Thalamus Flashcards
In the basic pathway of sensory interpretation, what is the general function of the thalamus?
Helps make a “decision” on what do to with the ascending info (analyzes it) before it goes to consciousness (“decides” what info passes)
- Different sensory modalities come together here
What 2 major brain regions can thalamic output go to?
- Cerebrum
- Striatum
What are the parts of the striatum?
Caudate nuc. + putamen
What are 2 major e.g.’s of sensory info that does NOT go to the thalamus?
- Olfaction
- Unconscious proprioception (str8 to cerebellum)
Besides ascending sensory info, what other major category of info does the thalamus receive?
What 2 major brain regions might provide this info to the thalamus?
Motor
- E.g. from cerebellum and basal ganglia
What’s the proper name of the thalamus?
Dorsal thalamus
Name the divisions of the diencephalon.
- Epithalamus
- Dorsal thalamus
- Subthalamus
- Hypothalamus
What is contained w/in the epithalamus?
Pineal gland, habenula, stria medullaris
What is contained w/in the subthalamus?
Subthalamic nuclei, zona incerta
What are the 4 major thalamic divisions?
Which one divides into 3 more?
Which looks like a thalamic cape and acts as a filter?
- Internal medullary lamina (divides into 3)
- Intralaminar nuclei (w/in lamina)
- Midline nuclei
- Thalamic reticular nuclei (cape/filter-specificity)
Name the 3 divisions of the internal medullar lamina.
What is the shape of the lamina that divide them?
- Anterior division nuclei
- Lateral division nuclei
- Medial division nuclei
(Y-shaped)
Which ventricle does the thalamus form a wall? Which of said ventricle’s walls does it form?
- 3rd ventricle’s lateral wall
The internal capsule divides the thalamus from the _________________.
Which is medial/lateral?
Lentiform nucleus
- Thalamus is medial
Which ventricular space can be found superior to the thalamus?
Body of lateral ventricle (x2)
What can be found superolateral to the thalamus, adjacent to the body of the lateral ventricle?
Caudate nucleus
What are internal capsule fibers known as before they become the internal capsule?
Corona radiata
The thalamus consists of a majority of ________ neurons but also _______ neurons.
(what NT would each of these typically use?)
- Projection (glutamate)
- Inhibitory (GABA)
The majority of thalamic input can be considered __________ but there is also some __________ input.
- Regulatory (e.g. cortex, thalamic reticular nucleus, reticular formation, aminergic projections)
- Specific (e.g. DCP)
What are the 3 grouping of thalamic nuclei? Differentiate them.
- Specific or relay nuclei–*well-defined input and projections
- Association nuclei–*reciprocally connected to association cortex
- Non-specific nuclei–*project to broad areas of cortex
As noted in the homunculus, the VPM of the thalamus relays to what part of the body? What about the VPL?
- Head, tongue (VPM receives from CN V)
- Everything else (VPL receives from DCP/SST)
(looks like man on his knees, sticking out tongue towards medial)
Specific/relay nuclei have specificity but they also _______________ w/each other.
Collaborate
The anterior nucleus, ventral anterior/ventral lateral nucleus, VPM, VPL, MGN, LGN of thalamus fit into which category of thalamic nuclei?
Specific or relay nuclei
What are 2 major association areas of the cerebrum that association nuclei might project to?
Can they project back to the thalamus?
- Prefrontal cortex
- Parietal-occipital-temporal cortex
- Yes, these areas can project back to association nuclei of thalamus
What 3 brain regions might give regulatory input to the relay/specific or association nuclei?
- Cerebral cortex
- Reticular formation
- Reticular nucleus
The pulvinar, dorsomedial, and lateral posterior thalamic nuclei fit into which category of thalamic nuclei?
Association nuclei
Intralaminar and thalamic reticular nuclei fit into which category of thalamic nuclei?
Non-specific nuclei
What are some e.g.’s of specific inputs to specific/relay thalamic nuclei? (brain region, not tract)
Subcortical sites (basal ganglia, cerebellum, retina, sc…)
Which of the 3 types of thalamic nuclei might be the ones that would wake up or relax the cortex?
Nonspecific nuclei (diffuse projections) - E.g. thalamic reticular or intralaminar nuclei
Internal capsule fibers coming in from the cortex area to the thalamus are called what?
Thalamocortical fibers
there are also dentatothalamocortical fibers
What are the 4 different types of thalamic peduncles that can be found w/dissection?
Sup, inf, ant, post (they go in those directions)
What gives input to the VA/VL nuclei of the thalamus?
Basal ganglia, cerebellum
Where do thalamic VA/VL nuclei project?
Motor areas (precentral gyrus, adjacent frontal areas)
What gives input to the VPL nuclei of the thalamus?
Medial lemniscus, spinothalamic tract (spinal components)
Where do thalamic VPL nuclei project?
Somatosensory cortex (postcentral gyrus)
What gives input to the VPM nuclei of the thalamus?
Medial lemniscus, spinothalamic tract (trigeminal components)…AKA chief sensory nuc of V and spinal nucleus of V
Where do thalamic VPM nuclei project?
Somatosensory cortex (postcentral gyrus)
What gives input to the MGN nuclei of the thalamus?
Brachium of inferior colliculus
Where do thalamic MGN nuclei project?
Auditory cortex (transverse temporal gyrus)
What gives input to the LGN nuclei of the thalamus?
Optic tract
Where do thalamic LGN nuclei project?
Visual cortex (occipital lobe)
What gives input to the anterior nuclei of the thalamus?
Mammillothalamic tract
Where do thalamic anterior nuclei project?
Cingulate gyrus
What aa. generally supply the thalamus?
Perforating aa.
Thalamoperforating or thalamogenicular aa. typically branch from what a.?
Posterior cerebral a. (end of basilar a.)
CVA to anterior thalamus would cause what deficits? (I think memorize)
Language (dominant) and memory
CVA to lateral thalamus would cause what deficits? (I think memorize)
Motor and sensory
CVA to medial thalamus would cause what deficits? (I think memorize)
Vigilance, arousal, memory
CVA to posterior thalamus would cause what deficits? (I think memorize)
Higher visual
