DIENCEPHALON DIENCEPHALON
Prof. Dr. Selda Önderoğlu
Prof. Dr. Selda Önderoğlu
DIENCEPHALON DIENCEPHALON
Diencephalon is the part of CNS located on both sides of 3rd
ventricle. Extends ant.ly from
interventricular
foramen postly to cerebral
aequaduct.
PARTS OF DIENCEPHALON PARTS OF DIENCEPHALON
Thalamus,
Hypothalamus,
Epithalamus
Subthalamus
Thalamus Thalamus
part of part of
diencephalon diencephalon
located deeply located deeply in the cerebral in the cerebral
hemispheres hemispheres
Shape: egg Shape: egg
Gray matter Gray matter
Thalamus Thalamus
Relations:
Ant.:
Head of caudate nucl.+
genu of internal capsule
Ant. End forms the post. Border of interventricular foramen
Post.:
Pulvinar of thalamus
Surfaces of thalamus Surfaces of thalamus
Medial surface
Lateral surface
Superior surface
Inferior surface
medial surface medial surface
Forms the upper part of lateral wall of 3rd ventricle
interthalamic mass
(adhesion)
Lateral surface Lateral surface
Posterior limb of internal capsule
Seperated from
lentiform nucleus
by internal capsule
Superior surface Superior surface
Terminal Sulcus (superior
Thalamostriate vein and stria terminalis
courses here)
inferior surface inferior surface
Ant.
Separated from Hypothalamus by hypothalamic sulcus
post
Tegmentum of
Mesencephalon
Internal structure Internal structure
Gray matter ( nueorn groups, nuclei)
White matter ( internal and external
medullary lamina)
Internal Medullary Lamina and Internal Medullary Lamina and
External Medullary Lamina
External Medullary Lamina
Nuclei of Thalamus Nuclei of Thalamus
anterior
medial
Ventral
(VPM&VPL)
dorsal
Posterior(in pulvinar)
Median
intralaminar
reticular
Anterior nuclei Anterior nuclei
Located in the anterior tubercle of thalamus located ant.
thought to be related to
memory
Ventral Nuclei of Thalamus Ventral Nuclei of Thalamus
ventral anterior ventral lateral ventral post.
Posteromedial
Posterolateral
Posteroinferior
Metathalamus Metathalamus
lateral
geniculate body
medial
Geniculate
body
Medial Geniculate body Medial Geniculate body
Related to auditory pathways by the Brachium of inf.
Colliculus it is connected to
lateral lemniscus ( afferent) and send stimuli to the auditory
center in cerebral cortex ( 41- 42 of Brodman areas) (efferent)
Lateral Geniculate body Lateral Geniculate body
Relay nuclei related to vision Afferent fibers from retina
and c superior colliculus Efferent fibers
to Brodmann 17
Functions of Thalamus Functions of Thalamus
Conveys impulses related to different sensations to cerebral sensory center (cortex).
Fibers from cerebellum, basal ganglia, peripheral sensory organs fist go to thalamus modified there and then goes to cerebral cortex.
Sense of smell first goes to its center in cortex, then relays in thalamus.
