Thalamus anatomy

2. Dr. Talha- Sami- Ul- Haque
Honorary Medical Officer
Dept. of Neurology
Dhaka Medical College Hospital

3. • Introduction
• Development
• Anatomical Arrangement
• Connections
• Blood supply
• Function
• Summary

5. situated between the cerebral cortex and
midbrain.
Thalamus is a large egg shaped mass of grey matterThalamus (from the Greek word "inner chamber")A midline symmetrical structure within the brains of
vertebrates including humans.
Thalamus is located on each side of third ventricle.From it, nerve fibers projecting out to the cerebral cortex in all directions.

7. Coronal Section

8. • The thalamus is the largest structure
deriving from the
embryonic diencephalon, the posterior
part of the forebrain situated between
the midbrain and the cerebrum.
• The thalamic complex is composed of
the perithalamus/ prethalamus, the
mid-diencephalic organiser and the
thalamus (dorsal thalamus).

9. • Two transcription factors, Fez and Otx
are required for proper development of
the thalamus

11. Narrow
forms the posterior
end of the
interventriculer
foramina.
Anterior:

12.  Expanded to form the
pulvinar.
 which overhangs the
superior colliculus.
Posterior:

13.  covered medially by the
tela choroidea and
fornix
 laterally it is covered by
ependyma and forms
the part of the floor of
the lateral ventricle.
Superior:

14.  Continuous with the
tegmentum of the
midbrain
Inferior:

15.  Forms part of the lateral wall
of the third ventricle
 Connected to the opposite
side by a band of grey matter
called interthalamic
connection.
Medial:

16.  Separated from the
lentiform nucleus by the
band of white matter
called internal capsule.
Lateral:

18. Sub division of the Thalamus
 Anterior part
 Middle part
 Lateral part
Subdivided into three main parts.

20. Nucleus of Thalamus

22. Thalamic nuclei and their connections and
functions
Thalamic
Nucleus
Afferent connections
Efferent
connections
Functions
Anterior
Mammillothalamic tract,
singulate gyrus,
hypothalamus
singulate gyrus,
hypothalamus
Emotional tone,
mechanism of
recent memory
Dorsomedial
Prefrontal cortex,
hypothalamus, other
thalamic nuclei
Prefrontal cortex,
hypothalamus,
other thalamic
nuclei
Integration of
somatic visceral
and olfactory
information and
relation to
emotional feelings
and subjective
stage
Lateral
dorsal,
lateral
posterior,
pulvinar
Cerebral cortex, other
thalamic nuclei
Cerebral cortex,
other thalamic
nuclei
Unknown

23. Thalamic nuclei and their connections and
functions
Thalamic
Nucleus
Afferent connections
Efferent
connections
Functions
Ventral
anterior
Reticular formation,
substantia naigra, corpus
striatum, Prefrontal cortex,
other thalamic nuclei
Reticular formation,
substantia naigra,
corpus striatum,
Prefrontal cortex,
other thalamic
nuclei
Influences activity of
motor cortex
Ventral
lateral
As in ventral anterior
nucleus also from
cerebellum and red
nucleus
As in ventral
anterior nucleus
also from
cerebellum and red
nucleus
Influences activity of
motor cortex
Ventral
postero
medial
Trigeminal lamniscus,
gustatory fibers
Primary somatic
sensory cortex
(Area 3,1,2)
Relays common
sensation to
consciousness
Ventral
postero
lateral
Medial and spinal lemnisci
Primary somatic
sensory cortex
(Area 3,1,2)
Relays common
sensation to
consciousness

24. Thalamic nuclei and their connections and
functions
Thalamic
Nucleus
Afferent connections
Efferent
connections
Functions
Intra
lamminar
Reticular formation,
spino-thalamic and
trigemino thalamic tract
Cerebral cortex
via other thalamic
nuclei, corpus
striatum
Influences
level
consciousness
and alertness
Midline Reticular formation Unknown Unknown
Reticular
cerebral cortex, reticular
formation
Other thalamic
nuclei
? regulates
thalamus

25. Thalamic nuclei and their connections
and functions
Thalamic
Nucleus
Afferent
connections
Efferent
connections
Functions
Medial
geniculate
body
Inferior colliculus,
lateral lemniscus from
both ears but
predominantly contra
lateral ears
Auditory
radiation to
superior
temporal gyrus
Hearing
Lateral
geniculate
body
Optic tract
Optic radiation,
visual cortex of
occipital lobe
Visual
information from
opposite field of
vision

27. From four arteries
• The polar artery
(posterior
communicating
artery),
• Paramedian thalamic-
subthalamic arteries,
• Inferolateral
(thalamogeniculate)
arteries and
• Posterior (medial and
lateral) choroidal
arteries.

29. 1. Thalamus is an important relay and integrative center.
2. A vast amount of sensory information of all types except
smell converge to the thalamus and integrated through
the interconnections between the nuclei. The resulting
information pattern is distributed to other part of the
CNS.
3. Anatomically and functionally the thalamus and the
cerebral cortex are closely linked. The thalamus can
appreciate crude sensation even after the removal of the
cortex.

30. 4. It is concerned with subjective feeling state and the
personality of the individual.
5. The intra laminar nuclei are able to influence the level
of conciseness and alertness in an individual.
6. The thalamus also plays an important role in regulating
states of sleep and wakefulness.
7. Many of the sensory systems (except for the olfactory
system), such as
the auditory, somatic, visceral, gustatory and visual
systems where localized lesions provoke specific sensory
deficits.

32.  Every thalamic nucleus (except reticular nucleus)
sends axons to specific parts of cerebral cortex and
every part of cerebral cortex sends reciprocal fibres
back to the thalamic nuclei. This would indicate that
information received by the thalamus is always
shared with the cerebral cortex and that the cortex
and the thalamus can modify each other’s activities.

33.  The thalamus is an important relay station for two
sensory-motor axonal loops involving the cerebellum
and the basal nuclei
 The cerebellar-rubro-thalamic-cortical-ponto-cerebellar
loop
 The corticalstriatal-pallidal-thalamic-cortical loop
Both are necessary for normal voluntary movement.