3.18.14 33 Diencephalon

Question 1

Name all of the structures of the diencephalon (5)

Answer 1

Thalamus
Subthalamus
Hypothalamus
Epithalamus
3rd Ventricle

Question 2

What two major structures compose the epithalamus?

Answer 2

Habenula

Epiphysis (Pineal gland)

Question 3

What are the afferents to the habenular nucleus? Efferents?

Answer 3

Afferent: stria medullaris thalami
Efferent: habenulointerpenduncular tract

Question 4

What structures send info through the stria medullari thalami? Where are they going?

Answer 4

From septal and preoptic areas

To habenular nucleus

Question 5

Where are efferents from the habenulointerpeduncular tract bound?

Answer 5

From habenular nucleus to interpeduncular nucleus… duh

Question 6

What is another name for the pineal gland?

Answer 6

Epiphysis

Question 7

What is the activity of the pineal gland relative to light and dark?

Answer 7

Dark = ON; secretes melatonin into blood
Light = OFF

Question 8

Describe the cascade affecting the pineal gland during the daytime.

Answer 8

Light hits retina –> pretectum –> hypothalamus –> intermediolateral cell column –> superior cervical ganglion –> pineal gland is shut off

Question 9

What are the effects of melatonin?

Answer 9

Antigonadotropic (hypogonadism)

Sleep/wake cycle (feel rested)

Question 10

What is the primary function of the habenular nucleus?

Answer 10

Reproductive function (sex)

Question 11

Voltage gated calcium channels in the thalamus are active during tonic or burst firing?

Answer 11

Burst firing

Question 12

Detailed info and focus are associated with tonic or burst firing in the thalamus?

Answer 12

Tonic firing

Question 13

Basic awareness of an event (without details) is associated with tonic or burst firing in the thalamus?

Answer 13

Burst firing

Question 14

What two structures serve as regulators of the thalamus?

Answer 14

Cortex and reticular formation

Question 15

What is an example of the specific input/output scheme of the thalamus?

Answer 15

DCML –> VPL –> primary somatosensory cortex (From specific tract to specific cortical region)

Question 16

What nucleus of the thalamus DOES NOT project to the cortex?

Answer 16

The reticular nucleus; solely intrathalamic relay

Question 17

Example of serial processing?

Answer 17

Light to retina –> lat. gen. body –> area 17 –> 18 –> 19

Processive, in sequence

Question 18

Example of parallel processing?

Answer 18

Light to retina distributes to various pathways:

• Lat. gen. body (features)
• Suprachiasmatic nucleus (RACIST)
• Superior colliculus (HOMOPHOBE)

Question 19

Name the external relay nuclei and associated cortical areas

Answer 19

1. VPM (face; 3,1,2)
2. VPL (body; 3,1,2)
3. Lat.G (visual; 17)
4. Med.G (auditory; 41,42)

Question 20

Name the internal relay nuclei and associated cortical areas

Answer 20

1. VA (4,6)
2. VL (4,6)
3. AN (limbic; cingulate gyrus)

Question 21

Name the association nuclei and associated cortical areas

Answer 21

1. Dorsomedial (prefrontal)
2. LD (parietal, cingulate gyrus)
3. LP (parietal)
4. Pulvinar (TOP = Temp,Occ,Par)

Question 22

Name the diffuse nuclei and associated cortical areas

Answer 22

1. CM (from RF/basal ganglia; 4,6)
2. Parafascicularis (from RF/basal ganglia; cingulate gyrus)
3. Midline (RF/spinothalamic/trigeminothalamic; diffuse)
4. Reticular (none; only to thalamus)

Question 23

Which thalamic nucleus functions as a relay of info from the limbic system to the cingulate gyrus?

Answer 23

Anterior nucleus

Question 24

Which thalamic nucleus functions as a relay to the prefrontal cortex (behavior)?

Answer 24

Dorsomedial nucleus

Question 25

Which thalamic nucleus functions as a diffuse relay of info from the reticular formation and basal ganglia to the motor cortices (4,6)?

Answer 25

Centromedial nucleus

Question 26

Which thalamic nucleus relays motor information from the basal ganglia to the motor cortices (non-diffusely)?

Answer 26

VA and VL

Question 27

Which thalamic nucleus relays information from the superior colliculus? To where?

Answer 27

Lateral geniculate nucleus
Visual cortex (17)

Question 28

Which thalamic nucleus relays information from the inferior colliculus? To where?

Answer 28

Medial geniculate nucleus
Auditory cortex (41,42)

Question 29

Which thalamic nucleus relays information from the face to the postcentral gyrus (3,1,2)?

Answer 29

VPM

Question 30

Which thalamic nucleus relays information from the body to the postcentral gyrus (3,1,2)?

Answer 30

VPL

Question 31

Which thalamic nucleus relays information to a broad association area spanning the temporal, occipital, and parietal lobes?

Answer 31

Pulvinar

Question 32

Which thalamic nucleus relays information exclusively to the parietal association areas?

Answer 32

LD and LP

Question 33

What is the blood supply to the thalamus?

Answer 33

PCA branches:

1. Thalamoperforating (medial)
2. Thalamogeniculate (lateral)

Question 34

What is the blood supply to the corpus striatum?

Answer 34

Lateral striate (MCA branch)

Question 35

What is the blood supply to the internal capsule?

Answer 35

Lateral striate (MCA)
Anterior choroidal (internal carotid)

Question 36

The anterior limb of the internal capsule carries relays from what thalamic nuclei?

Answer 36

Anterior
Medial dorsal (DM; prefrontal cortex)
Ventral anterior

Question 37

The genu of the internal capsule carries relays from what thalamic nucleus?

Answer 37

Ventral lateral

Question 38

The posterior limb of the internal capsule carries relays from what thalamic nuclei?

Answer 38

Ventral posterior (VPM, VPL)

Question 39

A lacunar stroke to the posterior thalamus results in what condition?

Answer 39

Thalamic syndrome:
Contralateral hemianesthesia/hemiparesis
Weeks later: dysaesthesia (pain)