The diencephalon
SHANDONG UNIVERSITY
Liu Zhiyu
I. Position

Lies between
midbrian and
cerebrum

almost entirely
surrounded by
cerebral
hemisphere
II. Subdivision
Doral thalamus
1. Dorsal thalamus
Epithalamus
2. Epithalamus
hypothalamic
sulcus
3. Hypothalamus
4. Metathalamus
5. Subthalamus
Hypothalamus
Metathalamus
Medial geniculate
body
lateral geniculate
body
Subthalamus :
transition zone between
the thalamus and
tegmentum of midbrain,
contain subthalamic
nucleus
Epithalamus :
includes
thalamic medullary stria
habenular trigone,
habenular Commissure
,
pineal body
posterior commissure
Dorsal thalamus

A large egg-shaped nucleus mass.
anterior thalamic tubercle,
pulvinar

division
anterior nuclei
medial nuclei
lateral nuclei
by internal
medullary
lamina
internal medullary lamina
Med. nuclear group
Dorsal nuclei
Ant. nuclear group
Pulvinar
Ventral anterior
nucleus
Ventral lateral
nucleus
Ventral posterolateral
nucleus
Ventral posteromedial nucleus
Ventral posterior
nucleus
Functional subdivision

According to the function, the thalamus may be
divided into the three groups
Nonspecific relay nuclei
Association nuclei
Special relay nuclei

Nonspecific relay nuclei
a) Midline nucleus group
b) Intralaminar nuclear group
c) Thalamic reticular nucleus
Receive afferent
fibers from
rhinencephalon and
reticular formation
of brain stem,
project mainly to
cerebral cortex
Intralaminar nuclei
Midline nucleus group
Thalamic
reticular
nucleus
Functional subdivision
Association
nuclei a)
Anterior nuclear group
b) Medial nuclear group
c) Dorsal nuclei of lateral nuclear group
Med. nuclear group
Dorsal nuclei
Ant. nuclear group
Special relay nuclei
Ventral anterior nucleus
Ventral lateral nucleus
receiving the fibers from：
dentate nucleus,
globus pallidus
substantia nigra
motor cortex
Ventral anterior
nucleus
Ventral lateral
nucleus

Ventral Posterior nucleus may be divided into
Ventral Posteromedial nucleus
Receives trigeminal lemniscus
teste fibers from solitory nucleus
Ventral posterolateral nucleus
receives medial lemniscus and spinal lemniscus,
trigeminal lemniscus
and teste fibers
Cerebral
cortex
medial lemniscus
spinal
lemniscus
send out fibers to the
somatosensory area
Metathalamus
Medial geniculate body (MGN)
Receive auditory fibers from brachium of inferior
colliculus
Projects to auditory area via acoustic radiation
Lateral geniculate body (LGN)
Receive fibers from optic tract .
Projects to visual area via optic
radiation .
Inferior colliculus
Optic tract
auditory area
optic radiation
visual area
Hypothalamus
Position: lies ventral to thalamus
Boundaries
1. Superiorly:
hypothalamic sulcus
2. Inferiorly:
optic chiasma,
tuber cinereum,
infundibulum
mamillary body
3. Anterior:
lamina terminalis
4. Posterior: continues
with midbrain
tegmentum
Hypothalamus
Subdivisions and important nuclei
Preoptic region
Supraoptic region
a) Supraoptic nucleus : produce antidiuretic
hormone (ADH, or vasopression)
b) Paraventricular nucleus: produce oxytocin。
Tuberal region
Infundibular nucleus
Mamillary region
Mamillary nucleus
Connects
with hypophysis 垂体
Paraventricular nucleus
Supraoptic nucleus
(vasopressin )
Paraventriculohypophyseal tract
Supraopticohypophyseal
tract
(oxytocin )
posterior lobe of hypophysis
Connects
with hypophysis 垂体
Tuberoinfundibular tract
Function
Regulates the function of
neuroendocrine system
and autonomic nervous
System.
Infundibular nucleus
Median eminence
Portal v.
anterior lobe
Hypophyseal v.
Third ventricle
Position:
a narrow cleft lies within diencephalon.
Interventricular
foramen

Communication
1.
By the Interventricular
foramen → lateral
ventricle
2.
by mesencephalic
aqueduct → fourth
ventricle
mesencephalic
aqueduct
Lateral geniculate body
Medial geniculate body
Metathalamus
Paraventricular nucleus
Paraventriculohypophyseal
tract
Supraoptic nucleus
Supraopticohypophyseal
trac
Mamillary nucleus
arcuate nucleus
tuberoinfundibular tract
infundibulum
anterior lobe
of hypophsis
posterior lobe
of hypophysis
habenular trigone
Pineal body
habenular Commissure
Hypothalamus --connection



Connects with limbic system
Connects with brainstem and spinal cord
Connects with dorsal thalamus
Connects with hypophysis
a) Supraoptic nucleus (vasopressin)
→supraopticohypophyseal trac →posterior lobe of
hypophysis
b) Paraventicular nucleus (oxytocin)
→paraventriculohypophyseal tract→posterior lobe of
hypophysis
c) Parvicellular neurons in the arcuate nucleus and nearby
region of the walls of the third ventricle secrete releasing
and inhibiting hormones → tuberoinfundibular tract
→portal vein of hypophsis → anterior lobe of hypophsis

Subdivision
Principal Nuclei
Common
abbreviation
Ant. nuclear group
Med. nuclear group
Lat. nuclear group
Dorsal group
Lateral dorsal
LD
Lateral posterior
LP
Pulvinar
Ventral group
Ventral anterior
VA
Ventral intermediate
VI
Ventral posterior
VP
Ventral posterolateral
VPL
Ventral posteromedial
VPM
Third ventricle
Position:
a narrow cleft lies within diencephalon.
Boundaries
Roof: choroids plexus
Floor: from ant. To post.
optic chiasma
tuber cinereum,
infundibulum
mamillary body。
Anterior: lamina terminalis
Posterior: continuous with
mesencephalic aqueduct
Lateral wall: dorsal thalamus and
hypothalamus
Communication
a. Interventricular foramen →lateral ventricle
b.Third ventricle → mesencephalic aqueduct
→ fourth ventricle
Interventricular foramen
Tectum of
midbrain
Tegmentum
of midbrain
Cerebral
peduncle
Substantia
nigra
Crus
cerebri