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Lecture by
Dr.N.Mugunthan.MBBS.,MS.,DNB.,MNAMS.,PhD.,MBA (Hosp.Adm.).,
Associate Professor
MGMC&RI
Learning objectives
1. Sulci
2. Gyri
3. Functional areas
a) Motor areas
b) Sensory areas
c) Psychical areas
4. Effects of ...
Cerebrum
Presenting parts:
Each cerebral hemisphere has
• 3 poles
• 3 surfaces
• 3 borders
• 6 lobes
©Dr.N.Mugunthan
3 poles:
1. Frontal pole
2. Occipital pole
3. Temporal pole
(primitive post.pole)
Cerebrum cont…
FP
OPTP
©Dr.N.Mugunthan
3 surfaces:
1. Superolateral surface
2. Medial surface
3. Inferior surface
a) Orbital surface
b) Tentorial surface
Cerebru...
3 borders:
1. Superomedial border
2. Inferolateral border (ant.1/3
- superciliary border)
3. Inferomedial border
(ant.1/3-...
6 lobes:
1. Frontal lobe
2. Parietal lobe
3. Temporal lobe
4. Occipital lobe
5. Insular lobe (Island of
Reil)[sperolateral...
Sulci & Gyri
Main cerebral sulci:
1. Lateral sulcus (Sylvius)
• Stem & 3 rami
(posterior, ascending
& anterior)
2. Central...
Frontal lobe:
• Precentral sulcus
• Precentral gyrus
• Superior frontal sulci &
• Inferior frontal sulci
• Superior fronta...
• Anterior & ascending
rami of lateral sulcus
divides the inf.frontal
gyri into 3 areas
a) Pars orbitalis
b) Pars triangul...
Parietal lobe:
• Postcentral sulcus
• Postcentral gyrus
• Intraparietal sulcus
• Superior parietal lobule
• Inferior parie...
• The upturned ends of
post.ramus of lateral
sulcus, sup. & inf.
temp.sulcus extends into
inf.parietal lobule and
divides ...
Temporal lobe:
• Superior temporal sulci &
• Inferior temporal sulci
• Superior temporal gyrus
• Middle temporal gyrus
• I...
Occipital lobe:
• Lateral occipital sulcus
• Superior & inferior
occipital gyrus
• Lunate sulcus
• Calcarine sulcus
Sulci ...
©Dr.N.Mugunthan
Sulci & Gyri on the medial surface
• Callosal sulcus
• Cingulate sulcus
• Cingulate gyrus
• Medial frontal gyrus
• Paracen...
• Suprasplenial sulcus
• Parieto-occipital sulcus
• Calcarine sulcus
• Cuneus
• Precuneus
Isthmus –narrow region
between ...
Orbital part:
• Olfactory sulcus
• Gyrus rectus
• Orbital sulcus (H-shaped)
• Medial orbital gyrus
• Lateral orbital gyrus...
Tentorial part:
• Collateral sulcus (medial)
• Occipito-temporal sulcus
(lateral)
• Medial occipito-temporal
gyrus
• Later...
Broadmann mapping
52 areas in cerebral
cortex
©Dr.N.Mugunthan
Types of cortical functional areas
3 Types of functional
areas
1. Motor areas
2. Sensory areas
3. Association areas
©Dr.N...
Primary motor area (area 4)
 Precentral gyrus
(superolateral surface)
 Motor homunculus
 Control voluntary
movements of...
Effects of lesion – primary motor area
Contralateral Flaccid
paralysis –initially
↓DTR
+Ve Babinski sign
Moderate recovery...
Pre-motor area (area 6 & 8)
Area 6- skillful acts
(programming of
movements)
Upper part of area 6 –
writing centre
 Area ...
Supplementary motor area
 Continuation of area 6 on
medial surface
Function:
 control complex
movements
 Elicits an urg...
Pre-frontal area (areas 9 to 12)
 In front of premotor area
 Highly developed in
human
Functions:
 Regulates the depth ...
Sensory areas
1. Primary sensory area
2. Secondary sensory area
(only for somesthetic
senses)
3. Sensory association area
...
Primary sensory area
1. Somesthetic area
2. Visual area
3. Auditory area
©Dr.N.Mugunthan
Somesthetic area
Primary somesthetic area (area 3,1,2)
 Located in post central gyrus
(superolateral surface)
 Functions...
Paracentral lobule –
receives sense of
distension of bladder &
rectum
Primary somesthetic area – functions cont…
©Dr.N.Mug...
Secondary somesthetic area
(supplementary)
Upper lip of posterior
ramus of lateral sulcus
(lower part of pre & post
centra...
Somesthetic association area (area 5,7)
Behind the post
central gyrus
(superior parietal
lobule – area 5,7)
©Dr.N.Mugunthan
Higher association area for somesthetic senses
(area 40)
Supramarginal gyrus
(area 40)
Richly connected with
area 5 & 7
Le...
Visual senses
1. Primary visual area
(area17)
2. Visual association area
(area 18 & 19)
3. Higher visual association
area ...
Visual association area (area 18 &19)
Parastriate area (area
18)/ visual area-II and
Peristriate
area(area19)/visual area-...
Auditory senses
1. Primary auditory area
(area 41)
2. Auditory association area
(area42)
3. Higher auditory
association ar...
Psychical cortex
Anterior part of temporal
lobe(temporal pole)
Function :
Memory (present & past)
Dreams
Hallucination (au...
 Performed by left
cerebral hemisphere
(regardless of hand
preference)
 Hence left hemisphere-
dominant or talking brain...
Dominant hemisphere has 4
speech centres (3 sensory &
1 motor centre)
Sensory speech area:
1. Area 22
(higher auditory as...
Motor speech centre:
4. Area 44 & 45 (Broca’s
area)
Speech centres (motor &
sensory) may be
transferred to right
hemispher...
Area 22,39,40 – receives
input from hearing,vision
,touch &proprioception
Information processed in
area 22 (post.part)
Pro...
Lesions of speech centre
 Lesion involving speech
centre (dominant
hemisphere) – aphasia
2 types:
1. Sensory aphasia
2. M...
Main cerebral sulci:
1. Lateral sulcus (Sylvius)
• Stem & 3 rami
(posterior, ascending
& anterior)
2. Central sulcus
(Rola...
Summary
Functional areas :-
1. Motor areas
2. Sensory areas
3. Psychical areas
©Dr.N.Mugunthan
Motor areas :-
1. Primary motor area
2. Pre-motor area
3. Supplementary motor
area
4. Pre-frontal area
Summary cont…
©Dr.N...
Summary cont…
Sensory areas:-
1. Primary sensory area
2. Secondary sensory
area (only for
somesthetic senses)
3. Sensory a...
Summary cont…
Primary sensory areas:-
1. Somesthetic area
2. Visual area
3. Auditory area
©Dr.N.Mugunthan
Sulci,Gyri & Functional areas of cerebrum Dr.N.Mugunthan.M.S
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Sulci,Gyri & Functional areas of cerebrum Dr.N.Mugunthan.M.S

Sulci,Gyri & Functional areas of cerebrum -PDF Lecture notes by Dr.N.Mugunthan.M.S

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Sulci,Gyri & Functional areas of cerebrum Dr.N.Mugunthan.M.S

  1. 1. Lecture by Dr.N.Mugunthan.MBBS.,MS.,DNB.,MNAMS.,PhD.,MBA (Hosp.Adm.)., Associate Professor MGMC&RI
  2. 2. Learning objectives 1. Sulci 2. Gyri 3. Functional areas a) Motor areas b) Sensory areas c) Psychical areas 4. Effects of lesions of functional areas ©Dr.N.Mugunthan
  3. 3. Cerebrum Presenting parts: Each cerebral hemisphere has • 3 poles • 3 surfaces • 3 borders • 6 lobes ©Dr.N.Mugunthan
  4. 4. 3 poles: 1. Frontal pole 2. Occipital pole 3. Temporal pole (primitive post.pole) Cerebrum cont… FP OPTP ©Dr.N.Mugunthan
  5. 5. 3 surfaces: 1. Superolateral surface 2. Medial surface 3. Inferior surface a) Orbital surface b) Tentorial surface Cerebrum cont… ©Dr.N.Mugunthan
  6. 6. 3 borders: 1. Superomedial border 2. Inferolateral border (ant.1/3 - superciliary border) 3. Inferomedial border (ant.1/3-medial orbital border, middle 1/3 - hippocampal border, post 1/3 – medial occipital border) Cerebrum cont… ©Dr.N.Mugunthan
  7. 7. 6 lobes: 1. Frontal lobe 2. Parietal lobe 3. Temporal lobe 4. Occipital lobe 5. Insular lobe (Island of Reil)[sperolateral surface] 6. Limbic lobe [medial surface] Cerebrum cont… ©Dr.N.Mugunthan
  8. 8. Sulci & Gyri Main cerebral sulci: 1. Lateral sulcus (Sylvius) • Stem & 3 rami (posterior, ascending & anterior) 2. Central sulcus (Rolando) 3. Parieto-occipital sulcus 4. Calcarine sulcus ©Dr.N.Mugunthan
  9. 9. Frontal lobe: • Precentral sulcus • Precentral gyrus • Superior frontal sulci & • Inferior frontal sulci • Superior frontal gyrus • Middle frontal gyrus • Inferior frontal gyrus Sulci & Gyri on superolateral surface ©Dr.N.Mugunthan
  10. 10. • Anterior & ascending rami of lateral sulcus divides the inf.frontal gyri into 3 areas a) Pars orbitalis b) Pars triangularis c) Pars opercularis Sulci & Gyri on superolateral surface cont… ©Dr.N.Mugunthan
  11. 11. Parietal lobe: • Postcentral sulcus • Postcentral gyrus • Intraparietal sulcus • Superior parietal lobule • Inferior parietal lobule Sulci & Gyri on superolateral surface cont… ©Dr.N.Mugunthan
  12. 12. • The upturned ends of post.ramus of lateral sulcus, sup. & inf. temp.sulcus extends into inf.parietal lobule and divides it into 3 parts a) Supramarginal gyrus b) Angular gyrus c) Arcus temporo- occipitalis Sulci & Gyri on superolateral surface cont… ©Dr.N.Mugunthan
  13. 13. Temporal lobe: • Superior temporal sulci & • Inferior temporal sulci • Superior temporal gyrus • Middle temporal gyrus • Inferior temporal gyrus • Sup. surface of sup.temporal gyrus has • 2 transverse temporal gyrus (ant. & post.) • Ant.transverse temporal gyrus (Heschl’s gyrus – primary auditory area) Sulci & Gyri on superolateral surface cont… ©Dr.N.Mugunthan
  14. 14. Occipital lobe: • Lateral occipital sulcus • Superior & inferior occipital gyrus • Lunate sulcus • Calcarine sulcus Sulci & Gyri on superolateral surface cont… ©Dr.N.Mugunthan
  15. 15. ©Dr.N.Mugunthan
  16. 16. Sulci & Gyri on the medial surface • Callosal sulcus • Cingulate sulcus • Cingulate gyrus • Medial frontal gyrus • Paracentral lobule (higher centre for micturition & defecation) • Ant.& post. parolfactory sulcus • Paraterminal gyrus • Parolfactory gyrus ©Dr.N.Mugunthan
  17. 17. • Suprasplenial sulcus • Parieto-occipital sulcus • Calcarine sulcus • Cuneus • Precuneus Isthmus –narrow region between splenium & calcarine sulcus Sulci & Gyri on the medial surface cont… ©Dr.N.Mugunthan
  18. 18. Orbital part: • Olfactory sulcus • Gyrus rectus • Orbital sulcus (H-shaped) • Medial orbital gyrus • Lateral orbital gyrus • Anterior orbital gyrus • Posterior orbital gyrus Sulci & Gyri on the inferior surface ©Dr.N.Mugunthan
  19. 19. Tentorial part: • Collateral sulcus (medial) • Occipito-temporal sulcus (lateral) • Medial occipito-temporal gyrus • Lateral occipito-temporal gyrus • Rhinal sulcus • Uncus • Parahippocampal gyrus • Lingual gyrus Sulci & Gyri on the inferior surface cont… ©Dr.N.Mugunthan
  20. 20. Broadmann mapping 52 areas in cerebral cortex ©Dr.N.Mugunthan
  21. 21. Types of cortical functional areas 3 Types of functional areas 1. Motor areas 2. Sensory areas 3. Association areas ©Dr.N.Mugunthan
  22. 22. Primary motor area (area 4)  Precentral gyrus (superolateral surface)  Motor homunculus  Control voluntary movements of contralateral side ©Dr.N.Mugunthan
  23. 23. Effects of lesion – primary motor area Contralateral Flaccid paralysis –initially ↓DTR +Ve Babinski sign Moderate recovery of function ©Dr.N.Mugunthan
  24. 24. Pre-motor area (area 6 & 8) Area 6- skillful acts (programming of movements) Upper part of area 6 – writing centre  Area 8 also known as frontal eye field (regulates voluntary conjugate movements) ©Dr.N.Mugunthan
  25. 25. Supplementary motor area  Continuation of area 6 on medial surface Function:  control complex movements  Elicits an urge to move Lesion :  Akinesia  UMN type paralysis (conjoint lesion of primary motor,premotor & supp.motor area) ©Dr.N.Mugunthan
  26. 26. Pre-frontal area (areas 9 to 12)  In front of premotor area  Highly developed in human Functions:  Regulates the depth of feeling  Abstract thinking  Mature judgement  Foresight & tactfulness (Silent area of brain) ©Dr.N.Mugunthan
  27. 27. Sensory areas 1. Primary sensory area 2. Secondary sensory area (only for somesthetic senses) 3. Sensory association area 4. Higher association area ©Dr.N.Mugunthan
  28. 28. Primary sensory area 1. Somesthetic area 2. Visual area 3. Auditory area ©Dr.N.Mugunthan
  29. 29. Somesthetic area Primary somesthetic area (area 3,1,2)  Located in post central gyrus (superolateral surface)  Functions: o Localises,analyses & discriminates different modalities of cutaneous senses (touch,pressure,position & vibration senses) o Sensory homunculus (sensation are somatotopically arranged) o Lower part of post central gyrus – taste centre (area43) ©Dr.N.Mugunthan
  30. 30. Paracentral lobule – receives sense of distension of bladder & rectum Primary somesthetic area – functions cont… ©Dr.N.Mugunthan
  31. 31. Secondary somesthetic area (supplementary) Upper lip of posterior ramus of lateral sulcus (lower part of pre & post central gyrus) Functions: Receives pain sensation Other modalities of cutaneous sensation ©Dr.N.Mugunthan
  32. 32. Somesthetic association area (area 5,7) Behind the post central gyrus (superior parietal lobule – area 5,7) ©Dr.N.Mugunthan
  33. 33. Higher association area for somesthetic senses (area 40) Supramarginal gyrus (area 40) Richly connected with area 5 & 7 Lesion: (area 40) Tactile agnosia (Astereognosis) Tactile aphasia ©Dr.N.Mugunthan
  34. 34. Visual senses 1. Primary visual area (area17) 2. Visual association area (area 18 & 19) 3. Higher visual association area (area 39) ©Dr.N.Mugunthan
  35. 35. Visual association area (area 18 &19) Parastriate area (area 18)/ visual area-II and Peristriate area(area19)/visual area- III Function: Area 18 & 19- occipital eye field (mediate conjugate movements involuntarily) 18 19 19 18 ©Dr.N.Mugunthan
  36. 36. Auditory senses 1. Primary auditory area (area 41) 2. Auditory association area (area42) 3. Higher auditory association area (area22) ©Dr.N.Mugunthan
  37. 37. Psychical cortex Anterior part of temporal lobe(temporal pole) Function : Memory (present & past) Dreams Hallucination (auditory & visual) ©Dr.N.Mugunthan
  38. 38.  Performed by left cerebral hemisphere (regardless of hand preference)  Hence left hemisphere- dominant or talking brain  Right hemisphere – non dominant or mute brain Speech function cont… ©Dr.N.Mugunthan
  39. 39. Dominant hemisphere has 4 speech centres (3 sensory & 1 motor centre) Sensory speech area: 1. Area 22 (higher auditory association area/ Wernicke’s area) 2. Area 39 (higher visual association area) 3. Area 40 (higher association area for somesthetic senses) Speech function cont… ©Dr.N.Mugunthan
  40. 40. Motor speech centre: 4. Area 44 & 45 (Broca’s area) Speech centres (motor & sensory) may be transferred to right hemisphere in child up to 6-8 years (in case of cerebral injury) Speech function cont… 45 44 ©Dr.N.Mugunthan
  41. 41. Area 22,39,40 – receives input from hearing,vision ,touch &proprioception Information processed in area 22 (post.part) Projected to Broca’s area thro’ arcuate fasciculus Sensory speech centre cont… ©Dr.N.Mugunthan
  42. 42. Lesions of speech centre  Lesion involving speech centre (dominant hemisphere) – aphasia 2 types: 1. Sensory aphasia 2. Motor aphasia Conduct aphasia – lesion of arcuate fasciculus (fluent/comprehension intact /repetition of spoken language is extremely difficult) ©Dr.N.Mugunthan
  43. 43. Main cerebral sulci: 1. Lateral sulcus (Sylvius) • Stem & 3 rami (posterior, ascending & anterior) 2. Central sulcus (Rolando) 3. Parieto-occipital sulcus 4. Calcarine sulcus Summary ©Dr.N.Mugunthan
  44. 44. Summary Functional areas :- 1. Motor areas 2. Sensory areas 3. Psychical areas ©Dr.N.Mugunthan
  45. 45. Motor areas :- 1. Primary motor area 2. Pre-motor area 3. Supplementary motor area 4. Pre-frontal area Summary cont… ©Dr.N.Mugunthan
  46. 46. Summary cont… Sensory areas:- 1. Primary sensory area 2. Secondary sensory area (only for somesthetic senses) 3. Sensory association area 4. Higher association area ©Dr.N.Mugunthan
  47. 47. Summary cont… Primary sensory areas:- 1. Somesthetic area 2. Visual area 3. Auditory area ©Dr.N.Mugunthan

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