Thalamus

Question 1

Name the major thalamic nuclei

Answer 1

-anterior
-posterior
-medial
-ventrolateral

Question 2

Through what do the thalamic neurons send axons?

Answer 2

Internal capsule

Question 3

What is the function of the internal capsule of the thalamus?

Answer 3

Each internal capsule carry information to the cortex about the contralateral side of the body

Question 4

How does the cortex send information to lower limbs?

Answer 4

Through the thalamus

Question 5

Where is the thalamus located?

Answer 5

Between the ascending and descending pathways of the brain

Question 6

The thalamus is responsible for sending all sensory information to the cortex except…

Answer 6

Olfactory sensation

Question 7

What does the thalamus act as?

Answer 7

An active relay station

Question 8

How does active relay work?

Answer 8

Nuclei in the thalamus receive information specific to sensory modality and project it to a specific area of the cortex

Question 9

The thalamus modulates the passage of specific information, depending on what?

Answer 9

Depending on the behavior state

Question 10

What plays an important role in the initial processing of information?

Answer 10

Active relay of the the thalamus

Question 11

Where from do the anterior thalamic nuclei receive their input and what is it involved in?

Answer 11

From the hypothalamus and hippocampus and it is involved in memory and emotion

Question 12

Where form do the medial thalamic nuclei receive their input and what is it involved in?

Answer 12

From basal ganglia, amygdala, and midbrain and is involved in memory and emotion

Question 13

Where form do the ventral (anterior and ventral lateral) thalamic nuclei receive their input and what is it involved in?

Answer 13

From basal ganglia and cerebellum, it is involved in motor control

Question 14

Where form do the ventral (posterior lateral) thalamic nuclei receive their input and what is it involved in?

Answer 14

Form the spinal cord, and it is involved in somatosensory information (including pain)

Question 15

Where form do the posterior thalamic nuclei receive their input and what is it involved in?

Answer 15

From the inner ear (medial geniculate) and retina (lateral geniculate), it is involved in hearing and vision

Question 16

Where form do the intralaminar thalamic nuclei receive their input and what is it involved in?

Answer 16

From the spinal cord, brain stem, and cerebellum, and it is involved in cortical arousal! Integration of sensory sub-modalities

Question 17

What forms the outer layer of the thalamus?

Answer 17

The thalamic reticular nucleus (TRN)

Question 18

Name the non specific nuclei (diffuse projection) of the thalamus

Answer 18

-midline nuclei
-intralaminar nuclei
(associated with awareness, wakefulness, consciousness)

Question 19

Where are the axons of TRN terminated ?

Answer 19

on the other thalamic nuclei and not interconnected with the cortex

Question 20

TRN is mostly what type of cells?

Answer 20

Inhibitory GABA cells

Question 21

most thalamic nuclei use what type of neurotransmitters?

Answer 21

Excitatory neurotransmitters (glutamate)
Except for TRN cells they are mostly inhibitory

Question 22

What is the function of TRN?

Answer 22

Modulates the stream of information between the thalamus and the cortex

Question 23

What are the two major neurons of the thalamus (dependent on behavioral context)

Answer 23

-projection neurons
-interneurons

Question 24

What are some characteristics of projection neurons

Answer 24

-long axons that go to layer 4 of the cerebral cortex
-each axon has collaterals that terminate in the reticular nucleus

Question 25

What are some characteristics of interneurons?

Answer 25

-their axons terminate locally within the same nucleus -they process information within that nucleus (inhibit and allow information)

Question 26

What are the two major neurotransmitters that are used by neurons in the thalamus?

Answer 26

-GABA -Glutamate

Question 27

Neurons found in the thalamic reticular nucleus and interneurons

Answer 27

GABA neurons

Question 28

The major neurotransmitter released by thalamic neurons projecting to the cortex

Answer 28

Glutamate

Question 29

Cortex to thalamus projections use what neurotransmitter?

Answer 29

Glutamate

Question 30

What does the the TRN of the thalamus act as?

Answer 30

A filtering system

Question 31

What helps sharpen contrast between stimuli?

Answer 31

Inhibitory inter-neurons within each relay nucleus

Question 32

What are the different mechanisms that underlie lateral inhibition to enhance the contrast between stimuli?

Answer 32

-feed back inhibitory process -feed-forward inhibitory process -distal inhibitory process

Question 33

Where does the distal inhibitory process occur?

Answer 33

-on terminals of primary sensory neurons -on cell bodies of projection neurons

Question 34

Where are higher perceptual and cognitive functions performed?

Answer 34

In the cortex

Question 35

How is the cortex organized?

Answer 35

-Into vertical columns or slabs

Question 36

How is the cortex organized?

Answer 36

Into vertical columns or slabs

Question 37

In what layer of the brain are the vertical columns of the cortex?

Answer 37

They span all six layers from the cortical to the white matter

Question 38

The fundamental computational modulation of the neocortex are …..

Answer 38

Cortical columns

Question 39

Where do all neurons within a column receive input from?

Answer 39

They receive input from the same local area of skin and respond to a single class of receptors

Question 40

All neurons in a column usually respond to what?

Answer 40

They usually respond to only one modality: -touch -pressure -temperature -pain

Question 41

What does the anatomical structure that a column provides do?

Answer 41

It preserves the properties of lactation and modality

Question 42

What does stroke in thalamic area affect?

Answer 42

The nerve fibers in the internal capsule

Question 43

What part of the thalamus conveys neuronal input to and output form the cortex

Answer 43

Internal capsule

Question 44

What happens when there is a lesion in the thalamus?

Answer 44

1-thalamic syndrome 2-the threshold of pain, temperature, and tactile sensation will be raised on the contralateral side of the lesion

Question 45

Explain thalamic syndrome

Answer 45

Somatic modalities are diminished on the contralateral half of the half of the head and body (with no anesthesia)

Question 46

What is the line of communication between the thalamus, brain stem, and spinal cord?

Answer 46

The internal capsule

Question 47

What do the fibers of the internal capsule convey?

Answer 47

Input and output from the cortex