cerebral cortex

Nabeel Kouka, Nabeel Kouka, MD, DO, MBAMD, DO, MBAwww.brain101.infowww.brain101.info

Nabeel Kouka, Nabeel Kouka, MD, DO, MBAMD, DO, MBAwww.brain101.infowww.brain101.info

CerebralCerebralCortexCortex

CerebralCerebralCortexCortex

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

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

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

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?

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 (Arcuate) FasciculusSuperior Longitudinal (Arcuate) 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 speech, agraphiagood comprehension, no speech, agraphia

Language AreasLanguage Areas

Arcuate FasciculusArcuate FasciculusThe groups of fibers that connect Broca's area with Wernicke's area (these fibers The groups of fibers that connect Broca's area with Wernicke's area (these fibers connect to the angular gyrus) and are located below the supramarginal gyrus. connect to the angular gyrus) and are located below the supramarginal gyrus.

According to Geschwind, damage to this area results in Conduction AphasiaAccording to Geschwind, damage to this area results in Conduction Aphasia

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

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

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

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

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

Composite radioisotope brain scanComposite radioisotope brain scan

Sensory HomunculusSensory HomunculusSensory HomunculusSensory Homunculus

Motor HomunculusMotor HomunculusMotor HomunculusMotor Homunculus

DiencephalonDiencephalon

Dorsal surfaceDorsal surface

DiencephalonDiencephalon

Ventral surfaceVentral surface

Diencephalon

Medial Surface

THALAMUSTHALAMUS

Classification of Thalamic NucleiClassification of Thalamic NucleiClassification of Thalamic NucleiClassification of Thalamic Nuclei

I. I. Lateral Nuclear GroupLateral Nuclear Group

II.II. Medial Nuclear GroupMedial Nuclear Group

III.III. Anterior Nuclear GroupAnterior Nuclear Group

IV.IV. Posterior Nuclear GroupPosterior Nuclear Group

V.V. Metathalamic Nuclear GroupMetathalamic Nuclear Group

VI.VI. Intralaminar Nuclear GroupIntralaminar Nuclear Group

VII.VII. Thalamic Reticular NucleusThalamic Reticular Nucleus

Classification of Thalamic NucleiClassification of Thalamic NucleiClassification of Thalamic NucleiClassification of Thalamic Nuclei

Basal Basal Ganglia Ganglia Basal Basal

Ganglia Ganglia

Traditional Concepts of Traditional Concepts of Basal GangliaBasal Ganglia

Corpus StriatumCorpus Striatum

Caudate NucleusCaudate Nucleus

Lenticular Nucleus PutamenLenticular Nucleus Putamen

Globus Pallidus Globus Pallidus PaleostriatumPaleostriatum Pallidum Pallidum

Corpus Amygdaloideum Corpus Amygdaloideum ArchistriatumArchistriatum

NeostriatumNeostriatum Striatum Striatum

Basal Ganglia Introduction Basal Ganglia Introduction Basal Ganglia Introduction Basal Ganglia Introduction

Afferent Connections of Basal GangliaAfferent Connections of Basal Ganglia

Efferent Connections of Basal GangliaEfferent Connections of Basal Ganglia

Clinical FeatureClinical Feature

Principal Pathologic Lesion:Principal Pathologic Lesion:

Corpus StriatumCorpus Striatum (esp. caudate nucleus) (esp. caudate nucleus) and Cerebral Cortexand Cerebral Cortex

- Predominantly - Predominantly autosomal dominantlyautosomal dominantly inherited chronic fatal diseaseinherited chronic fatal disease (Gene: chromosome 4)(Gene: chromosome 4)- Insidious onset: Usually 40-50- Insidious onset: Usually 40-50- Choreic movements in onset- Choreic movements in onset- Frequently associated with- Frequently associated with emotional disturbancesemotional disturbances- Ultimately, grotesque gait and sever- Ultimately, grotesque gait and sever dysarthria, progressive dementiadysarthria, progressive dementia ensues.ensues.

HUNTINGTON’S CHOREAHUNTINGTON’S CHOREA

SYDENHAM’S CHOREASYDENHAM’S CHOREASYDENHAM’S CHOREASYDENHAM’S CHOREA

- Complication of- Complication of Rheumatic FeverRheumatic Fever- Fine, disorganized , and - Fine, disorganized , and random movements ofrandom movements of extremities, face andextremities, face and tonguetongue- Accompanied by - Accompanied by Muscular HypotoniaMuscular Hypotonia- Typical exaggeration of- Typical exaggeration of associated movements associated movements during voluntary activityduring voluntary activity- Usually recovers- Usually recovers spontaneously spontaneously in 1 to 4 monthsin 1 to 4 months

Clinical FeatureClinical Feature

Principal Pathologic Lesion: Principal Pathologic Lesion: Corpus StriatumCorpus Striatum

HEMIBALLISMHEMIBALLISMHEMIBALLISMHEMIBALLISM

- Usually results from CVA- Usually results from CVA (Cerebrovascular Accident)(Cerebrovascular Accident) involving subthalamic nucleusinvolving subthalamic nucleus- sudden onset- sudden onset- - Violent, writhing, involuntaryViolent, writhing, involuntary movements of wide excursionmovements of wide excursion confined to confined to one half of the bodyone half of the body- The movements are continuous- The movements are continuous and often exhausting but ceaseand often exhausting but cease during sleepduring sleep- Sometimes fatal due to exhaustion- Sometimes fatal due to exhaustion- Could be controlled by- Could be controlled by phenothiazines and stereotaxicphenothiazines and stereotaxic surgery surgery

Clinical FeatureClinical Feature

Lesion: Lesion: Subthalamic NucleusSubthalamic Nucleus

Muhammad Ali in Alanta OlympicMuhammad Ali in Alanta Olympic

Parkinson’s DiseaseParkinson’s Disease

Disease of mesostriatal Disease of mesostriatal dopaminergic systemdopaminergic system

PDPD

normalnormal

Substantia Nigra, Substantia Nigra, Pars Compacta (SNc)Pars Compacta (SNc)

DOPAminergic NeuronDOPAminergic Neuron

Slowness of MovementSlowness of Movement- - Difficulty in Initiation and Cessation Difficulty in Initiation and Cessation of Movementof Movement

Clinical Feature (1)Clinical Feature (1)

Parkinson’s Disease - Paralysis AgitansParkinson’s Disease - Paralysis Agitans

Clinical Feature (2)Clinical Feature (2)

Resting TremorResting TremorParkinsonian PostureParkinsonian PostureRigidity-Cogwheel RigidityRigidity-Cogwheel Rigidity

Parkinson’s Disease Parkinson’s Disease

Paralysis AgitansParalysis Agitans

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

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