The document discusses the anatomy and functions of the cerebral cortex and its lobes. It begins by outlining the learning objectives which are the cerebrum, cerebral cortex, hemispheres, external features, lobes and their functions and lesions. It then describes the development of the brain and its main parts. It provides detailed information on the structure and layers of the cerebral cortex, hemispheres, lobes, their functions and common lesions. It discusses various syndromes associated with lesions in different lobes. References used are also listed.

1. CEREBRAL CORTEX
(Hemispheres & Lobes)
ASHARA T
BOT-2018

2. LEARNING OBJECTIVES
* CEREBRUM
* CEREBRAL CORTEX
*CEREBRAL HEMISPHERE
* EXTERNAL FEATURES :-
a- poles
b-surfaces
c-borders
d- sulci
* LOBES (function and lesions)

3. PARTS OF THE BRAIN

5. DEVELOPMENT OF BRAIN
FOREBRAIN
Telencephalon
Diencephalon
CEREBRUM
THALAMUS
MIDBRAIN Mesencephalon Parts of brain stem
HINDBRAIN
Metencephalon
Myelencephalon
Pons , cerebellum
Medulla oblongata

7. CEREBRUM
* Largest part of the human brain(fills the cranial cavity)
* Heavily convoluted bi lobed structure
* Situated in the Anterior & Mid cranial fossa of the skull
* Divided into 2 parts
Diencephalon (forms the central core)
Telencephalon (forms the cerebral hemisphere)

8. * Consists of two lateral halves - left and right cerebral
hemisphere
* Separated by Longitudinal cerebral fissure
* Cleft is complete – Ant & Post
* In central part –
cleft extends downward to corpus callosum (large
mass of white fibers joining 2 cerebral hemispheres)

10. Cerebral cortex
Surface layer of grey matter covering cerebral hemisphere
Surface area of cerebral cortex – 2.2 sq.m
Has many folds called gyri
grooves in b/w folds called sulci

11. LAYERS OF CEREBRAL CORTEX

13. TYPES OF CEREBRAL CORTEX
NEOCORTEX ALLOCORTEX
Phylogenetically new structure of Cerebral
cortex
Phylogenetic ally oldest structure of Cerebral
cortex
Forms the major portion 90% Forms part of limbic system
Structurally Thick & consists of 6 layers
Also called as Isocortex/Neopallium
Consists of 3 layers
Divided into Archicortex & Paleocortex

14. CEREBRAL HEMISPHERES

15. CEREBRAL HEMISPHERE
Each cerebral hemisphere consists of
a) an outer layer of grey matter cerebral cortex
b) an inner mass of white matter
c) large masses of grey matter embedded in basal part basal
ganglia/nuclei
d) A cavity within it lateral ventricle

16. CHARACTERISTIC FEATURES OF
HEMISPHERE
Right hemisphere
- Sensory stimulus and motor control from left side of the body.
-Non dominant hemisphere.
-Non verbal ideation.
-Spatial comprehension .
-Recognition of faces, places, objects.
-Creative act of arts & music.
-Context , perception.

17. Left hemisphere
- Sensory and motor control from right side of the body
-Dominant hemisphere
- Verbal ideation
-Speech
-Perception of language and comprehension
-Numerical skills
-Writing
-Recognition of words, letters, numbers

19. External features
External features of cerebral hemisphere includes
- LOBES
- POLES
- SURFACES
- BORDERS
-SULCI

20. LOBES OF CEREBRUM

21. POLES
1. Frontal Pole – Ant.end of hemisphere is more rounded & lies opposite to
superciliary arch
2. Occipital Pole – Post.end of hemisphere is more pointed & lies at short distance
to ext.occipital protuberance
3. Temporal Pole – B/w frontal & occipital poles pointed forwards & fits into
ant.part of midcranial fossa

23. SURFACES
1. Superolateral surface – most convex & extensive,faces upwards & laterally
2. Medial surface – flat & vertical, presents corpus callosum(thick C shaped cut
surface)
3. Inferior surface – irregular & divided into
- Orbital surface ( small ant.part )
- Tentorial surface ( large post.part )

25. BORDERS
1. Superomedial border
2. Superciliary border
3. Inferolateral border
4. Medial orbital border
5.Inferomedial border
6.Medial occipital border

27. SULCI
The sulci (or fissures) are the grooves and the gyri are the "bumps" that can
be seen on the surface of the brain. The folding created by the sulci and gyri
increases the amount of cerebral cortex that can fit in the skull.
1. Lateral Sulcus – b/w temporal & parietal lobe
2. Central Sulcus – b/w frontal & parietal lobe
3. Calcarine Sulcus – Caudal end of medial surface
4. Parieo-occipital Sulcus – b/w parietal & occipital

28. GYRUS
A gyrus is a ridge-like elevation found on the surface of the cerebral cortex. Gyri are surrounded
by depressions known as sulci, and together they form the iconic folded surface of the brain.

30. *Cerebral cortex is demarcated into large no.of areas Which
differ from structure as well as function .
* Brodmann (1909) divided the cerebral cortex into 52 areas &
indicated each of them by number .
TYPES
1. Motor areas ( motor function )
2. Sensory areas ( sensory function )
3. Association areas ( integrative , cognitive function)
FUNCTIONAL AREAS OF BRAIN

31. Areas 1, 2, 3 Primary somatosensory cortex (postcentral gyrus)
Area 4 Primary motor cortex (precentral gyrus)
Area 5 Somatosensory association cortex
Area 6
Area 8
Premotor and supplementary motor cortex
Area 9
Dorsolateral/anterior prefrontal cortex (motor
planning, and organization)
Area 10 Anterior prefrontal cortex (memory retrieval)
Area 17
Area 18
Primary visual cortex
Area 22 Primary auditory cortex
Area 37 Occipitotemporal (fusiform) gyrus
Areas 22, 39, 40 Wernicke's area (language comprehension)
Areas 44, 45 Broca's area (motor speech programming

33. • Lies anterior to Central sulcus & above posterior
ramus of lateral sulcus
Functions
-Initiation of voluntary movement , intelligence,
problem solving, judgement, language, conjugate
movements of eyeball.
-plays higher mental function such as motivation,
planning, social behaviour and speech production.
FRONTAL LOBE

34. • Hemiplegia :- disease or injury to the motor centers of the brain.
• Broca’s Aphasia :- “EXPRESSIVE APHASIA” characterised by partial
loss of ability to produce language although comprehension remains
intact.
• Emotional instability
• Bilateral hemiparesis
• Apraxia
• Contralateral gaze paresis:- Inability to produce conjugate eye
movements in one or both directions.
• Apathy
LESION

35. • Lies behind the central sulcus & below bounded by posterior ramus of
lateral sulcus
Functions
- Cutaneous sensation , spatial recognition (2 point discrimination,
Tactile, localization,stereognosis)
- processing of sensory information, understanding spatial orientation
and body awareness.
PARIETAL LOBE

36. • Poverty of movement
• Visuospatial disorders :- IPSILATERAL GAZE PARESIS.(complete gaze
impairment)
• Apraxia :- Inability to perform a movement or task when asked despite having the
desire and physical capability to carry it out
• Loss of tactile localization
• Anosognosia :- deficit of self awareness.
LESION

37. PARIETAL LOBE SYNDROME
*Lesion involving primarily the right (non dominant) parietal cortex.
*impaired proprioception and some degree of mental confusion
*Sensory inattention may persist indefinitely
*Anosognosia
*Hemisomatopagnosia :- denies the very existence of paretic side .

38. • Lies below the posterior ramus of lateral sulcus &
separated from the occipital lobe
Functions
- Auditory perception
The temporal lobe is involved in primary auditory
perception, such as hearing, and holds the primary
auditory cortex (area 22). The primary auditory cortex
receives sensory information from the ears and secondary
areas
( rostally in the temporal lobe and contains broadmann
area 42) process the information into meaningful units
such as speech and words.
TEMPORAL LOBE

39. • Wernicke’s aphasia ( Deafness ):- sensory aphasia
• Visual agnosia :- impairment in recognition of visually presented objects.
• Right temporal damage:- loss of inhibition of talking.
• Left temporal damage :- impaired memory for verbal material.
Auditory ,visual , gustatory & olfactory hallucination.
Dreamy states.
LESIONS

40. TEMPORAL LOBE EPILEPSY
Complaints of unpleasant smelling odors, unpleasant taste
Lost ability to speak
Sense of depersonalization
Lip smaking and chewing movement,followed by generalized
seizure.
Experience dejavu

41. • Lies behind the vertical line joining parieto-occipital
sulcus & preoccipital notch
• Functions
- Visual perception
- The occipital lobe is the visual processing area of the brain.
It is associated with visuospatial processing, distance and
depth perception, colour determination, object and face
recognition, and memory formation.
OCCIPITAL LOBE

42. * Homonymous hemianopia( contralateral/left/right)
* Visual agnosia
* Blindness partial/complete
*Loss of perception of colour
LESIONS

43. CORTICAL BLINDNESS AND
ANTON’S SYNDROME
The inability to see because of bilateral injury
to the occipital lobe .
Brains ability to process visual information.
In rare condition cortical blindness patient
insist they can see and confabulate when asked
to describe objects in the environment –
Anton’s syndrome

44. FRONTOTEMPORAL DEMENTIA
Atrophy involving predominantly the frontal and temporal
cortices (and thus different from the distribution changes in
the alzhimer’s or lewy body dementia ).
Abnormal tau proteins can be identified in nerve cells and glia.

45. GERTMANN’S SYNDROME
Area of acute infraction in the region of the left posterior
temporal and parietal region
characteristic features are finger agnosia, left right
confusion, dysgraphia , dyscalculation.

46. BALINT’S SYNDROME
It is an uncommon disorder caused by bilateral injury to parietal
and occipital
cortices
Symptoms:- optic ataxia
inability to recognize more than one object in the
visual field.
inability to change the visual fixation.
dysmetria

47. * Textbook of Clinical Neuroanatomy – Vishram Singh,3rd Edition, chapter 12-
Cerebrum, pg.no.138-151
* Adams & Victor’s Principles of Neurology – Allan Ropper, Joshua Klein 10th edition,
chapter 22- Neurological lesions, pg.no.472-478
* Gray’s clinical Neuroanatomy – Eliot L.Mancall,David G Brock,2nd edition,pg.no 279-
312
*Clinical Neuroanatomy - Richard S.Snell,7th edition,chapter 7, pg.no.252-271
*BD Chaurasia’s Brain-Neuroanatomy – Volume 4,7th edition,chapter 4, pg.no 58-73
* Essentials of Medical Physiology- Sembulingam,6th edition,Section 10 Cerebral
cortex,pg.no.884-898
REFERENCES