The document provides an overview of the cerebral cortex, detailing its anatomy, functional divisions, and specific lobes including the frontal, parietal, temporal, and occipital lobes. It discusses the roles of different areas, such as the primary motor area, Broca's area, and sensory regions, along with the consequences of frontal lobe damage. Additionally, it mentions Brodmann's areas and how brain functions are mapped across these regions.

1. CEREBRAL CORTEX

2. • INTRODUCTION
• BASIC ANATOMY
• FUNCTIONAL DIVISIONS
• FRONTAL LOBE
• PARIETAL LOBE
• TEMPORAL LOBE
• OCCIPITAL LOBE

3. GENERAL
CONSIDERATIONS
❑Highest level of CNS
❑Largest part of brain
❑Highly developed in humans

5. ❖Cerebrum - Outer gray matter and inner
white matter.
❖Outer gray matter is called CEREBRAL
CORTEX
❖ Surface of cortex is convoluted. Folds are
called as gyri and intervening grooves
are called sulci.

6. Functional part of cerebral cortex is thin layer
of neurons covering the surface of all
convolutions. It is only 2-5 mm thick. Total
cerebral cortex contains about 100 billion
neurons.

10. • Corpus callosum → bidirectional
neuronal connection between cortical
areas of 2 cerebral hemispheres
• Anterior portion of temporal lobe
including amygdala are interconnected
by fibres through anterior commissure

11. • 2 halves have independent capability for
consciousness, memory storage
communication and control of motor activities
• Corpus callosum is required for the 2 sides to
operate cooperatively at the superficial
subconscious level
• Anterior commissure plays an important role
in unifying emotional responses of 2 sides of
the brain.

12. Surfaces
1. Superolateral surface
2. Medial surface
3. Inferior surface

16. HISTOLOGY
6 LAMINAE
1) MOLECULAR / PLEXIFORM LAYER
2) EXTERNAL GRANULAR LAYER
3) OUTER PYRAMIDAL LAYER
4) INTERNAL GRANULAR LAYER
5) INNER PYRAMYDAL/ GANGLIONIC
LAYER
6) POLYMORPHOUS / MULTIFORM LAYER
16

17. 17

18. BRODMANNS AREA
• 52 Areas according to
histological
characteristics
• Korbinian Brodmann
• GERMAN NEUROLOGIST

19. BRODMANN’S AREAS

20. LOBES

21. FRONTAL POLE OCCIPITAL POLE

22. FRONTAL LOBE

23. FRONTAL LOBE
Subdivided into 2 according to function
• Precentral cortex
• Prefrontal cortex
Areas present in precentral cortex are
❖ Primary motor area [area 4]
❖ Premotor area [area 6]
❖ Supplementary motor area
❖ Frontal eye field [area 8]
❖ Broca’s area (44,45)

24. Primary motor area

25. Primary Motor
Cortex/ Precentral
Gyrus
Broca’s Area
Orbitofrontal
Cortex
Olfactory Bulb
Modified from: http://www.bioon.com/book/biology/whole/image/1/1-8.tif.jpg
Regions
Investigation (Phineas Gage)
Investigation (Phineas Gage)

26. Primary motor area
Brodmann area 4
Functions
❖ It is concerned with voluntary control of
movements produced by skeletal muscles
of the contralateral half of the body

27. ❑Topographic representation [ Motor
Homunculus]
❑ Different parts of contralateral half of
body are represented separately in more
or less inverted orders except for the face.

31. Important points
1. The representation body is contralateral &
inverted.
2. Area of representation depends upon the
functional importance and not on the size
of the part.

32. Premotor Area

34. Premotor Area
Lies on the lateral surface of each cerebral
hemisphere anterior to primary motor area. Area 6.
Functions
❖Store programs of learned motor activities of
complex and sequential nature
❖To provide postural background for performance of
complex coordinate movements.

36. Supplementary motor area

37. Supplementary motor area
Lies on the medial surface of each cerebral
hemisphere in front of primary motor cortex

39. Frontal Eye Field
Area 8
Function
Voluntary scanning movements of eye

41. Brocas speech area

42. Paul Broca (1824-1880) Carl Wernicke (1848-1905)

44. Broca’s area
Area 44,45 Motor Speech Area.
Location – Inferior Frontal Gyrus.
Functions–
• Formation of words
• It causes activation of vocal cord
simultaneously with movements of mouth &
tongue during speech.
• Lesion – expressive / Non fluent aphasia

45. Prefrontal cortex

46. Functions
• Center for planned actions
• Center for higher functions
• Short term memories are registered in prefrontal
cortex.
• Control of intellectual activities
--To prognosticate , to plan future , allows
person to concentrate in central theme of
thought
--Plays role in solution of complicated
mathematical, legal, philosophical problems.
-- It allows to control one’s activity according to
moral laws.

47. APPLIED ASPECTS
FRONTAL LOBE SYNDROME
• Symptom complex due to injury or ablation of
prefrontal cortex. Also seen in prefrontal
leucotomy and B/L prefrontal lobectomy.
• Flight of ideas– difficulty in planning.
• Emotional instability– aggressiveness &
restlessness
• Euphoria – false sense of wellbeing.
• Impairment of recent memory

48. • Loss of moral and social sense.
• Lack of attention and power of concentration
associated with restlessness.
• Lack of initiative following marked depression of
intellectual activity.
• Functional abnormalities :
--loss of control over urinary and rectal
sphincters.
--disturbances in orientation.
--slight tremor

49. PARIETAL LOBE

51. SENSORY AREAS ARE
• Somatosensory area I [area 3,1,2]
• Somatosensory area II
• Sensory association area[area 5,7 and higher
association area 40]

54. SOMATOSENSORY AREA 1
• Location: posterior to central sulcus , post
central gyrus of each parietal lobe
• Major area: Brodmann’s area 3,1,2

55. Sensory Homunculus
➢Representation of body is contralateral &
inverted.
➢ Representation of face is contralateral &
uninverted
➢Areas for lips , face and thumb are larger than
areas for trunk and leg.
➢Size of areas are directly proportional to
number of specialised sensory receptors in
each respective peripheral area of the body.

58. Somatosensory area1

59. Somatosensory area 2

61. SOMATOSENSORY ASSOCIATION AREA
• Location - Superior Parietal Lobule
• Area : Brodmann’s area 5,7.

64. Temporal lobe

65. TEMPORAL LOBE
Location – area inferior to lateral sulcus
AREAS
• Primary auditory area [area 41,42]
• Auditory association area [area 22]

66. Primary auditory area
• Location – Superior part
of temporal lobe near
lateral cerebral sulcus

67. WERNICKE’S AREA
• Superior temporal gyrus
• Brodmanns area 22

68. OCCIPITAL LOBE
Areas
• Primary visual area
• Secondary visual area
• Occipital eye field

70. PRIMARY VISUAL AREA
• Brodmann’s area 17
• Visual Perception

72. SECONDARY VISUAL AREA
• Brodmann’s areas 18,19
• Surrounds the primary visual area