thalamus Flashcards
diencephalon location
between the brainstem and cerebral hemispheres
diencephalon is continuous with …
rostral part of the midbrain
nuclei in diencephalon connect to …
cerebral cortex and limbic areas
diencephalon components
- thalamas
- hypothalamus and pituitary gland
- epithalamus
- subthalamus (ventral thalamus)
epithalamus
- habenular nucleus and habenular commissure
- pineal gland
habenular nucleus and habenular commissure
- connects with limbic system
- serves autonomic function and emotional drives
pineal gland
- endocrine organ
- synthesizes melatonin
- controls sleep/wake cycle and regulation of puberty onset
subthalamus
- subthalamic nucleus (STN)
- field of Forel
inferior surface of diencephalon
- almost entirely surrounded by the cerebral hemispheres
- minor portions visible: tuber cinerum and mammillary bodies
tuber cinerum
a hollow eminence between chiasm and hypothalamus
mammillary bodies
- part of hypothalamus
- help form relay between amygdala and thalamus
thalamus
- large mass of grey matter
- forms the lateral wall of the 3rd ventricle
how is the thalamus seperated from hypothalamus
hypothalamic sulcus
what connects thalamus to opposite thalamus
interthalamic adhesion
what subdivides the diencephalon
hypothalmic sulcus
diencephalon subdivisions
- dorsal part
- ventral part
dorsal diencephalon
- thalamus
- anterior and posterior poles
ventral diencephalon
- hypothalamus
- subthalamus
thalamus lateral boundaries
bounded laterally by caudate nucleus, thalamostriate vein and stria terminalis
stria terminalis
a nerve fiber bundle
thalamus superior boundaries
- between lateral ventricle and thalamus is stratum zonale
- lateral part lies in the floor of the lateral ventricle and is covered by ependyma
thalamus medial boundaries
related to the choroid plexus of the 3rd ventricle
thalamus inferior boundaries
rests on the subthalamus and hypothalamus
anterior pole of diencephalon
posterior wall of interventricular foramen of monro
posterior pole of diencephalon
pulvinar nucleus
pulvinar nucleus
- the largest nucleus of the thalamus
- lateral to pineal gland, habenular, posterior commissures
- superior to lateral and medial geniculate bodies
superior colliculi function
vision
inferior colliculi function
auditory
5 main groups of thalamic nuclei + ? nuclei
- anterior group
- medial group
- posterior group
- lateral group
- ventral group
- intralaminar nuclei
thalamus grey matter divided into nuclei partitions:
- anterior
- medial
- lateral
what seperates the thalamus nuclei partitions
internal and external medullary lamina
external medullary lamina location
laterally, separates reticular nucleus from the rest of the thalamus
what does the external medullary lamina contain
- thalamocortical
- corticothalamic fibers
internal medullary lamina
Y-shaped band, divides thalamus into anterior, medial, lateral nuclear groups
what does the internal medullary lamina contain
- fibers connecting thalamic nuclei with one another
- neuronal collections called intralaminar nuclei
thalamus functions
- relay between subcorticocal areas and cortex
- all sensory systems except olfactory nucleus connect to a nucleus in the thalamus
- balance, hearing, vision, touch, taste
- sleep and wake cycles
- motor systems
all of the nuclei except reticular nucleus project to …
ipsilateral cerebral cortex
anterior group function
part of the limbic system
medial group function
integrates sensory information for projection to frontal lobes
ventral group function
- projects sensory information to the primary sensory cortex
- relays info from cerebellum and basal nuclei to motor area of cerebral cortex
posterior group nuclei
- pulvinar nuclei
- lateral geniculate nuclei
- medial geniculate nuclei
pulvinar nuclei function
integrate sensory info for projection to association areas of cerebral cortex
lateral geniculate nuclei function
project visual info to the visual cortex
medial geniculate nuclei function
project auditory info to the auditory cortex
lateral group function
integrates sensory info and influences emotional states
blood supply of the thalamus
- posterior communicating artery
- posterior cerebral artery
- anterior choroidal artery (LGB)
posterior communicating artery
gives rise to the anterior thalamoperforating arteries
posterior cerebral artery
- gives rise to the posterior choroidal arteries
- gives rise to the posterior thalamoperforating arteries
thalamic reticular nucleus
- occupies key position for thalamocorticoal (TC) and corticothalamic (CT) operations
- located at thalamus-white matter interface between internal capsule and external medullary lamina where TC and CT intersect
- concerned with almost all functional modalities
thalamic reticular nucleus sectors
at least seven:
- five sensory (auditory, gustatory, somatosensory, visceral, visual)
- one motor
- one limbic
reticular formation
- interconnected nuclei found throughout brainstem
- contains ascending and descending reticular formation
reticular formation nuclei list
- dorsal tegmental nuclei
- central tegmental nuclei
- central and inferior nuclei
dorsal tegmental nuclei location
midbrain
central tegmental nuclei location
pons
central and inferior nuclei location
medulla
ascending reticular formation
- reticular activating system
- sleep/wake cycle (alertness levels)
- projects to the mid-line group of the thalamus
descending reticular formation
- posture and equilibrium and ANS activity
- receives info from hypothalamus
- plays a role in motor movement
