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THE LECTURE ON BRAIN 2013
A SHORT OVERVIEWHAMIADJI
DEVELOPMENT OF THE BRAIN
The Brain (Encephalon) includes:1. The Cerebrum that contains; - The Telencephalon (cortex, white matter and basal nuclei)2. The Diencephalon (dorsal
thalamus, hypothalamus, epithalamus, and subthalamus)
3. The Brainstem (midbrain, pons, and medulla oblongata)
4. The Cerebellum (lobes and Vermis)
THE CENTRAL NERVOUS SYSTEM
5. The Cerebellum (lobes and vermis)
Develops from the roof of the metencephalon
INTRODUCTION
The following will be discussed:1. Cerebral Cortex2. Basal ganglia (nuclei)3. Cerebral white matter
White Matter
Basal Nuclei
Cortex
I. THE LOBES OF THE CEREBRUM
III. THE MAIN CORTICAL FUNCTIONAL AREAS
Wernicke’s area = Br22 + Br39
III. THE MAIN CORTICAL FUNCTIONAL AREAS
• Primary sensory cortex --- postcentral gyrus --- Br. 1, 2, 3• Primary visual cortex --- both sides of calcarine sulcus --- Br. 17• Primary auditory cortex--- transverse gyri of Heschl --- Br. 41, 42• Olfactory cortex--- area of the uncus --- Br. 28• Motor cortex --- precentral gyrus --- Br. 4• Motor speech area (Broca’s area) --- Br. 44, 45• Frontal eyefield --- Br. 6 - 8• Auditory association cortex (Wernicke’s area) --- Br. 22, 39• Integration center --- Br. 5, 7, 40• Visual association cortex --- Br. 18, 19
Note: Lesion to the Wernicke’s area results in Receptive aphasia (alexia) Lesion to the Broca’s area results in Expressive aphasia (agraphia)
IV. THE HOMUNCULI OF PENFIELD
Representation of the body on the cerebral cortex.Motor homunculusSensory homunculus
THE HOMUNCULI OF PENFIELD
LARGE representation of a body part means many neurons are controlling that part (many small motor units) & sensory neurons
Face – many expressions &
sensationsHand – many fine
movements & sensations
V. LEFT AND RIGHT HEMISPHERES
The left hemisphere has been called the dominant or major hemisphere --- verbal and analytical abilities
The right hemisphere has been called nondominant or minor hemisphere --- nonverbal and artistic expressions
VI. THE CEREBRAL WHITE MATTER
• Association fibres – connecting areas same hemisphere• Commissural fibres – connecting areas opposite hemisphere• Projection fibres – connecting areas with spinal cord & vv.
VII. THE BASAL NUCLEI (GANGLIA)Basal ganglia in red
Diencephalon in green
VII. THE BASAL NUCLEI (GANGLIA)Basal ganglia in red
Diencephalon in green
VII. THE BASAL NUCLEI (GANGLIA)
Head of Caudate nucleusClaustrum
PutamenGlobus pallidus
Tail of Caudate nucleusAmygdala (in temporal lobe)
Lentiform nucleus
Function of Basal nuclei : Planning of motor movements
NAME THE BASAL GANGLIA (NUCLEI)
VII. THE BASAL NUCLEI (GANGLIA)
Head of Caudate nucleusClaustrum
PutamenGlobus pallidus
Tail of Caudate nucleusAmygdala (in temporal lobe) or Amygdaloid body
Lentiform nucleus
THALAMUS
PLEASE ORIENTATE YOURSELVESON THE FOLLOWING STRUCTURES
VENTRICLES
DIENCEPHALONEpithalamus
Dorsal thalamusHypothalamusSubthalamus
The Diencephalon (green) develops from
the Proscephalon and is hidden in the Cerebrum
INTRODUCTIONDIENCEPHALON
ASSOC PROF. HAMIADJI T. 24-11-2011.
2
Diencephalon
• The Diencephalon is the part of the Cerebrum that is hidden.
• The Diencephalon is the crossing point of
the cerebral cortex, pituitary gland, and the spinal cord.
3
DiencephalonOn a sagittal section of the cerebrum
the borders of the diencephalon are:• Choroid plexus of the 3rd ventricle• Habenular commissure• Epihysis (pineal body)• Posterior commissure…………. A hypothetic line ………….• Mammillary body• Tuber cinereum• Hypophysis (pituitary gland)• Optic chiasm…………. A hypothetic line ………….• Interventricular foramen (Monroe)
4
The diencephalon isdivided into 4 parts:1. Epithalamus2. Thalamus (dorsal) &
Metathalamus3. Hypothalamus4. Subthalamus
Epithalamus
Dorsal thalamus
Hypothalamus
Epithalamus forms the roof of Diencephalon & includes:•Striae medullaris thalami•Habenula & habenular commissure•Peneal body•Posterior commissure
Diencephalon 5
Thalamus• Is the largest subdivision of the
diencephalon.• Is a major integrated station that
is intercalated between many subcortical structures.
• All sensory impulses except olfaction are relayed before reaching the cerebral cortex.
• Is an ovoid structure at the side of the 3rd ventricle (small anteriorly; big posteriorly).
• Lateral surface related to the internal capsule.
• Medial surface related to 3rd ventricle.
• Superior surface related to lateral ventricles & choroid plexus (med).
• Inferior surface related to the brainstem tegmentum.
6
The thalamus consists chiefly of gray
substance.Its gray substance is
incompletely subdivided into three
parts—anterior, medial, and lateral—by
a white layer, the medial medullary
lamina.Fibres (axons &
dendrites) coming into and out are called thalamic radiation
Phylogenesis: anterior – medial (old); lateral nuclei (new)
Thalamus 7
NUCLEI OF THE THALAMUS
Basal gangliaArea6 & difuse frontal cortex
Cerebellum & Basal ganglia
Area 4
Medial lemniscus & Spinal lemniscus
Area 3,1 & 2 Trigeminothalamic tract
Area 3,1 & 2
Optic tractArea 17
Inferior colliculus &Lateral lemniscus
Area 41, 42
Areas 18, 19Inferior parietal
lobule
Mammillothalamic tract, fornix
Cingulate gyrus
Amygdaloid complex & Temporal neocortex
Prefrontal cortex
8
Structure / Nuclei
Function Destination
Anterior group Part of limbic system
Cingulum
Medial group Integrates sensory info.
Frontal lobe
Ventral group Projects sensory info.
Primary sensory cortex
Posterior group / pulvinar
Integrates sensory info.
Association areas of cortex
LGB Projects visual info. Visual cortex
MGB Projects auditory info.
Auditory cortex
NUCLEI OF THE THALAMUS 9
SubthalamusFlanks the hypothalamus laterally and thus is not
visible, is a significant subcortical station in the motor activities of voluntary muscles.
Functionally it belongs to the extrapyramidal system
Lesion results in hemiballism. An involuntary, forcefull, sudden, purposeless movement of
contra-lateral half of the body.Assoc. Prof. dr. Hamiadji T.
25.11.20011.
13
HypothalamusSeparate lecture
14
THANK YOU
THE BRAINSTEMA FIXED LEARNING MODULE
COMPILED BYAssoc Prof dr Hamiadji Tanuseputro
STUDY THEBRAINSTEM
LONGITUDINALLY
THE BRAINSTEM
Rhomboid Fossa (fossa rhomboidea; “floor” of the fourth ventricle)—The anterior part of the fourth ventricle is named, from its shape, the rhomboid fossa, and its anterior wall, formed by the back of the pons and medulla oblongata, constitutes the floor of the fourth ventricle.
DESCRIBE THE RHOMBOIDFOSSA
DEVELOPMENT OF THE BRAIN
Medulla
Pons
Midbrain
CRANIAL NERVES NUCLEI
VIII
V
XIX
IX
IV
III
VII
VI
TRY TO IDENTIFYTHE RESPECTIVE
CRANIAL NERVES.
CRANIAL NERVES NUCLEI
VII
VI
VIV
III
VIII
IX
XXI
XII
TRY TO IDENTIFYTHE RESPECTIVE
CRANIAL NERVES.
NOTESNOTES:* From the brainstem emerge cranial nerves III to XII.* The brainstem is located inferior to the Tentorium Cerebelli.* The brainstem is the site of crossing of the Cerebrum (rostrally),
the Cerebellum (dorsally) and the Spinal Cord (caudally).* The brainstem is the site of communication of the Subarachnoid
space and the Ventricular System through the foramina of Luschka & Magendie.
* The brainstem contains the Vital Centres (reticular system).
THE VENTRICULAR SYSTEM
That portion of the fluid formed in the lateral ventricles escapes by the foramen of Monro into the third ventricle and thence by the
aqueduct into the fourth ventricle. Likewise an ascending current of fluid apparently occurs in the central canal of the spinal cord; this, representing a possible product of the ependyma, may be
added to the intraventricular supply.
DESCRIBETHE CSF
CIRCULATION
THANK YOU
• A cheerful heart is good medicine, but a crushed spirit dries up the bones.
• The fear of the Lord teaches a man wisdom, and humility comes before honour.
• Many are the plans in a man’s heart, but it is the Lord’s purpose that prevails.
Assoc. Prof. dr. Hamiadji T. 25.11.2011