

Question 11

What is lateral to the external medullary lamina?

Answer 11

internal capsule and globus pallidus

Question 12

How can the thalamic nucleus be categorized into 3 types? Give examples of each type.

Answer 12

1. Specific relay nuclei
   - VA, VL, VP
2. Association nuclei
   - anterior nucleus, mediodorsal nucleus, pulvinar
3. Non-specific nuclei
   - intralaminar nuclei, thalamic reticular nucleus

Question 13

Afferent and efferent of Ventral anterior nucleus.

Answer 13

Afferent: globus pallidus
Efferent: prefrontal cortex

Question 14

Afferents and efferents of Ventral lateral nucleus. (2 pairs)

Answer 14

Afferent 1: globus pallidus
Efferent 1: supplementary motor area
Afferent 2: cerebellum
Efferent 2: motor cortex

Question 15

Afferents and efferent of Ventral posterior nucleus (VPL and VPM).

Answer 15

Afferents: medial, spinal and trigeminal lemnisci

Efferects: somatosensory cortex

Question 16

Afferent and efferent of lateral geniculate nucleus.

Answer 16

Afferent: Optic tract (superior colliculus of midbrain)
Efferent: Primary visual cortex (visual area of occipital cortex)

Question 17

Afferent and efferent of medial geniculate nucleus.

Answer 17

Afferent: Inferior branchium (inferior colliculus of midbrain)
Efferent: Primary auditory cortex (superior temporal lobe)

Question 18

Which thalamic nucleus receives signals from dorsal column tract and spinothalamic tract?

Answer 18

Ventral posterolateral nucleus

Question 19

Which thalamic nucleus receives signals from head and neck and trigeminal thalamic pathways?

Answer 19

Ventral posteromedial nucleus

Question 20

_____________ are reciprocally connected to the association areas of the cerebral cortex.

Answer 20

Association nuclei

Question 21

Afferent and efferent of anterior nucleus.

Answer 21

Afferent: mamillary body
via mammillothalamic tract
Efferent: cingulate cortex

Question 22

Function of anterior nucleus?

Answer 22

Memory, limbic system

Question 23

Afferent and efferent of Lateral dorsal nucleus/ Dorsolateral nucleus ?

Answer 23

Afferent: hippocampus
Efferent: cingulate cortex

Question 24

Function of lateral dorsal nucleus?

Answer 24

Memory

Question 25

Afferent and efferent of mediodorsal nucleus?

Answer 25

Afferent: olfactory cortex, amygdala in temporal lobe Efferent: prefrontal cortex (reciprocal)

Question 26

Function of mediodorsal nucleus

Answer 26

Mood, cognition, judgement (limbic)

Question 27

Afferent and efferent of lateral posterior nucleus and pulvinar?

Answer 27

Afferent: superior colliculus (midbrain) Efferent: Visual and parietal association cortices

Question 28

Functions of lateral posterior nucleus and pulvinar?

Answer 28

Extrageniculate visual pathway, blindsight (lesion at visual cortex > still know whether light is on)

Question 29

Which association nuclei are involved in the limbic system? A. anterior nucleus B. lateral dorsal nucleus C. mediodorsal nucleus D. pulvinar and lateral posterior nucleus

Answer 29

C

Question 30

Afferents and efferents of intralaminar nuclei?

Answer 30

Reticular formation, spinothalamic tracts, trigeminothalamic tracts >> cerebral cortex and corpus stiratum

Question 31

Functions of intralaminar nucelis?

Answer 31

Consciousness and arousal, emotional component of pain

Question 32

____________ cortex is important for the perception of the emotional part of the brain.

Answer 32

Anterior cingulate

Question 33

Thalamic reticular nucleus is a group of ____________ neurons that form thin layers on the lateral side of the thalamus.

Answer 33

GABAergic

Question 34

Briefly know about hypothalamic nuclei (low chance to be examined )

Answer 34

- Anterior (above the optic chiasm) : preoptic, supraoptic, suprachiasmatic - Middle (above the infundibulum) : paraventricular, dorsomedial, lateral ,ventromedial, arcuate - Posterior (above the tuber cinereum+ mammillary body): posterior, mammillary, tuberomammillary, dorsal

Question 35

Medial forebrain bundle carries _________ fibers from brainstem to the cerebral cortex. Why is it highly activated in drug addicts, alcoholics?

Answer 35

aminergic = dopaminergic, cholinergic * includes axons coming from the ventral tegmental areas in the midbrain that projects anteriorly to the nucleus accumbens in the frontal cortex, which uses dopamine as neurotransmitters.

Question 36

Medial forebrain bundle is medial/ lateral to the hypothalamic neurons.

Answer 36

lateral

Question 37

The ___________system involves in the regulation of anterior pituitary hormones secretion (adenohypophysis). It includes the ______________ tract that involves preoptic, ventromedial and arcuate nuclei.

Answer 37

parvocellular; | tuberoinfundibular

Question 38

he ___________system involves in the regulation of posterior pituitary hormones secretion (neurohypophysis). It includes the ______________ tract formed by paraventricular and supraoptic nuclei.

Answer 38

magnocellular; | hypothalamohypophyseal

Question 39

What is the parasympathetic response upon stimulating the hypothalamus on the urinary bladder?

Answer 39

contraction of bladder

Question 40

What is the sympathetic response upon stimulating the lateral part of hypothalamus?

Answer 40

Stress-like response: 1. diffuse sympathetic discharge 2. increase adrenal medullary secretion

Question 41

____________ are brain regions where the BBB is incomplete, with fenestrated capillaries.

Answer 41

Circumventricular organs

Question 42

Give example of a prominent circumventricular organ.

Answer 42

area of postrema: located in the 4th ventricle ; others: pineal body, subfornical organ, median eminence, neurohypophysis, vascular organ of lamina terminalis