Thalamus - nuclei

Question 1

Thalamus - basic anatomy overview

Answer 1

Gray matter

L and R thalamus separated by 3rd ventricle and wedged between basal ganglia structures

all fibers go through the internal capsule from the thalamus

Question 2

Function of Thalamus (4)

Answer 2

1. Emotional tone/affect
   - via limbic system & prefrontal lobe connections
2. Arousal
   - via reticular formation connections
3. Motor - receive and processes all internal motor systems
4. Sensory
   - receives all sensory input EXCEPT olfactory

Question 3

Regional zones based on function (4)

Answer 3

Anterior = affective
Medial = arousal
Lateral = motor
Posterior = sensory

Question 4

Anterior Nucleus

• what does it relay
• connections

Answer 4

relays info from subcortical limbic structures to cortical limbic structures (cingulate gyrus)

Contributes to emotional tone

Connected to limbic lobe

Question 5

Dorsomedial Nucleus (DM)

• what does it contribute to
• where does it relay info

Answer 5

contributes to judgement & reasoning

Relays information to and from the prefrontal cortex

Question 6

Ventral anterior nucleus

• contributes to?
• relays to and from?

Answer 6

Important for motor planning & regulation

relays info from globus pallidus of BG to motor areas

Question 7

Ventral Lateral nucleus

• contributes to?
• relays to and from?

Answer 7

contributes to motor output regulation

relays info from cerebellum and globus pallidus of BG to the M1

Question 8

Ventral Posterior nucleus

• contributes to
• relays to and from?

Answer 8

contributes to sensation

relays info to sensory areas of the cortex (postcentral gyrus)

VPL & VPM = somatosensory info
VPI = vestibular

** just know VP

Question 9

Pulvinar nucleus

• contributes to
• relays info to and from

Answer 9

contributes to perceiving different senses together b/c relays info to the secondary sensory areas

Relays info among cortical association cortices
- areas 5/7 (S2) and 39/40 (SAA)

–> parietal-occipital-temporal cortex

Question 10

Lateral Geniculate Nucleus (LGN)

• contributes to
• relays to and from

Answer 10

contributes to vision

relays visual info to primary visual cortex (area 17 of occipital lobe)

Question 11

Medial Geniculate Nucleus (MGN)

• contributes to?
• relays to and from

Answer 11

contributes to hearing

relays info to primary auditory cortex (area 41)

Question 12

Intralaminar, centromedian & midline nuclei

• contributes to
• relays to and from

Answer 12

contributes to arousal

relays arousal info from reticular system to widespread areas of the brain

Question 13

Internal capsule

- 3 areas

Answer 13

contains motor & sensory tracts, white matter, that connects to the thalamus

1. Anterior = affective
   - judgement, reasoning, affective emotional expression
2. Genu = motor
3. Posterior = motor & sensory
   - motor cortex to BS and SC
   - sensory info from thalamus to different cortical areas

Question 14

Thalamic Pain Syndrome

• where is infarct
• symptoms
• treatment

Answer 14

infarct in VPL of thalamus

Symptoms: spontaneous burning pain & other abnormal sensations
- location & intensity varies

Treat w/ narcotic analgesic, antidepressant or antiseizure meds

Question 15

Spinal Pathways that synapse in the thalamus (4)

Answer 15

1. Spinothalamic - synapses in intralaminar and VP nucleus
2. Dorsal column - synapses in VP
3. Auditory pathway - synapses in MGN
4. Visual - synapses in LGN