Anatomy of thalamus

1. By
Dr Manah Chandra Changmai

2. Thalamus is a part of diencephalon
Diecephalon divided into 4 regions
Thalamus
Hypothalamus
Epithalamus
Ventral thalamus(or subthalamus)

3. Diencephalon

5. Thalamus

6. Thalamus
Large mass of grey matter,lies immediately
lateral to third ventricle
The thalamus is an ovoid nuclear mass, c.4cm
long, which borders the dorsal part of third
ventricle
Two poles
Anterior pole(or end)
-Lies behind the interventricular foramen
Posterior pole(or end)
-Also called PULVINAR
-Lies just above and lateral to superior
colliculus.
Thalamus

7. Anterior pole
Posterior
pole or
pulvinar
Thalamus
Superior
colliculus
Interventricular
foramina
Thalamus

8. Superior(dorsal) surface
-The superior (dorsal) surface of the thalamus
is covered by a thin layer of white matter, the
stratum zonale
-It extends laterally from the line of reflection
of the ependyma (taenia thalami), and forms
the roof of the third ventricle
-This curved surface is separated from the
overlying body of the fornix by the choroid
fissure with the tela choroidea within it.
-More laterally it forms part of the floor of the
lateral ventricle.
-related laterally to caudate nucleus
-Seperated from caudate nucleus stria
terminalis and thalamostriate vein.
Superior surface

9. Superior surface
Inferior surface
Medial surface
Surfaces of the thalamus

10. The medial surface of the thalamus is the
superior (dorsal) part of the lateral wall of the
third ventricle.
It is usually connected to the contralateral
thalamus by an interthalamic adhesion behind
the interventricular foramina.
The boundary with the hypothalamus is
marked by an indistinct hypothalamic sulcus,
which curves from the upper end of the
cerebral aqueduct to the interventricular
foramen.
The thalamus is continuous with the midbrain
tegmentum, the subthalamus and the
hypothalamus
Medial surface
The medial surface

11. Medial surface of thalamus
Hypothalamus
Midbrain tegmentum

12. Inferior surface of the tegmentum is related
to hypothalamus anteriorly and to ventral
thalamus posteriorly.
The ventral thalamus seperates the thalamus
from tegmentum of midbrain
Inferior surface of thalamus

13. Internally, the thalamus is divided into anterior, medial and lateral
nuclear groups by a vertical Y-shaped sheet of white matter, the
internal medullary lamina
Nuclei of the anterior part.
Anterior nucleus.
Nuclei in the medial part
Largest nuclei among them medial dorsal nucleus.
Internal structure of the thalamus
Thalamus consists of mainly of grey matter
Superior surface is covered by a thin layer of
white matter called stratum zonale
Lateral surface is covered by a similar layer called external
medullary layer.

14. Nuclei in the lateral part
Ventral group Lateral group
Ventral anterior nucleus
Ventral lateral nucleus
Or
Ventral intermediate nucleus
Ventral posterior nucleus
Lateral dorsal
nucleus
Lateral posterior
nucleus
Pulvinar

15. Other thalamic nuclei
Intralaminar nuclei
Embedded within the internal medullary
Lamina
Midline nuclei
Scattered cells between medial part of the
thalamus and ependyma of third ventricle.
Medial and lateral geniculate bodies
Now included under the thalamus.

18. Connections of the thalamus
Afferent impulses from large number of
Subcortical centres converge to the thalamus.
Visual and aduditory impulses reach the lateral
And medial geniculate bodies.
Sensation of taste are conveyed to the thalamus
Through solitariothalamic fibres
Thalamus does not receive direct olfactory impulses
They probably reach through amygdaloid complex.
Thalamus receive profuse connections from all part
Of cerebral cortex,cerebellum and corpus striatum.

19. Thalamus is there fore regarded as integrating centre
Where information of all sources is brought together.
The information from thalamus is projected to whole
Of the cerebral cortex through thalamo-cortical projection.
Thalamocortical fibres form large bundles known as
Thalamic radiations or thalamic radiation.
Thalamic radiations
Superior thalamic radiation
(dorsal )
Posterior thalamic radiations
( caudal )
Ventral thalamic
radiation

20. Anterior
thalamic
radiations
Superior thalamic radiations
Posterior thalamic radiation
Thalamus

21. Connection of ventral group of nuclei
Most important connection of thalamus are from ventral posterior
nucleus
cerebral cortex
(somatosensory area,3 1 2)
ventral posterior nucleus
medial part lateral part
Trigeminothalamic tract
Solitariothalamic tract
Medial leminiscus
Spinothalamic tract

22. cerebral cortex
premotor and
supplementary motor area
Area 4
ventral lateral nucleus
Anterior part Medial part Posterior part
From globus
pallidus
From substantia
nigra
From
Cerebellar nuclei
Vestibular nuclei
Spinal cord
Ventral lateral nucleus

23. cerebral cortex
Gyrus
cinguli
Parahippo
campal
gyrus
Parietal
lobe
Prefrontal
& orbito
frontal
Temporal Occipita
l lobe
Lateral
dorsal
Lateral posterior pulvinar
Superior colliculus
& Pretectal area
Retina
Connection of lateral group of nucleuses

25. Medial and lateral geniculate bodies are oval
Collection of grey matter
Situated below the posterior part of thalamus.
Traditionally under metathalamus,functionally
Under thalamus.
The medial geniculate bodies
-Relay station of the auditory pathway.
-Medial geniculate body recieves fibres of lateral
leminiscus.
-Fibres arising in the medial geniculate bodies
constitute the acoustic radiation.
Medial geniculate body

26. Acoustic area
of cerebral
cortex
Medial
geniculate
body
pulvinar
Inferior
colliculus
Superior
olivary
nucleus
Opposite
superior
olivary
nucleus
Inferior brachium
Lateral leminiscus
Connection of medial geniculate body

27. Lateral geniculate body
Relay station for visual pathway
 Recieves fibres from retinae of both the eyes
Efferent fibres arising in the body constitute
optic radiation.
 Sections through lateral geniculate body shows
partially split six lamellae seperated by nerve
fibres.
Lateral geniculate body also recieves fibres from
primary visual cortex.,superior colliculus,and
from the reticular formation of pons and medulla.
Lateral geniculate body

28. Lateral geniculate
body
Raphe
nuclei
Locus
coeruleus
Other areas in
pons & medulla
Reticular formation
Pulvinar
Retina
Ipsilateral &
Contralateral
Visual areas of
cerebral
cortex
Superior
colliculus
Connections of lateral geniculate body

29. Blood supply of thalamus
Perforating branches of the posterior cerebral artery
Posteromedial group(thalamo-perforating arteries) supply
medial and anterior part.
Posterolateral group ( thalamo-geniculate branches) supply
posterior and lateral part of thalamus.
Also recieves branches from posterior communicating
anterior choroidal,posterior choroidal and middle cerebral
artery.

30. Thalamic syndrome
Thalamic syndrome (or thalamic pain syndrome) is a condition that
can be associated with inadequate blood supply from the
posterior cerebral artery.
Rare neurological disorder in which the body becomes
hypersensitive to pain as a result of damage to the thalamus, a part
of the brain that affects sensation
Primary symptoms are pain and loss of sensation, usually in the
face, arms, and/or legs.
Pain or discomfort may be felt
[1]
after being mildly touched or even
in the absence of a stimulus.
The pain associated with thalamic syndrome may be made worse by
exposure to heat or cold and by emotional distress. Sometimes, this may
include even such emotions as those brought on by listening to music.
It is also known as "Dejerine-Roussy disease", after
Joseph Jules Dejerine and Gustave Roussy

31. Thankyou