The Thalamus Flashcards
Where is the thalamus located?
In the diencephalon, on either side of the third ventricles
What do the two thalami form?
The lateral walls of the third ventricles and the floor of the lateral ventricles
What does the lateral cell group of the thalamus comprise of?
The ventral and dorsal nuclear tiers
Where are the lateral and medial geniculate nuclei located in the thalamus?
At the posterior pole
What is the external medullary lamina composed of?
Thalamocortical and corticothalamic fibres
Where does the reticular nucleus lie?
Between the external medullary lamina and the internal capsule
What are the functional types that thalami nuclei may be categorised into?
Rely or specific, nonspecific or associative nuclei
What are the relay nuclei connected to?
Specific motor and sensory areas of the cerebral cortex
Why are non-specific nuclei termed this?
They are not specific to any one modality
What regions of brain are associative nuclei connected to?
Association areas of cerebral cortex
Where is the anterior nuclear group located?
Anterior portion of thalamus extending to its anterior pole
What is the anterior nuclear group part of?
Papez circuit
Where does the anterior nuclear group receive a large afferent supply from?
The mammillary body of the hypothalamus via the mammilothalamic tract
Where does the anterior nuclear group primarily project to?
The cingulate gyrus
Where is the lateral cell group located?
The ventral nuclear tier
What does the ventral anterior nucleus form?
The cognitive loop of the basal ganglia
Where does the ventral anterior nucleus receive afferent fibres from?
The ipsilateral globus pallidus
Where do fibres from the ventral anterior nucleus project fibres to?
The prefrontal and premotor cortices
What does the ventral lateral nuclues form?
Part of the motor loop of the basal ganglia
Where does the anterior part of the ventral lateral nucleus receive fibres from?
The ipsilateral globus pallidus
Where does the anterior ventral lateral nucleus project fibres to?
The supplementary motor cortex
Where does the posterior part of the of the ventral lateral nucleus receive fibres from?
From contralateral cerebellum via the dentatorubrothalamo-cortical tract
Where does the posterior part of the ventral lateral nucleus project fibres to?
The primary motor cortex
Where does the ventral posterior nucleus receive fibres from?
All fibres carrying general sensory information via medial, spinal and trigeminal lemnisci
Where do fibres from ventral posterior nuclei project to?
The somato-sensory cortex
What are the ventral posterior nuclei subdivided into?
the ventral posterolateral and ventral posteromedial nuclei
Where does the lateral geniculate body receive fibres from?
Retinal fibres via the optic tract
Where do fibres from the lateral geniculate nucleus project to?
The primary visual cortex via optic radiation
What is the fxn of the medial geniculate nucleus?
The main thalami nuclei of the auditory pathway
Where are the intralaminar nuclei located?
Embedded into the internal lining of the medullary lamina of the thalamus
What is the anterior nucleus of the intralaminar nuclei part of?
The limbic-cingulate circuit- part of emotion loop
What is the fxn of the medial dorsal nuclei of the intralaminar nuclei?
forms feedback loop with the frontal cortices to maintain level of wakefulness in executive frontal processing areas
What is the fxn of the centromedian nucles of the intralaminar nuclei?
forms feedback loop with frontal and basal ganglia for motor alertness
What does the anterior peduncle connect the thalamus to?
The prefrontal cortex and cingulate gyrus
What does the superior peduncle attach the thalamus to?
Premotor, motor and somatic sensory cortex
What does the posterior peduncle connect the thalamus with?
The occipital lobe and posterior parts of the parietal and temporal lobes
Where does the inferior peduncle reach to?
The temporal and orbital cortex
