Cortical Function

CORTICAL FUNCTION

dr. Paulus Anam Ong Sp.Sdr. Yustiani Dikot Sp.S(K)

Bagian I.P. Saraf RSHS FKUP

CEREBRUM / FOREBRAIN

CONSIST OF 2 HEMISPHERE WHICH IS NOT SYMETRICAL IN SHAPE AND FUNCTION

THE LARGEST PART OF THE HUMAN BRAIN

COVERED BY GRAY MATTER CALLED CORTEX WHICH WAS FOLDED MADE GYRI AND SULCI

Part Of Cerebral Cortex

CEREBRAL CORTEX

CONSIST OF SIX LAYERS, THE THICHNESS VARIES IN DIFFERENT

REGIONS

VIEWED LATERALLY COMPOSED OF FOUR LOBES, BROODMAN

DEVIDED IN 47 AREAS WHICH SPECIFIC PART RESPECT FOR A

CERTAIN ASPECT OF FUNCTION

FUNCTION ARE INTEGRATION IN DISCRIMINATIVE AND

COGNITIVE PROCESSES RELATING TO AFFECTIVE BEHAVIOR,

MOTOR FUNCTION, SOMATOSENSORY PERCEPTION,

INTEGRATION AND MEMORY FUNCTION PERCEPTION MOTIVATION MOVEMENT

Functional Areas of The Cerebrum

INTEGRATION FIBRES

INTEGRATION IN ONE HEMISPHERE

ASSOCIATION FIBRES

INTEGRATION BETWEEN TWO HEMISPHERE

COMMISURE FIBRES/CORPUS CALLOSUM

INTEGRATION WITH OTHER PART OF CNS

PROJECTION FIBRES

Right and Left Hemisphere Function

Right and Left Hemisphere Function

THE 47 AREAS

Consist of

PRIMARY / PRINCIPLE RECEPTIVE AREA

ASSOCIATION AREA

INTEGRATION WITH OTHER PART OF

THE HEMISPHERE / BRAIN

Homonculus Cerebri

The Lateral Aspect of Cerebrum

The Medial Aspect of Cerebrum

Frontal Lobe Parts

FRONTAL LOBE FUNCTION

1. PRECENTRAL GYRUS (MOTOR CORTEX)

• Contralateral movement face, arm, leg, trunk

2. BROCA’S AREA (DOMINANT HEMISPHERE)

• Expressive centre for speech

3. A.SUPPLEMENTORY MOTOR AREA and B. frontal eye field

A.More involved in providing drive for initiation of movement than executing movement

B.Voluntary eyes movement on opposite stimulation

4. PREFRONTAL AREAS

• Personality and Initiative

5. PRECENTRAL LOBULE

• Cortical Inhibition of bladder and bowel voiding

IMPAIREMENT OF FRONTAL LOBE FUNCTION

1. PRECENTRAL GYRUS

Monoplegia or hemiplegia depending on extent of damage

2. BROCA’S AREA

Broca’s dysphasia

3. SUPPLEMENTARY MOTOR AREA and frontal eye field

Lack of initiation and Paralysis of head and eye movement to

opposite site

5. PRECENTRAL GYRUS

Incontinence of urine and fecal

Loss of cortical inhibition

A.ORBITOFRONTAL SYNDROME 1. Poor judgement2. Disinhibition3. Emotional lability

B. FRONTAL CONVEXITY SYNDROME Apathy Indifference Poor abstract thought

C. MEDIAL FRONTAL SYNDROME Akinetic Incontinent Sparse verbal output

Associated with :1. Primitive reflexes (gasp,pout, etc.)2. Disturbance of gait (gait apraxia)3. Resistance to passive movements of the limbs

(paratonia)

4. PREFRONTAL AREASChange personality with antisocial behavior / loss of inhibition

Parietal Lobe Parts

PARIETAL LOBES FUNCTION

1. POSTCENTRAL GYRUS (primary sensory Cortex) and Superior Parietal Lobule (secondary sensory association area)

• Receives afferent pathways for appreciation of posture, touch and passive movement

• Coordination, integration and refinement of sensory input, tactile localization, discrimination, sterognosis

2. Inferior parietal lobule: posterior tertiarry are that combines information from 3 posterior lobes: parietal, temporal, occipital

SUPRAMARGINAL AND ANGULAR GYRI

• DOMINANT HEMISPHERE

• Language: From wernicke’s language area Integration of auditory and visual aspects comprehension in

• Skill of handling numbers/calculation

• NON-DOMINANT HEMISPHERE

1. Concept of body imaged and the awareness of the external environment and ability to construct shape

PARIETAL LOBE IMPAIRMENT

1. DISTURBED in• Postural sensation• Sensation of passive movement• Accurate localisation of light touch• Two point discrimination

2. WERNICKE’S DYSPHASIANON-DOMINANT

• Anosognosia• Dressing apraxia• Geographical apraxia• Constructional apraxia

DOMINANT : (Gertman’s Syndrome)• Right and left limbs disorientation• Finger agnosia• Acalculation• Agraphia

Temporal Lobe Parts

LOBUS TEMPORAL FUNCTION

1.Primary AUDITORY CORTEX (Heschl’s gyrus, BA 41,42)• Dominant Hearing of Language• Non-Dominant Hearing of sound, rhythm and music

2 Wernicke area: stretch over tertiary association of parietal, temporal, occipital

Dominant: language comprehension Non dominant: perception of music

2.THE MIDDLE AND INFERIOR TEMPORAL GYRI• Learning and Memory

3. THE LIMBIC LOBE• Sensation of olfaction, Emosional, Affective behavior

4.VISUAL PATHWAY

TEMPORAL LOBE IMPAIRMENT

1. AUDITORY CORTEX (Cortical deafness)• DOMINANT Difficulty in hearing spoken sounds• NON-DOMINANT Amusia• Auditory hallucinations

2. MIDDLE AND INFERIOR TEMPORAL GYRI • Disturbed memory / learning

3. LIMBIC LOBE• Olfactory hallucination with complex partial seizures• Aggressive or antisocial behavior• Inability to establish new memories

4. OPTIC RADIATION• Upper homonymous qudrantanopia

Occipital Lobe Parts

OCCIPITAL LOBE FUNCTION

Perception of vision (The visual cortex)

Lies along the banks of the calcarine sulcus

1. The Striate cortex: Primary visual cortex (BA 17)2. Parastriate cortex: Association visual cortex (BA 18): Synthesize visual impression, integrate them with other

sensory modalities and aid in formation of visual memory traces.

Area where parietal and occipital lobes meet: perception of spatial relationship,

visuokinesthetic motor engrams

prepositional consruction in language comprehension and

speech

OCCIPITAL LOBE IMPAIRMENT

1. HOMONIMOUS HEMIANOPSIA2. CORTICAL BLINDNESS

• Extensive bilateral cortical lesions of the striate cortex3. ANTON’S SYNDROME

• Involvement of both the striate and the parastriate cortices affects the interpretation of vision

• Unaware of the visual loss and denies its presence4. BALINT’S SYNDROME

• Simultanagnosia5. VISUAL HALLUCINATIONS

• Elementary – unformed – appearing as patterns6. VISUAL ILLUSIONS (Non-dominant)

• Micropsia / macropsia• Disappearance of colour

7. PROSOPAGNOSIA• Able to see a familiar face but cannot named it

Balint’s syndrome

Synonim: Balinnt-Holmes syndrome

(1909), Occularr apraxia ; optic ataxia

Bilateral parieto-occipital disease

Inability to direct the eyes to a certain

point in the visual field despite intact eye

movement.

End of Session

Mental Status

5 basic element that build mental status

1.1. Arousal Mechanism ( alertness, attention, Arousal Mechanism ( alertness, attention, concentration)concentration)

2.2. OrientationOrientation

3.3. LanguageLanguage

4.4. MemoryMemory

5.5. Higher cortical functionHigher cortical function

Basic element of mental status

Higher cortical function

Memory

Concentration

Attentioni

Arousal

Language

Basic element of cogntion (Marshall,Mayer.1997)

• Arousal mechanism

• Bahasa & memori: well developed and localized basic element elemen

• Higher cortical function: depend on the 3 basic element

Language The basic tool of human communication and

crucial in assessing most cognitive abilities

Must be establish early in the course of mental status testing due to most of the mental test are verbal oriented e.g verbal memory test, oral calculation, proverb test

Terminology Dysarthria: specific disorder of articulation in which

basic language (grammar, comprehension & word choice) is intact

Dysprosody: an interruption of speech melody (inflection and rhyme) that caused monotonal, halting, can at times mimic a foreign accent

Aphasia: a true deficit of higher integrative language processing, patient produces errors of grammar and word choice or has a defect in comprehension

Terminology Alexia: loss of (any level of) reading ability in

previously literate person. Dyslexia: a specific developmental learning disorders

of children who have normal intelligence, yet experience unusual difficult in learning to read

Agraphia: an acquired disturbance in writing. Specifically refers to errors of language and not to problem with the actual formation of letter or poor handwriting

Aphasia Def: an acquired language impairment due to

damage to language areas of the brain (left hemisphere)

Characterized by defects of: Word selection language production language comprehension

Affect not only spoken, but also written language both comprehension (alexia) and production (agraphia)

Etiology of aphasia Acute

ischemic stroke (embolic/ thrombotic) in the distribution of middle cerebral artery

Cerebral hemorhage (hipertension, AVM, Aneurysm, Trauma

Slowly progressive: brain tumor Degenerative process: Alzheimer disease, Primary

Progressive Aphasia Transient: TIA, epileptic seizures

Aphasia 95% result from left hemisphere lesions

‘cause 95% of right handed individual and 70% of left handed are left hemisphere dominant for language

Crossed aphasia: aphasia after lesion of right hemisphere in a right handed individual

Primary Language Area(perisylvian area)

Area Broca Area Wernicke

Fasikulus Arcuatus

Girus postsentralis

Girus temporalis superiorSulkus lateralis

Girus presentralis

Language model of Wernicke-Geswind

kanankiri

Perisylvian area Aphasia most often caused by damage of

perisylvian language, that comprises of: Broca’s area: motor programming of speech Broca

aphasia Wernicke’s area: critical for auditory comprehension of

spoken words Wernicke aphasia Arcuate fasciculus: links Broca’s and Wernicke’s areas,

important for repetition Conduction aphasia

Extra perisylvian aphasias Aphasia may also caused by lesions that

do not directly damage the perisylvian language area, but isolate them from brain regions involved in semantic processing and production of volitional speech Transcortical aphasias

Clinical evaluation Fluency Naming Repetition Auditory comprehesion

Fluency Fluent aphasias

plentiful verbal output, well articulated, easy produced utterances of relatively normal length and prosody (i.e., variation of pitch, loudness, rhythm).

Lesions: post Rolandic cortex Non Fluent aphasia:

sparse, effortful utterances of short phrase length and disrupted prosody

Lesion: pre-Rolandic cortex

Naming All aphasic patients exhibit naming

impairment, or anomia, usually in combination with other language deficits

Isolated anomia anomic aphasia

Auditory comprehension Most aphasic patients show auditory

processing defective Anterior lesions result in relatively mild

auditory comprehension impairment, whereas posterior lesions (esp. Wernicke’s area) result in significant impairment of auditory processing

Repetition Requires intact perisylvian language area Perisylvian aphasias: repetition distrubed Extra-perisylvian aphasia: preserved of

repetition

Classification of Aphasia

Broca’s AreaExecutive or motor for

production of language

Broca’s dysphasia Motor dysphasia

Nonfluent / hesitant speech Telegraphic speech Comprehension – relative

preserved Repetition – poor Handwriting- poor

Wernick’s Area–Receptive Area

Wernicke’s dysphasia Comprehension – Impaired Speech fluent but nonsensical Neologism Paraphasia – half right words Patient unaware of language

problems Repetition: relative preserved Hand writing poor

Conduction Aphasia

Speech nonsensical but fluent

Comprehension - normal Repetition - poor

Global Aphasia

Non-fluent speech Comprehension impaired Repetition - poor

Boston Aphasia ClassificationAphasia syndromes Fluency Naming Repetition Auditory

Comprehension

Broca aphasia Non-fluent - - +

Wernicke aphasia Fluent - - -

Conduction aphasia Fluent - - +

Gobal aphasia Non-fluent - - -

Transcortical motor aphasia Non-fluent - + +

Transcortical sensory aphasia Fluent - + -

Mixed transcortical aphasia Non-fluent - + -

Anomia aphasia Fluent - + +

+: relatively preserved -: relatively disturbed

Memory

Memory

Involves :1. Recognition2. Registration3. Recall – Retrieval

Anatomical basis of memory Hippocampus

The Anatomical Basis of Memory

Test of Memory1. Immediate memory2. Recent memory3. Remote memory

Disorder of Memory(Amnesia Syndrome)

1. Retrograde amnesia Impairment of memory for events that

antedate illness or injury

2. Anterograde amnesia Inability to learn new verbal or non-verbal

information from onset of illness or injury

Disorders of Memory Retrieval Senescence – AAMI (Age Associated Memory

Impairment) –retrieval of stored memory slow but accurate

Depression – disorder in motivation and concentration

Dementia – especially recent memories MCI- mild cognitive impairment amnestic type; a

pre-dementia stage

Constructional ability Capacity to draw or construct two or three

dimensional figures or shapes Task

Copying line drawing Drawing to command Reconstructing block designs

Parietal lobe dysfunction Right hemisphere produces higher inciden and severity

than the left.

Constructional Abilities

Stimulus Results

Copying Figures

Constructional Abilities

Copying Figures

Higher Cortical Function Attention Language Memory

Consists of : Manipulation of well learned material Abstract thinking Arithmatic computation etc

Basic buiding blocks for

development of higher

cortical function

1. Evaluation

1. The fund of acquired information or the store of knowlegde

• Assessed by :1. Simple verbal test of vocabulary2. General information/ knowledge3. Proverb interpretation

2. Manipulation of old knowledge

Ability to apply information to new or unfamiliar situations

Assessed by :1. Calculation2. Similarities and Differences3. Conceptual Series completion4. Social comprehension

Related cortical functions Apraxia Right-Left disorientation Acalculia Agraphia Finger Agnosia Visual agnosia Geographic disorientation

Gerstmann’s

Syndrome

APRAXIA

Loss of ability to carry out skilled movement despite adequate

understanding of task and normal motor power

Ideomotor apraxia Separation of idea of movement from execution• Dominant hemisphere lesion• Unable to carry out commands:

• Buccofacial apraxia: “Show me how to blow out a match” ; “drink through a straw” –

• Limb apraxia: “flipping a coin”, “saluting”, “kicking a ball”

• Truncal apraxia: “stand like a boxer”

Task: fail in command imitating real object

Apraxia Ideomotor

Ideational apraxia Inability to carry out a sequence of movements Higher order of complex motor planning than

ideomotor apraxia Difficulty in manipulating real object Sometimes show object agnosia: e.g. striking

candle to match box Bilateral diffuse cortex lesions especially parietal

cortexTask: “ folding a letter, placing it in an envelope, sealing

it, and placing a stamp on the envelop”

Other apraxias

3. Constructional apraxia and dressing apraxia (Non

dominant parietal disease)

4. Gait apraxia (Frontal lobe/anterior corpus callosum

disease)

5. Occulomotor apraxia (Parieto-occipital disease)

DISCONNECTION PATHWAY1. INTRAHEMISPHERIC

• Linking part of the same hemisphere

2. INTERHEMISPHERE • Corpus callosum link related parts of the two

hemisphere

Intrahemisphere Dysconnection Syndrome

Lesion of the arcuate fasciculus

Fluent dysphasia speech good comprehension,

poor repetitionBroca’s speech area

Wernicke’s speech area

CONDUCTION APHASIA

Lesion beetween the primary auditory cortex (Heschl’s gyrus) and auditory association cortex)

Impaired comprehension of spoken word, self initiated is normal

Patient seems deaf but audiometry is normal

Intrahemisphere Dysconnection Syndrome

PURE WORD DEAFNESS

No connection between the two hemisphere

Failure to name an object presented visually or by touch to the non-dominant hemisphere

INTERHEMISPHERE DISCONNECTION SYNDROME

AGENESIS OF THE CORPUS CALLOSUM

Involves the links between left and right association motor cortices

Right brachiofacial weakness and apraxia of tongue, lip and left limb movements

Premotor motor cortex Broca’s area

Interhemisphere Dysconnection Syndrome

BUCCAL LINGUAL and SYMPATHETIC APRAXIA

INTERHEMISPHERE DISCONNECTION SYNDROME

Lesion of the anterior corpus callosum

Apraxia of the left sided limb move-ment

LEFT SIDE APRAXIA

Lesion of the posterior corpus callosum and dominat occipital lobe (primary visual area)

Inability to read, to name colours, to copy writing and the ability to identify colours Inability to read letter (literal alexia) Inability to read word (verbal alexia)

INTERHEMISPHERE DISCONNECTION SYNDROME

ALEXIA WITHOUT AGRAPHIAPURE WORD BLINDNESS

Alexia without agraphia

Pure alexia Hemi alexia