09b: Thalamus Flashcards
Ventricular structure separating R/L thalamus.
Third ventricle
(X) is the major part of the diencephalon. Which groups of structures lie near (X) and are also part of diencephalon?
X = thalamus
- Epithalamus (dorsal/caudal)
- Subthalamus (ventral)
- Hypothalamus (below)
Major structures of epithalamus.
- Pineal gland
- Posterior commissure
- Habenular nuclei
(X) is a midsaggital endocrine gland in diencephalon that secretes (Y).
X = pineal; Y = melatonin
Melatonin secreted at high levels during (day/night) and is triggered by (X) signals.
Night
X = visual
(X) is a fiber tract, part of epithalamus, that connects (Y) with their contralateral homologues.
X = posterior commissure; Y = oculomotor nuclei and pretectal nuclei
Formal name of the “thalamus” is:
Dorsal thalamus
The (X) is a fiber layer that divides thalamus into which main parts/compartments?
X = internal medullary lamina;
- Anterior
- Medial
- Lateral
Anterior compartment of thalamus contains:
Anterior nucleus
Medial compartment of thalamus contains:
Mediodorsal nucleus
The (X) compartment of thalamus is divided into which tiers?
X = lateral
- Dorsal
- Ventral
- Appended
Dorsal tier of (X) thalamic compartment contains (Y).
X = lateral; Y = pulvinar nucleus
T/F: Pulvinar, aka “pillow”, nucleus of thalamus stains poorly with myelin.
True
Ventral tier of (X) thalamic compartment contains (Y).
X = lateral Y = VPL, VPM, VA, VL nuclei
(Rostrally/caudally) in thalamus, the VPL/VPM complex is replaced by VA/VL complex.
Rostrally
What are the Appended nuclei of the (X)?
X = thalamus (lateral compartment)
MGN and LGN
(MGN/LGN) is more caudal than (MGN/LGN) and can be observed laterally to (superior/inferior) colliculus.
MGN; LGN;
Superior
List categories of thalamic nuclei, based on functional organization.
- Primary sensory nuclei
- Motor relay nuclei
- Association nuclei
- Limbic nuclei
List the primary sensory nuclei of the thalamus. List respective modality carried by each.
- LGN (Vision)
- MGN (Audition)
- VPL (Somatosensory for body)
- VPM (Somatosensory for face)
List the motor relay nuclei of the thalamus. They carry info from (X) to (Y).
VA/VL Complex;
X = cerebellum and basal ganglia Y = primary motor and premotor cortices
Cerebellar input to (X) nuclei in thalamus comes from which specific part of cerebellum?
X = VA/VL
Dentate nucleus
Basal ganglia, specifically (X), is source of input to (Y) nuclei in thalamus.
X = GP and SNpr (pars reticularis) Y = VA/VL
Association nuclei of thalamus receive (low/high) processed signals from (X), and project to (Y).
High;
X = association regions of cerebral cortex
Y = (back to) cerebral cortex
List the association nuclei of the thalamus.
- Pulvinar
2. Mediodorsal (MD)
List the limbic nuclei of the thalamus.
Anterior nucleus
Anterior nucleus receives some input from (X) via fornix and sends output to (Y).
X = hippocampus Y = cingulate cortex
The “non-specific” nuclei of the thalamus are likely part of (X) system.
X = reticular activating
T/F: All sensory signals travel through thalamus before reaching cerebral cortex.
False - all except olfaction
The majority of neurons in thalamus are (short/long)-range, (excitatory/inhibitory) (X) neurons. The remainder are (Y) neurons.
Long; excitatory;
X = relay
Y = local, inhibitory (GABAergic) interneurons
Most output neurons of specific thalamic nuclei project to layer(s) (X) of cerebral cortex, with minor projections to layer(s) (Y).
X = 4 Y = 6
Most cerebral areas receiving thalamic input send feedback projections to (same/different) thalamic nuclei, arising from layer(s) (X).
The same;
X = 5 and 6
Number of corticothalamic projections was found to be (greater/smaller) than that of thalamocortical projections by which factor?
Greater; 10
Axons of (corticothalamic/thalamocortical) projections produce large, highly effective synaptic boutons. These were termed (modulators/drivers).
Thalamocortical; drivers
Reticular nucleus is made up entirely of (X) neurons. Its axons project into (Y).
X = inhibitory Y = thalamus
Pulvinar nucleus of thalamus receives input from (X) and sends output to (Y).
X = superior colliculus, primary and non-primary visual cortices Y = Parietal, Occipital, Temporal association cortices
MD nucleus of thalamus receives input from (X) and sends output to (Y).
X = amygdala Y = Prefrontal cortex
Thalamic relay signal is modulated by which source(s) of inhibitory signals?
- Dendrodendritic synapses
2. Reticular nucleus
T/F: Most of synaptic composition of LGN is from the retina.
False - from brainstem/cortical areas
Anterior limb of internal capsule is sandwiched between which structure(s)?
Lenticular nuclei and head of caudate
Posterior limb of internal capsule is sandwiched between which structure(s)?
Lenticular nuclei and thalamus
Anterior limb of internal capsule contains fibers that interconnect:
- Anterior thalamic nucleus with cingulate gyrus
- MD nucleus with prefrontal cortex
- Frontal lobe with ipsilateral pontine nuclei
Genu of internal capsule contains fibers that interconnect:
- Frontal lobe with ipsilateral pontine nuclei
2. VA/VL nuclei with motor/pre-motor cortices
Posterior limb of internal capsule contains fibers that interconnect/project:
- Parietal lobe with ipsilateral pontine nuclei
- VA/VL nuclei with motor/pre-motor cortices
- Corticospinal (descending from motor cortex)
- Somatosensory projections (to and from VPL/VPM)
Lenticulostriate arteries arise from (X) artery.
X = middle cerebral
Anterior limb of internal capsule blood supply via (X), which arise(s) from (Y).
X = Recurrent arteries of Heubner Y = anterior cerebral artery
Posterior limb of internal capsule blood supply via (X), which arise(s) from (Y).
X = lenticulostriate, anterior choroidal, and thalamoperforator arteries Y = middle cerebral, internal carotid, posterior cerebral arteries
Genu of internal capsule blood supply via (X), which arise(s) from (Y).
X = lenticulostriate arteries; Y = middle cerebral artery
(X) arteries, which supply (Y) part(s) of internal capsule, are particularly prone to narrowing during hypertension.
X = lenticulostriate; Y = genu and posterior limb
Input to anterior nucleus of thalamus.
- Mammillary bodies via mammillothalamic tract
2. Hippocampus via fornix
Output from anterior nucleus of thalamus.
Cingulate cortex
