36 Diencephalon - Organization and function of thalamus and hypothalamus Flashcards
List the parts of the diencephalon.
- hypothalamus (front + inferior)
- epithalamus (posterior)
- subthalamus
- thalamus (middle)
What is the main role of thalamus?
As a relay center
_____________ separates the thalamus and the hypothalamus.
Hypothalamic sulcus
______________ is the posterior limit of the floor of the diencephalon.
Mamillary body
What are the superior boundaries of the diencephalon?
Connective tissues and choroid plexus of Tela choroidea
What are the 2 layers of white matter in the diencephalon?
- Internal medullary lamina
2. External medullary lamina
Internal medullary lamina separates?
The medial group of thalamic neurons from the lateral group
- also encloses the anterior thalamic nucleus
In the internal medullary lamina, there are some neurons dispersing in the layer to form the ________________, which relays ________signals from the spinoreticulothalamic tract to almost whole area of the cerebral cortex.
Intralaminar nucleus;
emotional
In the internal medullary lamina, there are some neurons dispersing in the layer to form the Intralaminar nucleus, which relays emotional signals from the _______________ to _______________.
spinoreticulothalamic tract;
almost whole area of the cerebral cortex
Pain, temperature and proprioception are relayed to the _______________thalamic nucleus of the diencephalon.
Ventral posterior
What is lateral to the external medullary lamina?
internal capsule and globus pallidus
How can the thalamic nucleus be categorized into 3 types? Give examples of each type.
- Specific relay nuclei
- VA, VL, VP - Association nuclei
- anterior nucleus, mediodorsal nucleus, pulvinar - Non-specific nuclei
- intralaminar nuclei, thalamic reticular nucleus
Afferent and efferent of Ventral anterior nucleus.
Afferent: globus pallidus
Efferent: prefrontal cortex
Afferents and efferents of Ventral lateral nucleus. (2 pairs)
Afferent 1: globus pallidus
Efferent 1: supplementary motor area
Afferent 2: cerebellum
Efferent 2: motor cortex
Afferents and efferent of Ventral posterior nucleus (VPL and VPM).
Afferents: medial, spinal and trigeminal lemnisci
Efferects: somatosensory cortex
Afferent and efferent of lateral geniculate nucleus.
Afferent: Optic tract (superior colliculus of midbrain)
Efferent: Primary visual cortex (visual area of occipital cortex)
Afferent and efferent of medial geniculate nucleus.
Afferent: Inferior branchium (inferior colliculus of midbrain)
Efferent: Primary auditory cortex (superior temporal lobe)
Which thalamic nucleus receives signals from dorsal column tract and spinothalamic tract?
Ventral posterolateral nucleus
Which thalamic nucleus receives signals from head and neck and trigeminal thalamic pathways?
Ventral posteromedial nucleus
_____________ are reciprocally connected to the association areas of the cerebral cortex.
Association nuclei
Afferent and efferent of anterior nucleus.
Afferent: mamillary body
via mammillothalamic tract
Efferent: cingulate cortex
Function of anterior nucleus?
Memory, limbic system
Afferent and efferent of Lateral dorsal nucleus/ Dorsolateral nucleus ?
Afferent: hippocampus
Efferent: cingulate cortex
Function of lateral dorsal nucleus?
Memory
Afferent and efferent of mediodorsal nucleus?
Afferent: olfactory cortex, amygdala in temporal lobe
Efferent: prefrontal cortex (reciprocal)
Function of mediodorsal nucleus
Mood, cognition, judgement (limbic)
Afferent and efferent of lateral posterior nucleus and pulvinar?
Afferent: superior colliculus (midbrain)
Efferent: Visual and parietal association cortices
Functions of lateral posterior nucleus and pulvinar?
Extrageniculate visual pathway, blindsight (lesion at visual cortex > still know whether light is on)
Which association nuclei are involved in the limbic system?
A. anterior nucleus
B. lateral dorsal nucleus
C. mediodorsal nucleus
D. pulvinar and lateral posterior nucleus
C
Afferents and efferents of intralaminar nuclei?
Reticular formation, spinothalamic tracts, trigeminothalamic tracts
»
cerebral cortex and corpus stiratum
Functions of intralaminar nucelis?
Consciousness and arousal, emotional component of pain
____________ cortex is important for the perception of the emotional part of the brain.
Anterior cingulate
Thalamic reticular nucleus is a group of ____________ neurons that form thin layers on the lateral side of the thalamus.
GABAergic
Briefly know about hypothalamic nuclei (low chance to be examined )
- Anterior (above the optic chiasm) : preoptic, supraoptic, suprachiasmatic
- Middle (above the infundibulum) : paraventricular, dorsomedial, lateral ,ventromedial, arcuate
- Posterior (above the tuber cinereum+ mammillary body): posterior, mammillary, tuberomammillary, dorsal
Medial forebrain bundle carries _________ fibers from brainstem to the cerebral cortex. Why is it highly activated in drug addicts, alcoholics?
aminergic = dopaminergic, cholinergic
- includes axons coming from the ventral tegmental areas in the midbrain that projects anteriorly to the nucleus accumbens in the frontal cortex, which uses dopamine as neurotransmitters.
Medial forebrain bundle is medial/ lateral to the hypothalamic neurons.
lateral
The ___________system involves in the regulation of anterior pituitary hormones secretion (adenohypophysis). It includes the ______________ tract that involves preoptic, ventromedial and arcuate nuclei.
parvocellular;
tuberoinfundibular
he ___________system involves in the regulation of posterior pituitary hormones secretion (neurohypophysis). It includes the ______________ tract formed by paraventricular and supraoptic nuclei.
magnocellular;
hypothalamohypophyseal
What is the parasympathetic response upon stimulating the hypothalamus on the urinary bladder?
contraction of bladder
What is the sympathetic response upon stimulating the lateral part of hypothalamus?
Stress-like response:
- diffuse sympathetic discharge
- increase adrenal medullary secretion
____________ are brain regions where the BBB is incomplete, with fenestrated capillaries.
Circumventricular organs
Give example of a prominent circumventricular organ.
area of postrema: located in the 4th ventricle ;
others: pineal body, subfornical organ, median eminence, neurohypophysis, vascular organ of lamina terminalis
