Download THALAMUS

DIENCEPHALON
Prof. Dr. Selda Önderoğlu

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
Thalamus,
Hypothalamus,
Epithalamus
Subthalamus
Thalamus
 part
of
diencephalon
 located deeply
in the cerebral
hemispheres
 Shape: egg
 Gray matter
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
 Medial
surface
 Lateral surface
 Superior surface
 Inferior surface
medial surface
Forms the upper part of lateral
wall of 3rd ventricle
interthalamic mass
(adhesion)
Lateral surface

Posterior limb of
internal capsule

Seperated from
lentiform nucleus
by internal capsule
Superior surface
 Terminal
Sulcus
(superior
Thalamostriate
vein and stria
terminalis
courses here)
inferior surface




Ant.
Separated from
Hypothalamus
by hypothalamic
sulcus
post
Tegmentum of
Mesencephalon
Internal structure
Gray matter ( nueorn groups, nuclei)
 White matter ( internal and external
medullary lamina)

Internal Medullary Lamina and
External Medullary Lamina
 anterior
Nuclei of Thalamus
 medial
 Ventral
(VPM&VPL)
 dorsal
 Posterior(in
pulvinar)
 Median
 intralaminar
 reticular
Anterior nuclei
Located in the anterior
tubercle of thalamus
located ant.
thought to be related to
memory
Ventral Nuclei of Thalamus
ventral anterior
ventral lateral
ventral post.
Posteromedial
Posterolateral
Posteroinferior
Metathalamus
medial
Geniculate
body
lateral
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 ( 4142 of Brodman areas) (efferent)
Lateral Geniculate body
Relay nuclei related to vision
Afferent fibers from retina
and c superior colliculus
Efferent fibers
to Brodmann 17
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.