Thalamus -Bales

Question 1

What are the dorsal tier nuclei of the lateral group (3)?

Answer 1

Pulvinar (most posterior)
Lateral Posterior (LP) 
Lateral Dorsal (LD) (most anterior)

Question 2

What are the ventral tier nuclei from anterior to posterior?

Answer 2

Ventral anterior (VA) 
ventral lateral (VL) 
ventral posterior lateral (VPL) 
ventral posterior medial (VPM) 
Medial and lateral geniculate nuclei (MGN, LGN)

Question 3

What are the nonspecific -arousal nuclei? (2) What are their inputs, projections and functions?

Answer 3

Midline nuc
centromedian nuc

• input: spinal cord, brainstem and reticular formation
• projection: widespread, diffuse projection to cerebral cortex and basal ganglia
• function: regulation of cortical activity and arousal

Question 4

What are the associative nuclei? (3) What are their inputs, projections and functions?

Answer 4

• DM (dorsomedial):
  input: amygdala and entorhinal cortex
  projection: prefrontal cortex
  fxn: affect, emotion, motivation, behavior, olfactory interpretation.

-pulvinar:
Input: retina, pretectum, superior colliculus and visual asscociation areas
projection: occipital, parietal, temporal association cortex.
function: visual integration, interpretation and response

• LP (lateral posterior):
  input: superior colliculus and pretectum
  projection: superior posterior parietal association cortex
  function: visual integration, interpretation and response

Question 5

What are the limbic nuclei? (2) What are their inputs, projections and functions?

Answer 5

• anterior nuc:
  input: maxillary nuc of hypothalamus–>mammillothalamic tract
  projection: cingulate gyrus
  function: relay in Papex circuit of emotion and memory.
• lateral dorsal nuc (LD): inout: hippocampal formation
  projection: cingulate gyrus
  function: limbic functions including emotion.

Question 6

What nuclei are involved in motor planning and control relays? (2) What are their inputs, projections and functions?

Answer 6

ventral anterior nuc. (VA)

ventral lateral nuc. (VL)

both receive input from basal nuclei and cerebellum
projection: premotor supplementary motor cortex (frontal motor cortices)

Question 7

Which nuclei are involved in sensory relay? (4) What are their inputs, projections and functions?

Answer 7

ventral posterior lateral nuc. (VPL):

function: touch, proprioception, pain and temp of limbs and trunk. input: conscious somatosensory from trunk and limbs
projection: somatosensory cortex

ventral posterior medial nuc. (VPM):

function: touch, proprio., temp., pain, taste from head.
input: conscious trigeminothalamic and gustatory pathways
projection: somatosensory cortex for face and anterior insula (taste)

lateral geniculate nuc. (LGN):

function: primary visual perception
input: optic tract
projection: primary visual cortex

medial geniculate nuc. (MGN):

function: primary auditory perception.
input: inferior colliculus
projection: primary auditory cortex

Question 8

What is considered the gatekeeper nucleus? What are their inputs, projections and functions?

Answer 8

reticular nuc:

function: regulate thalamocortical-corticothalamic communication.
input: thalamocortical and corticothalamic collaterals
projection: thalamic nuclei

Question 9

What is Korsakoff syndrome? What causes it and what are some effects?

Answer 9

Bilateral medial degeneration of thalamus in chronic alcoholism accompanied by thiamine deficiency is classic Korsakoff’s syndrome. Effects include anterograde amnesia in addition to behavioral problems

Question 10

Why is it thought that the reticular nucleus plays a role in schizophrenia?

Answer 10

in normal stage 2 sleep, bursts of “sleep spindles” are generated in the reticular nucleus. Schizophrenics don’t have these spindles–> reticular nucleus plays a role in schizophrenia

Question 11

What is the leading cause of thalamic problems?

Answer 11

vascular lesions

Question 12

What supplies the thalamus?

Answer 12

slender, ascending branches of the posterior communicating artery and the posterior cerebral artery (called thalamostriate or thalamoperforate arteries).

Anterior choroidal A. (from MCA) and posterior choroidal A (from PCA) pass posteriorly and arch up around the back end of the thalamus supplying the back and top with blood.

Question 13

What are small, deep infarcts of penetrating aa. to the thalamus called?

Answer 13

Lacunar strokes

Question 14

What can cause a symmetrical bilateral lesion of the paramedian region of the thalamus?

Answer 14

a variation in the artery of Percheron can branch and ascend to both sides of the thalamus–> can cause a bilateral lesion if get infarct here

Question 15

What will a VPL lesion of the thalamus produce?

Answer 15

more specific and less behavioral effects:

contralateral hemianesthesia (VPM, VPL, internal capsule) 
homonymous hemianopia (LGN)

Question 16

What is athetosis?

Answer 16

a movement disorder marked by ceaseless involuntary slow, sinuous, writhing movements, especially in the distal limb.