09b: Thalamus

Question 1

Ventricular structure separating R/L thalamus.

Answer 1

Third ventricle

Question 2

(X) is the major part of the diencephalon. Which groups of structures lie near (X) and are also part of diencephalon?

Answer 2

X = thalamus

1. Epithalamus (dorsal/caudal)
2. Subthalamus (ventral)
3. Hypothalamus (below)

Question 3

Major structures of epithalamus.

Answer 3

1. Pineal gland
2. Posterior commissure
3. Habenular nuclei

Question 4

(X) is a midsaggital endocrine gland in diencephalon that secretes (Y).

Answer 4

X = pineal;
Y = melatonin

Question 5

Melatonin secreted at high levels during (day/night) and is triggered by (X) signals.

Answer 5

Night

X = visual

Question 6

(X) is a fiber tract, part of epithalamus, that connects (Y) with their contralateral homologues.

Answer 6

X = posterior commissure;
Y = oculomotor nuclei and pretectal nuclei

Question 7

Formal name of the “thalamus” is:

Answer 7

Dorsal thalamus

Question 8

The (X) is a fiber layer that divides thalamus into which main parts/compartments?

Answer 8

X = internal medullary lamina;

1. Anterior
2. Medial
3. Lateral

Question 9

Anterior compartment of thalamus contains:

Answer 9

Anterior nucleus

Question 10

Medial compartment of thalamus contains:

Answer 10

Mediodorsal nucleus

Question 11

The (X) compartment of thalamus is divided into which tiers?

Answer 11

X = lateral

1. Dorsal
2. Ventral
3. Appended

Question 12

Dorsal tier of (X) thalamic compartment contains (Y).

Answer 12

X = lateral;
Y = pulvinar nucleus

Question 13

T/F: Pulvinar, aka “pillow”, nucleus of thalamus stains poorly with myelin.

Answer 13

True

Question 14

Ventral tier of (X) thalamic compartment contains (Y).

Answer 14

X = lateral
Y = VPL, VPM, VA, VL nuclei

Question 15

(Rostrally/caudally) in thalamus, the VPL/VPM complex is replaced by VA/VL complex.

Answer 15

Rostrally

Question 16

What are the Appended nuclei of the (X)?

Answer 16

X = thalamus (lateral compartment)

MGN and LGN

Question 17

(MGN/LGN) is more caudal than (MGN/LGN) and can be observed laterally to (superior/inferior) colliculus.

Answer 17

MGN; LGN;

Superior

Question 18

List categories of thalamic nuclei, based on functional organization.

Answer 18

1. Primary sensory nuclei
2. Motor relay nuclei
3. Association nuclei
4. Limbic nuclei

Question 19

List the primary sensory nuclei of the thalamus. List respective modality carried by each.

Answer 19

1. LGN (Vision)
2. MGN (Audition)
3. VPL (Somatosensory for body)
4. VPM (Somatosensory for face)

Question 20

List the motor relay nuclei of the thalamus. They carry info from (X) to (Y).

Answer 20

VA/VL Complex;

X = cerebellum and basal ganglia
Y = primary motor and premotor cortices

Question 21

Cerebellar input to (X) nuclei in thalamus comes from which specific part of cerebellum?

Answer 21

X = VA/VL

Dentate nucleus

Question 22

Basal ganglia, specifically (X), is source of input to (Y) nuclei in thalamus.

Answer 22

X = GP and SNpr (pars reticularis)
Y = VA/VL

Question 23

Association nuclei of thalamus receive (low/high) processed signals from (X), and project to (Y).

Answer 23

High;
X = association regions of cerebral cortex
Y = (back to) cerebral cortex

Question 24

List the association nuclei of the thalamus.

Answer 24

1. Pulvinar

2. Mediodorsal (MD)

Question 25

List the limbic nuclei of the thalamus.

Answer 25

Anterior nucleus

Question 26

Anterior nucleus receives some input from (X) via fornix and sends output to (Y).

Answer 26

``` X = hippocampus Y = cingulate cortex ```

Question 27

The "non-specific" nuclei of the thalamus are likely part of (X) system.

Answer 27

X = reticular activating

Question 28

T/F: All sensory signals travel through thalamus before reaching cerebral cortex.

Answer 28

False - all except olfaction

Question 29

The majority of neurons in thalamus are (short/long)-range, (excitatory/inhibitory) (X) neurons. The remainder are (Y) neurons.

Answer 29

Long; excitatory; X = relay Y = local, inhibitory (GABAergic) interneurons

Question 30

Most output neurons of specific thalamic nuclei project to layer(s) (X) of cerebral cortex, with minor projections to layer(s) (Y).

Answer 30

``` X = 4 Y = 6 ```

Question 31

Most cerebral areas receiving thalamic input send feedback projections to (same/different) thalamic nuclei, arising from layer(s) (X).

Answer 31

The same; | X = 5 and 6

Question 32

Number of corticothalamic projections was found to be (greater/smaller) than that of thalamocortical projections by which factor?

Answer 32

Greater; 10

Question 33

Axons of (corticothalamic/thalamocortical) projections produce large, highly effective synaptic boutons. These were termed (modulators/drivers).

Answer 33

Thalamocortical; drivers

Question 34

Reticular nucleus is made up entirely of (X) neurons. Its axons project into (Y).

Answer 34

``` X = inhibitory Y = thalamus ```

Question 35

Pulvinar nucleus of thalamus receives input from (X) and sends output to (Y).

Answer 35

``` X = superior colliculus, primary and non-primary visual cortices Y = Parietal, Occipital, Temporal association cortices ```

Question 36

MD nucleus of thalamus receives input from (X) and sends output to (Y).

Answer 36

``` X = amygdala Y = Prefrontal cortex ```

Question 37

Thalamic relay signal is modulated by which source(s) of inhibitory signals?

Answer 37

1. Dendrodendritic synapses | 2. Reticular nucleus

Question 38

T/F: Most of synaptic composition of LGN is from the retina.

Answer 38

False - from brainstem/cortical areas

Question 39

Anterior limb of internal capsule is sandwiched between which structure(s)?

Answer 39

Lenticular nuclei and head of caudate

Question 40

Posterior limb of internal capsule is sandwiched between which structure(s)?

Answer 40

Lenticular nuclei and thalamus

Question 41

Anterior limb of internal capsule contains fibers that interconnect:

Answer 41

1. Anterior thalamic nucleus with cingulate gyrus 2. MD nucleus with prefrontal cortex 3. Frontal lobe with ipsilateral pontine nuclei

Question 42

Genu of internal capsule contains fibers that interconnect:

Answer 42

1. Frontal lobe with ipsilateral pontine nuclei | 2. VA/VL nuclei with motor/pre-motor cortices

Question 43

Posterior limb of internal capsule contains fibers that interconnect/project:

Answer 43

1. Parietal lobe with ipsilateral pontine nuclei 2. VA/VL nuclei with motor/pre-motor cortices 3. Corticospinal (descending from motor cortex) 4. Somatosensory projections (to and from VPL/VPM)

Question 44

Lenticulostriate arteries arise from (X) artery.

Answer 44

X = middle cerebral

Question 45

Anterior limb of internal capsule blood supply via (X), which arise(s) from (Y).

Answer 45

``` X = Recurrent arteries of Heubner Y = anterior cerebral artery ```

Question 46

Posterior limb of internal capsule blood supply via (X), which arise(s) from (Y).

Answer 46

``` X = lenticulostriate, anterior choroidal, and thalamoperforator arteries Y = middle cerebral, internal carotid, posterior cerebral arteries ```

Question 47

Genu of internal capsule blood supply via (X), which arise(s) from (Y).

Answer 47

``` X = lenticulostriate arteries; Y = middle cerebral artery ```

Question 48

(X) arteries, which supply (Y) part(s) of internal capsule, are particularly prone to narrowing during hypertension.

Answer 48

``` X = lenticulostriate; Y = genu and posterior limb ```

Question 49

Input to anterior nucleus of thalamus.

Answer 49

1. Mammillary bodies via mammillothalamic tract | 2. Hippocampus via fornix

Question 50

Output from anterior nucleus of thalamus.

Answer 50

Cingulate cortex