thalamus objectives - michael

Question 1

define Epithalamus:

Answer 1

pineal gland and habenular nuclei

a) Pineal gland: releases melatonin in a circadian rhythm, important for sleep-wake cycles; controlled by sympathetic
b) Habenula: limbic relay nuclei involved in “negative reward” by decreasing activity in dopaminergic neurons; projects to the brainstem

Question 2

define Subthalamus:

Answer 2

subthalamic nucleus and zona incerta; associated with the basal ganglia

Question 3

(Dorsal) thalamus

Answer 3

location in the lateral wall of the third ventricle; has a “burst mode” which generates cortical EEGs and a “tonic mode” which conveys information

Question 4

Relay nuclei:

Answer 4

filter sensory information (e.g. VPL, VPM, VL, VA, metathalamus)

Question 5

Association nuclei:

Answer 5

projection to association cortex; involved in complex functions like attention, memory, eye movements

Question 6

Intralaminar nuclei:

Answer 6

less focused outputs to cortex

Question 7

Reticular thalamic nucleus:

Answer 7

involved in inhibitory feedback

Question 8

Specific thalamic “relay” nuclei:

Answer 8

a) VPL (ventral posterolateral): medial lemniscal input and spinothalamic input (relay)
b) VPM (ventral posteromedial): trigeminothalamic input (relay)
c) VL (ventral lateral): receives cerebellum (dentate nucleus) input, projects to primary motor area (relay)
d) VA (ventral anterior): receives basal ganglia, projects to premotor cortex, plans movements (relay)
e) LG (lateral geniculate): receives optic tract, projects to primary visual cortex (relay)
f) MG (medial geniculate): receives auditory afferents from inferior colliculus, projects to primary auditory cortex (relay)

Question 9

Specific thalamic “association” nuclei:

Answer 9

a) Pulvinar and lateral posterior (LP): receives superior colliculus, projects to secondary visual areas and parietotemporal, contributes to visual perception and eye movements (association)
b) Anterior nucleus and lateral dorsal (LD): receives hippocampus and mammillary bodies, projects to posterior cingulate cortex, role in emotional learning (association)
c) Lateral MD and intralaminar: receives superior colliculus, olfactory cortex, ventral pallidum, projects to frontal eye fields and anterior cingulate cortex; controls eye movements and attention (association)
d) Medial MD and midline: receives solitary nucleus, substantia nigra reticulate, amygdala, ventral pallidum, projects to limbic areas, involved in autonomic regulation and emotions, damage can impair memory

Question 10

Reticular Activating System (ARAS):

Answer 10

responsible for going from inattentiveness to alert, involves midbrain reticular formation, thalamus (intralaminar nuclei) and some diffuse cortex. Damage to ARAS can mean loss of ability to maintain consciousness

Question 11

Intralaminar (centromedian) nucleus:

Answer 11

receives globus pallidus, part of basal ganglia feedback, may be involved in motor functions

Question 12

Reticular thalamus nucleus:

Answer 12

receives cortex and brain stem input, has inhibitory output to the thalamic nuclei, regulatory function 

Question 13

VPL (ventral posterolateral):

Answer 13

medial lemniscal input and spinothalamic input (relay)

Question 14

VPM (ventral posteromedial):

Answer 14

trigeminothalamic input (relay)

Question 15

VL (ventral lateral):

Answer 15

receives cerebellum (dentate nucleus) input, projects to primary motor area (relay)

Question 16

VA (ventral anterior):

Answer 16

receives basal ganglia, projects to premotor cortex, plans movements (relay)

Question 17

LG (lateral geniculate):

Answer 17

receives optic tract, projects to primary visual cortex (relay)

Question 18

MG (medial geniculate):

Answer 18

receives auditory afferents from inferior colliculus, projects to primary auditory cortex (relay)

Question 19

Pulvinar and lateral posterior (LP):

Answer 19

receives superior colliculus, projects to secondary visual areas and parietotemporal, contributes to visual perception and eye movements (association)

Question 20

Anterior nucleus and lateral dorsal (LD):

Answer 20

receives hippocampus and mammillary bodies, projects to posterior cingulate cortex, role in emotional learning (association)

Question 21

Lateral MD and intralaminar:

Answer 21

receives superior colliculus, olfactory cortex, ventral pallidum, projects to frontal eye fields and anterior cingulate cortex; controls eye movements and attention (association)

Question 22

Medial MD and midline:

Answer 22

receives solitary nucleus, substantia nigra reticulate, amygdala, ventral pallidum, projects to limbic areas, involved in autonomic regulation and emotions, damage can impair memory