CerebralCerebralCortexCortex

CerebralCerebralCortexCortex

Won Taek LeeWon Taek Lee, , M.D. Ph.D.M.D. Ph.D.Won Taek LeeWon Taek Lee, , M.D. Ph.D.M.D. Ph.D.

Department of Anatomy, Department of Anatomy, Yonsei University College of MedicineYonsei University College of Medicine

Department of Anatomy, Department of Anatomy, Yonsei University College of MedicineYonsei University College of Medicine

The layer of gray matter covering The layer of gray matter covering

the entire surface of cerebral hemispherethe entire surface of cerebral hemisphere

Migration of neurons from inner mantle layer ofMigration of neurons from inner mantle layer of

neural tubeneural tube

Accommodates enormous number of neuronsAccommodates enormous number of neurons

- - Large surface areaLarge surface area accommodates accommodates

more neurons than deep nucleimore neurons than deep nuclei

- - Gyri and sulciGyri and sulci also increase surface area also increase surface area

- - Laminar organizationLaminar organization also accommodates also accommodates

enormous number of neuronsenormous number of neurons

Cerebral CortexCerebral CortexCerebral CortexCerebral Cortex

Numerical DataNumerical Data

Total surface areaTotal surface area: 2200 cm: 2200 cm22 (2.5 ft (2.5 ft22))

about 1/3 ------ surface areaabout 1/3 ------ surface area about 2/3 ------ hidden in the sulciabout 2/3 ------ hidden in the sulci

ThicknessThickness: 1.5 mm (V I) - 4.5 mm (M I): 1.5 mm (V I) - 4.5 mm (M I)

Generally, thickest over the crest of the convolutionGenerally, thickest over the crest of the convolution and, thinnest in the depth of sulciand, thinnest in the depth of sulci

WeightWeight: 600 gm (40 % of total brain weight): 600 gm (40 % of total brain weight)

180 gm --------- neurons180 gm --------- neurons 420 gm --------- glial cells420 gm --------- glial cells

CerebralCerebral CortexCortexCerebralCerebral CortexCortex

Numerical DataNumerical Data

Number of neuronal cells in cerebral cortexNumber of neuronal cells in cerebral cortex

neurons ----------- neurons ----------- 10-15 billion10-15 billion

glial cells ----------glial cells ---------- 50 billion50 billion

Estimation of number of cortical neuronsEstimation of number of cortical neurons

von Economo and Koskinas (1925) von Economo and Koskinas (1925) 14.0 billion 14.0 billion

Shariff (1953)Shariff (1953) 6.9 billion 6.9 billion

Sholl (1956)Sholl (1956) 5.0 billion 5.0 billion

Pakkenberg (1966)Pakkenberg (1966) 2.6 billion 2.6 billion

CerebralCerebral CortexCortex

Subdivision of Cerebral CortexSubdivision of Cerebral Cortex

AllocortexAllocortex

Archicortex (Archipallium)Archicortex (Archipallium)

Palaeocortex (Paleopallium)Palaeocortex (Paleopallium)

IsocortexIsocortex

Neocortex (Neopallium)Neocortex (Neopallium)

cf. mesocortex, juxtallocortex, mesallocortexcf. mesocortex, juxtallocortex, mesallocortex

IsocortexIsocortex – – typicaltypical 6 6 layered cortexlayered cortex

I. I. Molecular LayerMolecular Layer

II. II. External Granular LayerExternal Granular Layer

III.III. External Pyramidal LayerExternal Pyramidal Layer

IV.IV. Internal Granular LayerInternal Granular Layer

V. V. Internal Pyramidal LayerInternal Pyramidal Layer

VI. Polymorphic LayerVI. Polymorphic Layer

Histological OrganizationHistological Organization

Cellular ElementsCellular Elements

1. 1. Pyramidal CellPyramidal Cell - - output neuronoutput neuron

giant pyramidal cell of Betzgiant pyramidal cell of Betz

2. Fusiform Cell ---2. Fusiform Cell --- modified pyramidal cellmodified pyramidal cell

3. 3. Granular (Stellate) CellGranular (Stellate) Cell

basket cell, double bouquet cell, bipolar cell,basket cell, double bouquet cell, bipolar cell,

chandlier cell, neurogliform cellchandlier cell, neurogliform cell

4. Horizontal Cell of Cajal (Retzius-Cajal cell)4. Horizontal Cell of Cajal (Retzius-Cajal cell)

5. Cells of Martinotti5. Cells of Martinotti

CerebralCerebral CortexCortex

1. Pyramidal Cell1. Pyramidal Cell

2. Fusiform Cell 2. Fusiform Cell

3. Granular (Stellate) Cell3. Granular (Stellate) Cell

4. basket cell4. basket cell

5. double bouquet cell 5. double bouquet cell

6. chandlier cell 6. chandlier cell

7. neurogliform cell7. neurogliform cell

8. Horizontal Cell of Cajal 8. Horizontal Cell of Cajal

9. Cells of Martinotti9. Cells of Martinotti

a: axona: axon

CerebralCerebral CortexCortex

I. I. Molecular LayerMolecular Layer

II. II. External Granular LayerExternal Granular Layer

III.III. External Pyramidal LayerExternal Pyramidal Layer

Line of Kaes-BechterewLine of Kaes-Bechterew

IV.IV. Internal Granular LayerInternal Granular Layer

Outer band of BaillargerOuter band of Baillarger

- Line of Gennari- Line of Gennari in area 17 in area 17

V. V. Internal Pyramidal LayerInternal Pyramidal Layer

Giant pyramidal cell of BetzGiant pyramidal cell of Betz

Inner Band of BaillargerInner Band of Baillarger

VI. VI. Polymorphic LayerPolymorphic LayerGolgi Golgi NisslNissl WeigertWeigert

1. corticocortical fiber1. corticocortical fiber association fiber association fiber

commissural fibercommissural fiber 2. thalamocortical fiber2. thalamocortical fiber - specific and non-specific- specific and non-specific

3. extrathalamic subcortical fiber3. extrathalamic subcortical fibercholinergic fiber - acetylcholinecholinergic fiber - acetylcholine basal nucleus of Meynertbasal nucleus of Meynert

mesolimbic dopaminergic fiber - dopaminemesolimbic dopaminergic fiber - dopamine ventral tegmental areaventral tegmental area serotonergic fiber – serotonine - raphe nuclei serotonergic fiber – serotonine - raphe nuclei norepinephrinergic fiber - norepinephrinenorepinephrinergic fiber - norepinephrine nucleus locus ceruleusnucleus locus ceruleus

Cortical Afferent FiberCortical Afferent FiberCortical Afferent FiberCortical Afferent Fiber

Cortical Afferent FiberCortical Afferent FiberCortical Afferent FiberCortical Afferent Fiber

1. association fiber 1. association fiber

2. commissural fiber2. commissural fiber

3. specific3. specific thalamocortical fiberthalamocortical fiber

4. non-specific4. non-specific thalamocortical fiberthalamocortical fiber

1. Corticofugal Fiber - Projection Fiber1. Corticofugal Fiber - Projection Fiber

corticostriate fibercorticostriate fiber corticothalamic fibercorticothalamic fiber corticorubral fiber corticorubral fiber corticotectal fiber corticotectal fiber corticopontine fiber corticopontine fiber cortico-olivary fiber cortico-olivary fiber corticobulbar fibercorticobulbar fiber corticospinal fibercorticospinal fiber

2. Corticocortical Fiber2. Corticocortical Fiber Association fiberAssociation fiberCommissural fiberCommissural fiber

Cortical Efferent FiberCortical Efferent FiberCortical Efferent FiberCortical Efferent Fiber

5. 5. association fiberassociation fiber

6. 6. commissural fibercommissural fiber

7. 7. corticostriate fibercorticostriate fiber

8. 8. corticorubral fiber corticorubral fiber

corticopontine fiber corticopontine fiber

corticobulbar fibercorticobulbar fiber

9. 9. corticospinal fibercorticospinal fiber

corticotectal fibercorticotectal fiber

10. 10. corticothalamic fiber corticothalamic fiber

Cortical Efferent FiberCortical Efferent FiberCortical Efferent FiberCortical Efferent Fiber

A. A. pyramidal neuronpyramidal neuron

B. excitatoryB. excitatorygranular cellgranular cell

C.C. inhibitoryinhibitorygranular cellgranular cell

1. 1. afferentafferent fiber fiber

2.2. efferent fiberefferent fiber

3.3. corticothalamic fibercorticothalamic fiber

Columnar Cortical Unit and Cortical CircuitaryColumnar Cortical Unit and Cortical CircuitaryColumnar Cortical Unit and Cortical CircuitaryColumnar Cortical Unit and Cortical Circuitary

A. A. Homotypical isocortexHomotypical isocortex

-------------- association cortexassociation cortex

B. Heterotypical isocortexB. Heterotypical isocortex

1. granular cortex 1. granular cortex

------ primary sensory cortexprimary sensory cortex

V I (17), S I (3), A I (41) V I (17), S I (3), A I (41)

2. agranular cortex2. agranular cortex

------ motor cortexmotor cortex

M I (4), PM (6)M I (4), PM (6)

Regional Variation of Cortical LaminationRegional Variation of Cortical LaminationRegional Variation of Cortical LaminationRegional Variation of Cortical Lamination

Von Economo’s classification of cortical typesVon Economo’s classification of cortical typesVon Economo’s classification of cortical typesVon Economo’s classification of cortical types

1. agranular, 2. frontal, 3. parietal, 4. polar, 5. granular1. agranular, 2. frontal, 3. parietal, 4. polar, 5. granular

1. agranular, 2. frontal, 3. parietal, 4. polar, 5. granular1. agranular, 2. frontal, 3. parietal, 4. polar, 5. granular

Phrenology of Gall and SpurzheimPhrenology of Gall and Spurzheim

Clinical evidencesClinical evidences

Broca’s area (1861)Broca’s area (1861)

Jacksonian epilepsy (1864)Jacksonian epilepsy (1864)

Experimental evidencesExperimental evidences

Fritsch and Hitzig (1870) --- motor cortexFritsch and Hitzig (1870) --- motor cortex

von Gudden (1870) ---- visual cortexvon Gudden (1870) ---- visual cortex

Ferrier (1873) ---- auditory cortexFerrier (1873) ---- auditory cortex

Functional Localization of Cerebral CortexFunctional Localization of Cerebral CortexFunctional Localization of Cerebral CortexFunctional Localization of Cerebral Cortex

Albertus MagnusAlbertus Magnus(1206-1280)(1206-1280)

Phrenology of Gall (1758-1828)Phrenology of Gall (1758-1828)and Spurzheim (1776-1832)and Spurzheim (1776-1832)

PET (positron emission tomography) scanPET (positron emission tomography) scan

based on cytoarchitectonic studiesbased on cytoarchitectonic studies

Campbell (1905) -------- Campbell (1905) -------- about 20 areasabout 20 areas

Brodmann (1909) ------Brodmann (1909) ------ 47 areas47 areas

- most popular- most popular

Vogt and Vogt (1919) -Vogt and Vogt (1919) - over 200 areasover 200 areas

von Economo (1929) --von Economo (1929) -- 109 areas109 areas

Morphological Classification of Cortical AreasMorphological Classification of Cortical AreasMorphological Classification of Cortical AreasMorphological Classification of Cortical Areas

Brodmann’s cytoarchitectorial map (Lateral surface)Brodmann’s cytoarchitectorial map (Lateral surface)

Brodmann’s cytoarchitectorial map (Lateral surface)Brodmann’s cytoarchitectorial map (Lateral surface)

Sensory areaSensory area primary sensory areaprimary sensory area secondary sensory areasecondary sensory area

Motor areaMotor area

primary motor areaprimary motor area secondary motor areasecondary motor area supplementary motor areasupplementary motor area

Association areaAssociation area

parietal, occipital and temporal cortexparietal, occipital and temporal cortex - conceptual elaboration of sensory data- conceptual elaboration of sensory data prefrontal (frontal) cortexprefrontal (frontal) cortex - judgement, foresight- judgement, foresight

Functional Localization of Cerebral CortexFunctional Localization of Cerebral CortexFunctional Localization of Cerebral CortexFunctional Localization of Cerebral Cortex

Somesthetic Area (Somesthesia)Somesthetic Area (Somesthesia) S I, S IIS I, S II

Visual Area (vision)Visual Area (vision) V I, V IIV I, V II

Auditory Area (Hearing)Auditory Area (Hearing) A I, A IIA I, A II

Vestibular Area (Equilibrium)Vestibular Area (Equilibrium)

Gustatory Area (Taste)Gustatory Area (Taste)

Olfactory Area (Smell)Olfactory Area (Smell)

Sensory AreasSensory AreasSensory AreasSensory Areas

S I S I ----- 3, 1, 2 (postcentral gyrus)----- 3, 1, 2 (postcentral gyrus)

afferernts: ventrobasal complex (VPLc, VPM)afferernts: ventrobasal complex (VPLc, VPM)

discrimination of position and intensity of sensationdiscrimination of position and intensity of sensation

S II S II ---- superior bank of lateral fissure---- superior bank of lateral fissure

no clinical disordersno clinical disorders

Somesthetic Association CortexSomesthetic Association Cortex

------- 5, 7 (parietal lobule, precuneus)------- 5, 7 (parietal lobule, precuneus)

afferents: S I, LP of thalamusafferents: S I, LP of thalamus

integration of geneal sensation with past experienceintegration of geneal sensation with past experience

tactile agnosia, astereognosistactile agnosia, astereognosis

Somesthetic AreaSomesthetic AreaSomesthetic AreaSomesthetic Area

Sensory HomunculusSensory HomunculusSensory HomunculusSensory Homunculus

ThalmocorticalThalmocortical

connectionconnection

(VPLc (VPLc S I)S I)

Central regionCentral region

--- cutaneous (3b, 1)--- cutaneous (3b, 1)

Peripheral regionPeripheral region

--- deep (3a, 2)--- deep (3a, 2)

PrimaryPrimarySomestheticSomesthetic

AreaArea

PrimaryPrimarySomestheticSomesthetic

AreaArea

SecondarySecondary

Somesthetic Somesthetic

Area (SII)Area (SII)

superior bank of superior bank of

lateral fissurelateral fissure

V I ----- V I ----- 17 (striate cortex - line of Gennari)17 (striate cortex - line of Gennari)

greatly thickened outer band of Baillargergreatly thickened outer band of Baillarger

heterotypical isocortexheterotypical isocortex

afferent: LGd of thalamusafferent: LGd of thalamus

visual field defect:visual field defect:

homonymous quadranopsia and macular sparinghomonymous quadranopsia and macular sparing

V II ---- V II ---- 18, 19 (visual association area)18, 19 (visual association area)

afferents: V I, pulvinar of thalamusafferents: V I, pulvinar of thalamus

integration of vision with past experienceintegration of vision with past experience

visual agnosiavisual agnosia

cf. occipital eye fieldcf. occipital eye field

Visual CortexVisual CortexVisual CortexVisual Cortex

VisualVisualAreasAreas

V4V4(color)(color) FaceFace

recognitionrecognitionPerceivePerceive

Facial ExpressionFacial Expression

VisualVisualassociationassociation

areasareas

A I ----- A I ----- 41, 42 (trannsverse temporal gyrus of Heschl)41, 42 (trannsverse temporal gyrus of Heschl)

heterotypical isocortexheterotypical isocortex

afferents: MGv of thalamus - core projectionafferents: MGv of thalamus - core projection

slight diminution in auditory acuityslight diminution in auditory acuity

A II ---- A II ---- 22 (Wernike's area of original connotaion)22 (Wernike's area of original connotaion)

not well-definednot well-defined

afferents: non-laminar part (MGm, MGd) – belt projectionafferents: non-laminar part (MGm, MGd) – belt projection A IA I

auditory agnosia - sensory aphasiaauditory agnosia - sensory aphasia

Auditory CortexAuditory CortexAuditory CortexAuditory Cortex

AuditoryAuditoryAreasAreas

PlanumPlanumtemporaletemporale

AuditoryAuditoryAreasAreas

A I ----- A I ----- 41, 4241, 42

A II ---- A II ---- 2222

Vestibular AreaVestibular Area

Area 3a and 2v of S IArea 3a and 2v of S I

afferents: VPLoafferents: VPLo

[superior temporal gyrus anterior to A I][superior temporal gyrus anterior to A I]

Gustatory AreaGustatory Area

Area 43 (inferior end of postcentral gyrus)Area 43 (inferior end of postcentral gyrus)

afferents: VPMpcafferents: VPMpc

Olfactory AreaOlfactory Area

Piriform Lobe - Limbic SystemPiriform Lobe - Limbic System

Other Primary Sensory AreasOther Primary Sensory AreasOther Primary Sensory AreasOther Primary Sensory Areas

primary Motor Area (M I)primary Motor Area (M I)

Premotor Area (PM) Premotor Area (PM)

Supplementary Motor Area (SMA)Supplementary Motor Area (SMA)

Frontal Eye FieldFrontal Eye Field

Motor AreasMotor AreasMotor AreasMotor Areas

Motor HomunculusMotor HomunculusMotor HomunculusMotor Homunculus

M I ------- 4 M I ------- 4

precentral gyrus of lateral surfaceprecentral gyrus of lateral surface

anterior part of paracentral lobuleanterior part of paracentral lobule

heterotypical agranular cortexheterotypical agranular cortex

giant pyramidal cell of Betzgiant pyramidal cell of Betz

afferents: premotor area, SMA, S Iafferents: premotor area, SMA, S I

VLc, VPLo of thalamusVLc, VPLo of thalamus

Motor HomunculusMotor Homunculus

Upper Motor Neuron (UMN) syndromeUpper Motor Neuron (UMN) syndrome

Primary Motor AreaPrimary Motor Area

Premotor Area (PM) ------Premotor Area (PM) ------ lateral surface of 6lateral surface of 6

afferents: VLc, VPLo of thalamus from cerebellumafferents: VLc, VPLo of thalamus from cerebellum

Supplementary Motor Area (SMA)Supplementary Motor Area (SMA)

---------------------------------------------------- medial surface of 6medial surface of 6

afferents: VLo, Vapc of thalamus from basal gangliaafferents: VLo, Vapc of thalamus from basal ganglia

Frontal Eye Field ----------Frontal Eye Field ---------- 88

voluntary tracking movementvoluntary tracking movement

Other Motor AreasOther Motor Areas

Brodman’s Map of Motor and Sensory AreasBrodman’s Map of Motor and Sensory Areas

Language Areas ----- 22, 39, 40, 44, 45Language Areas ----- 22, 39, 40, 44, 45

Posterior Parietal Association AreaPosterior Parietal Association Area

------ ------ 5, 75, 7 (39, 40)(39, 40)body imagebody image

Temporal Association Area Temporal Association Area ------ ------ 20, 21, 37, 20, 21, 37, 38 38 (22)(22)

multisensory integration, conceptual ideationmultisensory integration, conceptual ideation

Prefrontal Association AreaPrefrontal Association Area

----- ----- 9, 10, 11, 12, 46, 47 9, 10, 11, 12, 46, 47 (44, 45)(44, 45)

judgement, foresight, personalityjudgement, foresight, personality

Association AreasAssociation Areas

Order of Cortical MaturationOrder of Cortical Maturation

11

2233

33

33

22

11

11

AgnosiaAgnosia

Tactile agnosiaTactile agnosia Visual agnosiaVisual agnosia

AlexiaAlexia Auditory agnosiaAuditory agnosia

ApraxiaApraxia

AphasiaAphasia

Wernicke’s (receptive) aphasiaWernicke’s (receptive) aphasia Broca’s (Motor) aphasiaBroca’s (Motor) aphasia conduction aphasiaconduction aphasia global aphasiaglobal aphasia

Disorders of Association CortexDisorders of Association CortexDisorders of Association CortexDisorders of Association Cortex

ApraxiaApraxiaApraxiaApraxia

The inability to execute a voluntary motor movement despite being The inability to execute a voluntary motor movement despite being able to demonstrate normal muscle function.able to demonstrate normal muscle function.

Sensory Language Area (Wernike's area) ---- Sensory Language Area (Wernike's area) ---- 22, 39, 4022, 39, 40

ReceptiveReceptive AphasiaAphasia - - area 22area 22 defect in comprehension, good spontaneous speechdefect in comprehension, good spontaneous speech AnomicAnomic AphasiaAphasia - - word finding difficultyword finding difficulty JargonJargon aphasiaaphasia - - fluent, but unintelligiable jargon fluent, but unintelligiable jargon

39 (supramarginal gyrus), 40 (angular gyrus)39 (supramarginal gyrus), 40 (angular gyrus)

Superior Longitudinal FasciculusSuperior Longitudinal Fasciculus

ConductionConduction AphasiaAphasia good comprehension, good spontaneous speechgood comprehension, good spontaneous speech poor repetition, poor responsepoor repetition, poor response

Motor Language Area (Broca’s area) --- 44, 45Motor Language Area (Broca’s area) --- 44, 45

MotorMotor ApahsiaApahsia good comprehension, no speechgood comprehension, no speech

Language AreasLanguage Areas

Language Areas (Geschwind Model)Language Areas (Geschwind Model)

Photograph of the brain of Photograph of the brain of Paul Broca’s patient called Paul Broca’s patient called “Tan” (real name is “Tan” (real name is Leborgne).Leborgne).

Broca’s AreaBroca’s AreaBroca’s AreaBroca’s Area

Pars triangularis and pars Pars triangularis and pars opercularis of the inferior opercularis of the inferior frontal gyrus of dominant frontal gyrus of dominant hemisphere.hemisphere.

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

PET (positron emission tomography) scanPET (positron emission tomography) scan

Composite radioisotope brain scanComposite radioisotope brain scan

Cerebral Dominance (Lateralization, Asymmetry)Cerebral Dominance (Lateralization, Asymmetry)

Dominant HemisphereDominant Hemisphere

LanguageLanguage

– – speech, writingspeech, writing

CalculationCalculation

Non-dominant HemisphereNon-dominant Hemisphere

Spatial Perception (3D subject)Spatial Perception (3D subject)

SingingSinging

Playing musical instrumentPlaying musical instrument

LanguageLanguage

SpeechSpeech

WritingWriting

CalculationCalculation

3D perception3D perception

SingingSinging

Playing Musical Playing Musical

instrumentinstrument

Roger Sperry Roger Sperry

(1913-1994)(1913-1994)

1981 Nobel 1981 Nobel LaureateLaureate

                                                                                       

Split BrainSplit BrainSplit BrainSplit Brain

CommissuratomyCommissuratomy

(split corpus callosum)(split corpus callosum)

Two minds in one brain?Two minds in one brain?

Frontal Granular CortexFrontal Granular Cortex

Lateral Prefrontal Association AreaLateral Prefrontal Association Area

------ ------ 9, 10, 469, 10, 46

judgement, foresight, problem solvingjudgement, foresight, problem solving

Orbitofrontal CortexOrbitofrontal Cortex ------ ------ 11, 12, 47 11, 12, 47

emotion, olfaction, personalityemotion, olfaction, personality

Case of Case of Phineas GagePhineas Gage

Prefrontal Leucotomy of Prefrontal Leucotomy of MonizMoniz and and FreemanFreeman

Prefrontal Association AreasPrefrontal Association Areas

Phineas GagePhineas Gage(1823-1861, accident in 1848)(1823-1861, accident in 1848)

Phineas Gage’s lesion reconstructedPhineas Gage’s lesion reconstructed(H. Damasio and R. Frank, 1992)(H. Damasio and R. Frank, 1992)

Prefrontal LeucotomyPrefrontal Leucotomy(Frontal Lobotomy)(Frontal Lobotomy)

Antonio Egas MonizAntonio Egas Moniz

Conceptual Framework of Cerebral FunctionConceptual Framework of Cerebral FunctionConceptual Framework of Cerebral FunctionConceptual Framework of Cerebral Function