THALAMUS

Question 1

What are the 4 major divisions of the diencephalon?

Answer 1

1. Epithalamus (pineal gland,etc)
2. DORSAL THALAMUS (true)
3. Subthalamus
4. Hypothalamus

Question 2

What are the 4 major divisions of the THALAMUS itself?

Answer 2

1. Internal Medullary Lamina
2. Intralaminal Nuclei.
3. Thalamic Reticular Nucleus
4. Midline Nuclei

Question 3

What are the 3 functional groups of the thalamus?

Answer 3

1. Specific/relay
2. Association
3. Non -Specific

Question 4

What various nuclei fall within the 3 functional groups of the thalamus?

1. Specific/Relay
2. Association
3. Non-specific

Answer 4

1. VPL, VPM, VA/VL, MEDIAL GENICULATE, LATERAL GENICULATE, LD (lateral dorsal)
2. • Lateral Posterior
   • Pulvinar
   • Dorsomedial
3. Intralaminar & Reticular

Question 5

What is the function of the RETICULAR NUCLEUS OF THE THALAMUS? Which thalamic functional group does it fall in?

Answer 5

HiGHLIGHT certain novel/new sensory info, and ignore background info
(relays to other areas)

• NON -SPECIFIC group
  (does not relay directly to cortex, only relay to THALAMUS)

Question 6

Which nucleus does not relay directly to the CORTEX, but ONLY to the THALAMUS?

Answer 6

RETICULAR NUCLEUS

Question 7

What are the afferents for the following THALAMIC NUCLEI, where do these nuclei project?

1. VA/VL
2. VPL
3. VPM
4. Medial Geniculate
5. Lateral Geniculate
6. Anterior

Answer 7

1. Basal Ganglia/Cerebellum
2. Medial Lemniscus/ STT of the BODY
3. Medial Lemniscus/ STT of the FACE
4. Inferior Colliculus
5. Optic tract (Superior Colliculus)
6. Mamillothalamic Tract

Question 8

Where do these nuclei project? (efferents)

1. VA/VL
2. VPL
3. VPM
4. Medial Geniculate
5. Lateral Geniculate
6. Anterior

Answer 8

1. Motor Areas (pre-central gyrus + frontal area)
2. Somatosensory cortex
   (AREA 312 of Post-central gyrus)
3. Somatosensory cortex
   (AREA 312 of Post-central gyrus)
4. Auditory cortex (Transverse temporal gyri)
5. Visual Cortex (occipital lobe –> calcarene fissure area 17)
6. CINGULATE gyrus

Question 9

What is the auditory cortex of the brain?

Answer 9

Transverse Temporal Gyrus

Question 10

What is the only sensory information NOT traveling through the Thalamus?

Answer 10

SMELL

Question 11

What is the function of the cerebellum?

Answer 11

coordinates voluntary movements such as posture, balance, coordination, and speech, resulting in smooth, balanced muscular activity.

• makes sure that motor functions you want to do HAPPEN (monitors & adjusts motor function)

Question 12

What is the function of basal ganglia?

Answer 12

Coordination of motor activity between agonist and antagonist

ex: activates the bicep (agonist), i& inactivates the function of the tricep (antagonist)

Question 13

What is the function of the thalamus?

Answer 13

Receives sensory information & passes this on either DIRECTLY or INDIRECTLY
- decides what info to pass on

Question 14

What are the majority of thalamic neurons?

Answer 14

MAJORITY = PROJECTION

rest = inhibitory

Question 15

What type of inputs exist into the THALAMUS? Which of these 2 is the MAJOR input?

Answer 15

1. Specific (ex: medial lemniscus pathway)
   - use GLUTAMATE
2. REGULATORY
   = MAJORITY!!

Question 16

What is the major output and input of the thalamus?

Answer 16

Output = PROJECTION neurons

Input = REGULATORY
control thalamus & turn parts of it on/off

Question 17

which nuclei of the thalamus is split into ANTERIOR, MEDIAL, & LATERAL and forms a Y SHAPE?

Answer 17

INTERNAL MEDULLARY LAMINA

• collection of myelinated fibers

Question 18

The thalamus forms the wall of which structure?

Answer 18

3rd ventricle

Question 19

What is the nuclei that is referred to as the “thin sheet draped over the thalamus”

Answer 19

THALAMIC RETICULAR NUCLEUS

c-shape around the image of the thalamus like a bean

Question 20

Which nuclei are embedded in the Internal medullary Lamina?

Answer 20

INTRALAMINAR Nuclei

Question 21

The thalamus lies behind what structure? it forms the wall of which structure?

Answer 21

1. behind the INTERVENTRICULAR FORAMEN

2. walls of the 3rd VENTRICLE

Question 22

What is the pineal gland responsible for?

Answer 22

Circadian Rhythms, melatonin

Question 23

What separates the thalamus from the lentiform nucleus?

Answer 23

INTERNAL CAPSULE

Question 24

What structures compose the lentiform nucleus? What does it look like?

Answer 24

Putamen & Globus Pallidus

• it is the ball at the end of the CAUDATE

(part of basal ganglia)

Question 25

What makes the decision of which possible behaviors to execute at any given time? (motor function)

Answer 25

LENTIFORM NUCLEUS

Question 26

Which functional group of the thalamus has clear inputs & projections & ALOT OF TOPOGRAPHIC organization?

Answer 26

Specific/Relay Nuclei

Question 27

Which thalamic nuclei is used to project visual info to the visual cortex of the brain (occipital lobe)? Which Brodman's zone is this?

Answer 27

1. LATERAL GENICULATE (SLO AIM) AREA 17 - Calcarene fissure

Question 28

In the thalamus, which Specific/Relay nucleus shows somatotopic organization in regards to the face & the body?

Answer 28

VPM (FACE) & VPL(body) - face is more medial

Question 29

Which nuclei can perform higher level of analysis?

Answer 29

ASSOCIATION NUCLEI 1. Lateral Posterior 2. Pulvinar 3. Medial Dorsal Nuclei

Question 30

Where do the ASSOCIATION NUCLEI receive input from? Do they receive input from sensory info?

Answer 30

DIRECTLY FROM CORTEX - NO INPUT FROM PRIMARY SENSORY INFO (does not project to spinal cord; no SUBCORTICAL organs) - only talks back & forth to cortex

Question 31

``` Which functional nuclei of the thalamus is responsible for consciousness, emotional state etc? 1. Specific 2. Association 3. Non-specific Which nuclei are within this category? ```

Answer 31

NON-SPECIFIC NUCLEI 1. Intralaminar (alertness, sensory awareness) 2. Thalamic Reticular Nuclei

Question 32

Which Non-specific nuclei project ONLY to the thalamus? (not to the cortex or anywhere else)

Answer 32

THALAMIC RETICULAR FORMATION* - can inhibit or excite (look at name)

Question 33

What is the function of the Reticular Formation of the Thalamus?

Answer 33

serves as a FILTER - highlights certain sensory info, turns off info around the area = control flow of info IN & OUT

Question 34

The top of the internal capsule is called what?

Answer 34

Corona Radiata | fibers connect the lentiform nucleus to the caudate

Question 35

What are the 3 divisions of the internal capsule?

Answer 35

1. Anterior Limb 2. GENU (bend) 3. Posterior Limb (mostly sensory)

Question 36

What is the MAIN blood supply to the thalamus?

Answer 36

Posterior Cerebral Artery | PCA - but SMALL Perforating arteries supply the thalamus from PCA

Question 37

If there is hypertension in the perforating arteries, what could occur?

Answer 37

- lose function of the THALAMUS | - lose sensory info from contralateral side of the body

Question 38

What is sensory ataxia?

Answer 38

Loss of proprioception (where the limbs are in relation) - postiive Romberg's sign - can't maintain balance with eyes closed = SENSORY ATAXIA - not cerebellar ataxia

Question 39

If the vision is lost in an individual, which THALAMIC NUCLEI is likely responsible?

Answer 39

Lateral Geniculate Nuclei

Question 40

If a stroke occurs that affects the VPL nucleus? What would be lost?

Answer 40

- loss of PROPRIOCEPTION (vibration/2 pt. touch) on CONTRALATERAL side of the body - (VPM = same side of face)

Question 41

What artery is likely occluded in a LATERAL MEDULLARY STROKE? (Wallenburg Syndrome) If the VPM & VPL were damaged, what symptoms would be apparent?

Answer 41

1. PICA (posterior inferior cerebellar artery) 2. VPM = loss of pain sensation on SAME SIDE of face VPL = loss of sensation on OPPOSITE SIDE OF BODY (contralateral)