function of thalamus thalamus and hypothalamus hypothalamus function thalamus in flower thalamus location thalamus memory

1. THALAMUS

5. Subdivisions of cerebrum:

6. CEREBRUM
 DIENCEPHALON:FORMS CENTRAL CORE
THALAMUS
HYPOTHALAMUS
SUBTHALAMUS(red
nucleus,substantia nigra)
EPITHALAMUS(hebanulear
nucleus,pineal gland)
 TELENCEPHALON:CEREBRAL HEMISPHERES

7. Diencephalon
• BOUNDARIES
• Anteriorly: up to interventricular foramen
• Posteriorly: 3rd ventricle become continuous with
cerebral aqueduct

11. BOUNDARIES:
• INFERIORLY: Optic chiasma with Optic Tract on either
sides, Infundibulum with Tuber Cinereum , and the
Mammillary Bodies
• SUPERIORLY: concealed by FORNIX. Actual superior
surface is formed by ROOF OF 3RD VENTRICLE.
(consisting of ependymal lining of 3rd ventricle,
Telachoroidea of 3rd ventricle, choroid plexus of 3rd
ventricle)

18. BOUNDARIES
• LATERAL SURFACE : Internal capsule
• MEDIAL SURFACE : formed by Medial Surface of
THALAMUS, HYPOTHALAMUS, STRIA MEDULLARIS
THALAMI, INTERTHALAMIC ADHESIONS
• Stria Medullaris Thalami: Bundles of nerve fibers which
are afferent to HABENULAR NUCLEUS form a ridge
along the SUPERIOR margin of MEDIAL surface of
Diencephalon

23. THALAMUS
 LARGE EGG SHAPED
GRAY MATTER
 TWO IN NUMBER
 ONE ON EACH SIDE
OF DIENCEPHALON

24. THALAMUS
 Cell Station to all main sensory systems(except
OLFACTORY PATHWAY)
 FOR INFORMATION GOING TO CORTEX,BASAL
GANGLIA,BRAINSTEM AND HYPOTHALAMUS.
 MAIN PART OF DIENCEPHALON

27. THALAMUS
• Anterior end – narrow and rounded
• Posterior end – expanded to form PULVINAR, Overhangs
superior colliculus
• Superior Surface —Medially; tela choroidea & fornix
laterally; ependymal& floor of lateral ventricle
Inferior Surface--- continuous with TEGMENTUM of midbrain
Medial Surface--- superior part of lateral wall of 3rd ventricle,
connected to oppsite thalamus by INTERTHALAMIC CONNECTION
Lateral Surface--- internal capsule

30. SUBDIVISIONS OF THALAMUS
 COVERED BY THIN LAYER OF WHITE
MATTER….STRATUM ZONALE
 ON ITS LATERAL SURFACE IT IS COVERED BY
ANOTHER LAYER CALLED EXTERNAL
MEDULLARY LAMINA
 INTERNAL MEDULLARY LAMINA(CONSIST
OF NERVE FIERS THAT PASS FROM ONE
THALAMUS TO ANOTHER) DIVIDES WHITE
MATTER INTO MEDIAL AND LATERAL HALVES

31. SUBDIVISIONS OF THALAMUS
 ANTERIOR PART:
ANTERIOR THALAMIC
NUCLEI
 MEDIAL PART :
DORSOMEDIAL
NUCLEUS
 LATERAL PART:
DORSAL TIER OF
NUCLEUS
VENTRAL TIER OF
NUCLEUS

32. DORSAL TIER OF NUCLEI
 LATERAL DORSAL NUCLEUS
 LATERAL POSTERIOR NUCLEUS
 PULVINAR

33. VENTRAL TIER OF NUCLEI
 VENTRAL ANTERIOR NUCLEUS
 VENTRAL LATERAL NUCLEUS
 VENTRAL POSTERIOR
NUCLEUS:(POSTEROMEDIAL AND
POSTEROLATERAL)

34. OTHER NUCLEI OF THALAMUS
 INTRALAMINAR NUCLEI
 MIDLINE NUCLEI
 RETICULAR NUCLEI
 MEDIAL GENICULATE BODY
 LATERAL GENICULATE BODY

36. CONNECTIONS OF THALAMUS
 EVERY THALAMIC NUCLEI (EXCEPT RETICULAR
NUCLEUS)SENDS AXONS TO SPECIFIC PARTS OF
CEREBRAL CORTEX AND RECIVES RECIPROCAL
FIBERS FROM CORTEX
 RELAY STATION FOR:
1:CEREBELLAR-RUBRO-THALAMIC-CORTICAL-
PONTO-CEREBELLAR LOOP
2:CORTICALSTRIATAL-PALLIDAL-THALAMIC-
CORTICAL LOOP

37. VARIOUS THALAMIC NUCLEI,THEIR NERVOUS CONNECTIONS,AND
THEIR FUNCTIONS
THALAMIC NUCLEUS AFFERENT
NEURONAL LOOP
EFFERENT
NEURONAL LOOP
FUNCTION
Anterior Mamillothalamic tract Cingulate gyrus,
hypothalamus
Emotional
tone,mechanism of recent
memory
Dorsomedial Prefrontal
cortex,hypothalamus,othe
r thalamic nuclei
Prefrontal
cortex,hypothalamus,othe
r thalamic nuclei
Integration of
somatic,visceral and
olfactory information and
relation to emotional
feelings and subjective
states
Lateral dorsal,lateral
posterior,pulvinar
Cerebral cortex,other
thalamic nuclei
Central cortex,other
thalamic nuclei
unknown
Ventral anterior Reticular
formation,substantia
nigra,corpus
striatum,premotor
cortex,other thalamic
nuclei
Same as afferents Influences motor activity
of motor cortex
Ventral lateral Same as ventral ant.plus
major inputs from
cerebellum and minor
input from red nucleus
Same as afferents Same as above
Ventral posteromedial Trigemminal
nucleus,gustatory fibers
Primary somatic sensory
(3,1,2) cortex.

38. Various thalamic nuclei and their connections
Thalamic nucleus Afferent neuronal loop Efferent neuronal loop funtion
VPM TRIGEMMLINAL
NUCLEUS,GUSTATORY
FIBERS
AREA3,1,2 RELAYS COMMON
SENSATIONS TO
CONSCIOUSNESS
VPL MEDIAL AND SPINAL
LEMINISCI
AREA3,1,2 SAME AS ABOVE
INTRALAMINAR RETICULAR
FORMATION.SPINOTHAL
AMIC AND
TRIGEMMINOTHALAMIC
TO CEREBRAL
CORTEX,OTHER
THALAMIC
NUCLEI,CORPUS
STRIATUM
INFLUENCES LEVEL OF
CONSCIOUSNESS AND
ALERTNESS
MIDLINE RETICULAR FORMATION UNKNOWN UNKNOWN
RETICULAR CEREBRAL
CORTEX,RETICULAR
FORMATION
OTHER THALAMIC
NUCLEI
?CEREBRAL
CORTEX,REGULATES
THALAMUS
MEDIAL GENICULATE
BODY
INFERIOR
COLLICULUS,LATERAL
LEMINISUS,FROM BOTH
EARS PREDOMINANTLY
FROM CONTRALATERAL
EAR
AUDITORY RADIATION TO
SUPERIOR TEMPORAL
GYRUS
HEARING
LATERAL GENICULATE
BODY
OPTIC TRACT OPTIC RADIATION TO
VISUAL CORTEX
VISUAL INFO FROM
OPPOSITE FIELD OF
VISION

39. Functions of thalamus
 Consists of complicated connections of nerve cells that
are interconnected
 Vast amount of sensory information converges on
thalamus
 Anatomically and functionally thalamus and cerebral
cortex are closely linked,removal of cortex causes
thalamus to appreciate crude sensations
 VPL,APM ,LATERAL GENICULATE AND MEDIAL
GENICULATE BODY ARE important nuclei
 Venteroanterior and venterolateral nuclei form part of
basal nuclei and are involved in performance of
voluntary movements

40.  Dorsomedial nucleus has extensive connections with
frontal lobe cortex and hypothalamus
 Intralaminar nuclei are closely connected with
activities of reticular formation.

41. Clinical significance
 Lesion of thalamus
 Sensory loss
 Surgical relief of pain by thalamic cauterization
 Thalamic pain
 Abnormal involuntary movements