The Diencephalon Flashcards
what is the diencephalon located between?
the midbrain and hypothalamus
what is the central diencephalon?
the thalamus
what are the 3 parts of the diencephalon?
the thalamus
the prethalamus
the pretectum
where is the prethalamus in relation to the thalamus?
in front of the thalamus
where is the pretectal area in relation to the thalamus?
behind the thalamus
what does diencephalon mean?
‘interbrain’
what does the diencephalon link?
the main parts of the forebrain with the brainstem
what does prosomere 1 include?
the pretectal area
what does prosomere 2 include?
the thalamic area
what does prosomere 3 include?
the prethalamus
in development, in what direction is the hypothalamus in relation to the thalamus?
rostral
why is the thalamus dorsal to the hypothalamus?
because of the sharply bent neuraxis at the midbrain during development (the cephalic flexure)
what is the sharp flexure in the neuraxis at the midbrain known as?
the cephalic flexure
what sensory systems does the thalamus receive input from?
all but the olfactory system
where does the visual pathway terminate in the thalamus?
in the dorsal lateral geniculate nucleus (DLG)
where does the dorsal lateral geniculate nucleus end up projecting to?
the visual cortex
where does the auditory pathway terminate in the thalamus?
the medial geniculate nucleus (MG)
where does the medial geniculate nucleus end up projecting to?
the auditory cortex
where does the touch pathway terminate in the thalamus?
the ventroposterior nucleus (VP)
where does the ventroposterior nucleus end up projecting to?
the somatosensory/touch cortex
movement information from the cerebellum reaches where in the thalamus?
the ventrolateral nucleus
where does the ventrolateral nucleus send information to?
the primary motor cortex
what is the main part of the cortex concerned with motor control?
the primary motor cortex
where is the habenular nuclei?
on the dorsomedial edge of the thalamus
what thalamic nucleus is attached to the stalk of the pineal gland?
the habenular nuclei
what does the pineal gland secrete?
melatonin
what does melatonin secreted by the pineal gland influence?
the sleep cycle
what is the most rostral diencephalic prosomere?
p3
what important motor control region does p3 contain?
the zona incerta
In Parkinson’s, stimulating electrodes inserted in the zona incerta can do what?
minimize tremors + muscle stiffness
what is it called when stimulated electrodes are inserted into the zona incerta?
deep brain stimulation (DBS)
what nucleus in p3 plays a role during sleep?
the reticular nucleus
what do the reticular nuclei do?
play a role during sleep by controlling output from the thalamus to the cortex.
p3 neurons are inhibitory, therefore they are:
GABAergic
after sleep is established, the p3 GABAergic neurons take control of what?
main thalamic nuclei activity
after sleep is established, the p3 GABAergic neurons take of the4 main thalamic nuclei activity to do what?
to set up a rhythmic wave pattern of electrical activity in the cortex
what is the most caudal diencephalic prosomere?
p1
what do pretectal area nuclei play a role in?
visual reflexes
at nuclei does p1 contain?
the pretectal area nuclei
what is the prominent p1 landmark at the junction of the prethalamus and midbrain?
the posterior comissure
what does the posterior commissure belong to?
p1
