Sbcm Cerebrum

7/21/2019 Sbcm Cerebrum

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CEREBRUM

Ariel Jose U Ampil, MD

Internist – Diabetologist



Cerebrum

• Composed of two hemispheres, oined b! masses of "ommissural#bers

• $he longitudinal #ssure in"ompletel!separates the two hemispheres

• $he fal% "erbri lies within thelongitudinal #ssure



Cerebrum

• &ra! matter ' surfa"e of the "erebral"orte%

• (hite matter ' beneath the gra! matter

• Basal ganglia ' nu"lear masses beneathwhite matter

• &!rus ' "on)oluted surfa"e of the "orte%

• *ul"us ' spa"e separating the g!ri• +issure ' deep sul"us



Classi#"ation of the CerebralCorte%

• eo"orte%

• Meso"orte%

•

Allo"orte%



eo"orte%

• Also -nown as the iso"orte%

• Comprises ./0 of the "orte%

•

Composed of 1 la!ers234 Mole"ular 5ple%iform6 la!er

74 E%ternal granular la!er

84 E%ternal p!ramidal la!er94 Internal granular la!er

:4 Internal p!ramidal la!er

14 Multiform 5pol!morphi"6 la!er



Meso"orte%

• ;ippo"ampal g!rus

• Cingulate g!rus



Allo"orte%

• 3/0 of the "orte%

• Composed of2

–

<aleo"orte%2 olfa"tor! "orte% – Ar"hi"orte%2 hippo"ampus, dentate

g!rus



=obes of the Cerebrum

• Anatomi" lobes

– +rontal

– <arietal

– >""ipital

– $emporal

• *!ntheti" lobes

– Insular

– =imbi"



+rontal =obe

• =argest lobe

• 3?8 of hemispher@s surfa"e

•

Rostral to the "entral sul"us• *uperior to the lateral #ssure



Anatomi" <arts of the+rontal =obe

• <re"entral g!rus

• <re"entral sul"us

•

*uperior frontal g!rus• *uperior frontal sul"us

• Middle frontal g!rus

• Inferior frontal sul"us• Inferior frontal g!rus



+un"tional <arts of the +rontal=obe

• <rimar! motor "orte%

• <remotor "orte%

•

<refrontal "orte%• Bro"a@s spee"h area



euros!philiti" +rontal =obeAtroph!

• =a"- of a general sense ofresponsibilit!

• *loppiness in habits

• ulgar spee"h

• Clownish beha)ior



<re"entral &!rus

• Brodmann area 9• <rimar! motor area

• 3?8 of "orti"ospinal tra"t arises from

here• +un"tion2 motor "orte% 5"ontralateral

mo)ement of fa"e, arm, leg and trun-6

• Motor humun"ulus

• =esion2 – Monoplegia or hemiplegia

– Initiall! a""id paral!sis

– Babins-i ree%



<refrontal g!rus

• Brodmann area 1

• *upplemental motor area

• Rostral to pre"entral g!rus

• 3?8 of "orti"ospinal tra"t originates fromhere

• +un"tion2

– Contralateral turning of head and e!es

– Assumption of posture

– Comple% patterned mo)ements

–

Infreuent rapid in"oordinate mo)ements



<refrontal g!rus

• =esion2

– <aral!sis of the head and e!e mo)ementto the opposite side 5head and e!es turn

towardF the diseased hemisphere6 – *pasti"it!

– In"reased tendon ree% added to

primar! motor lesion



+rontal e!e#eld

• Brodmann area G

• =o"ated in the "ausal Hone of themiddle frontal g!rus

• *timulation leads to "onugatede)iation of the e!es to the other side

• =esion results in di"ult! in )oluntar!mo)ement of the e!es to the oppositeside



<refontal "orte%

• Brodmann areas .37

• <refrontal area

• =ies rostral to the premotor area andfrontal e!e#eld

• ;as "onne"tions with dorsomedialnu"leus of thalamus, h!pothalamus,

limbi" s!stem, anterior temporal lobeand asso"iation areas of parietal ando""ipital lobes



<refontal "orte%

• +un"tion2 – <ersonalit! – Abstra"t thin-ing –

Mature udgement – +oresight – $a"tfulness – *elf"ontrol –

Initiati)e – *o"ialiHationF of "ertain autonomi"

fun"tions and emotions – Monitor "orti"al plan of beha)ior



<refontal "orte%

• Bilateral ae"tation results in2

– (itHelsu"ht ' inappropriate o"ularit!

– A-ineti" mutism ' se)ere loss ofinitiati)e with disinterest and un"on"ern

– <rimiti)e ree%es 5e4g4 grasp ree%6

– +rontal ata%ia ' disurban"e in gait

– <aratonia ' resistan"e of passi)emo)ements of limbs



<ara"entral lobule

• <re and post "entral g!ri on the medialsurfa"e

• Anteriorl! bounded b! para"entral sul"us

• <osterior border is the marginal bran"h ofthe "ingulate sul"us

• +un"tion2

–

Corti"al inhibition of bladder and bowel )oiding• =esion2

– In"ontinen"e of urine and fe"es



Inferior +rontal &!rus

• <ars orbitalis

• <ars triangularis

•

<ars oper"ularis



Bro"a@s Area

• Composed of pars triangularis andpars oper"ularis

• Brodmann areas 99 K 9:

• E%pressi)e "enter for spee"h in thedominant hemisphere

•

<atterns of mo)ements for mus"lesprodu"ing spee"h

• Control motor spee"h



Bro"a@s Area

• =esion in the dominant hemisphereprodu"es Bro"a@s 5motor ore%pressi)e6 d!sphasia



<arietal =obe

• <osterior to the "entral sul"us

• Rostral to the parietoo""ipital g!rus

• Composed of 2

– <ost"entral g!rus 5Brodmann areas 8, 3, 76

– *e"ondar! somestheti" area

– *uperior parietal lobule

– Inferior parietal lobule

– <arietal oper"ulum



<ost"entral &!rus

• &ranular "orte% ? sensor! "orte% ?primar somestheti" area

• Brodmann areas 8, 3, 7

• Corti"al regions where impulses"on"erned with ta"tile and -inestheti"sense from super#"ial and deep

re"eptors "on)erge and aresomatopi"all! represented 5sensor!humun"ulus6



<ost"entral &!rus

• +un"tions to re"ei)e aerent pathwa!s forappre"iation of posture, tou"h and passi)emo)ements

• =esions result in2 – "ontralateral impairment of tou"h, pressure and

proprio"eption

– Disturbed postural and passi)e sensation

– Disturbed lo"aliHation of tou"h with loss of two

point dis"rimination – Astereognosis ' impaired appre"iation of siHe,

shape, te%ture and weight

– <er"eptual ri)alr! ' sensor! inattention



*e"ondar! *omestheti"Area

• <osterior to BA 8, 3, 7

• =ies along superior border of the*!l)ian #ssure

• =esions result in impaired painsensation



*uperior <arietal =obule

• *eparated from the inferior parietallobule b! the intraparietal sul"us

• Brodmann areas : K L



Inferior <arietal =obule

• Composed of two g!ri2

– *upramarginal g!rus

– Angular g!rus

• Corti"al asso"iation areas

• Mnemoni" "onstallations forunderstanding and interpretingsensor! signals



*upramarginal &!rus

• Brodmann area 9/

• +un"tions in understanding andinterpretting sensor! signals

• =esions in dominant hemisphere resultin ta"tile and proprio"epti)e agnosia

• =esions in nondominant hemispheres

result in "onfusion leftrightdis"rimination, bod! image disturban"eand apra%ia



Angular &!rus

• *urround as"ending terminal part ofsuperior temporal sul"us

• Brodmann area 8.

• Asso"iation "orte% whi"h has"onne"tions with somestheti", )isualand auditor! asso"iation areas

• =esions in dominant hemisphereresult in ale%ia 5inabilit! to read6 andagraphia 5inabilit! to write6



isual <athwa! of the<arietal =obe

• >pti" radiation

• (here #bers of the opti" radiation5lower )isual #eld6 pass through theparietal lobe

• Results in lower homon!mousuadrantanopsia



<arietal >per"ulum

• =o"ated in the roof of the lateral#ssure

• Brodmann are 98

• fun"tions for taste sensibilit!



*ensor! or IdeationalF *pee"hArea

• *upramarginal g!rus

• Angular g!rus



ondominant parietal lobe

Important for )isual andproprio"epti)e s-ills – to "onstru"tshapes

• +un"tions in bod! image andawareness of e%ternal en)ironment



ondominant <arietal =obe

• isual and proprio"epti)e s-ills – to"onstru"t shapes

• +un"tions in2

– bod! image and awareness of e%ternalen)ironment

– isual and proprio"epti)e s-ills

– *patial orientation



ondominant <arietal =obe

• =esions result in2

– Asomatognosia

– Anosognosia 5denial of wea-ness6

– Dressing apra%ia

– &eographi"al apra%ia

– Contru"tional apra%ia unawae of

opposite limb 5left side6



Dominant <arietal =obe

• Important for appre"iation ofnumbers and "al"ulation

• =esion results in2

– &ertsmann@s s!ndrome

• Confusion of right and left limbs

• +inger agnosia 5di"ult! in distinguishing

#nger from hand6• A"a"l"ulia

• Agraphia



$emporal =obe

• *uperior temporal g!rus

– <rimar! auditor! "orte%

– *e"ondar! auditor! "orte%

• *uperior temporal sul"us

• Middle temporal g!rus

•

Inferior temporal sul"us• Inferior temporal g!rus



*uperior $emporal &!rus

• <arallel with the lateral #ssure

• =esions present with auditor!hallu"inations 5b! diseases li-e"omple% partial sieHures6 and )ertigo



<rimar! Auditor! Corte%

• =o"ated on the trans)erse g!ri of ;es"hl5se)eral short obliue "on)olutions onthe inner ban- of the lateral sul"us6

•

Upper surfa"e of superior temporalg!rus

• Brodmann areas 93, 97

• +un"tions2 – Dominant hemisphere ' hearing language

– ondominant hemisphere ' hearing sound,rh!thm and musi" lab!rinthine fun"tion



<rimar! Auditor! Corte%

• =esions results in2

– Corti"al deafness

– Dominant hemisphere ' di"ult! hearing

spo-en words – ondominant hemisphere ' di"ult!

appre"iating sound, rh!thm and musi"5amusia6

– Unilateral lesions ha)e little ee"ts onhearing 5signi#"ant auditor! defe"ts in)ol)eeither C G or its entr! in the brainstem6



*e"ondar! Auditor! Corte%

• Auditor! asso"iational area

• Brodmann area 77

•

+un"tion2 dominant hemisphere 'language "omprehension

• =esion2 (erni"-e@s aphasia 5re"epti)e? sensor! aphasia6



Middle and $emporal &!rus

• In)ol)ed in memor! and learning

• =esions result in disturban"e inmemor! and learning

i l h f h l



isual <athwa! of the $emporal=obe

• >pti" radiation

• (here #bers of the opti" radiation5upper )isual #eld6 pass through thetemporal lobe

• Results in upper homon!mousuadrantanopsia



<rimar! >lfa"tor! Area

• Composed of prep!riformisF andNperiam!gdaloidF area

• +or the sense of smell



>""ipital =obe

• Abo)e tentorium "erebelli

• *eparated from parietal lobe theparietoo""ipital sul"us

• Consists of2

– =ateral o""ipital g!ri

– Cuneus

– Cal"arine sul"us

– =ingual g!rus



>""ipital =obe

• In)ol)ed in )isual per"eption

• Corti"al lesion ' homon!moushemianopsia

• >""ipital pole onl! ' "entralhemianopsia in)ol)ing the ma"ula

• E%tensi)e damage of the striate "orte%

results in Anton@s s!ndrome – Denial of "orti"al blindness

– Inta"t pupillar! light ree%



<rimar! isual Corte%

•=o"ated along the ban-s of the "al"arinesul"us – Cal"arine sul"us oins parietoo""ipital

sul"us rostrall! in a O shaped formation

• Brodmann area 3L• <er"eption of "ontralateral half of the

)isual #eld

•

Re"ie)es impulses from temporal half ofipsilateral retina and nasal half of"ontralateral retina

• =esion results in "orti"al blindness in the

"ontralateral )isual #eld



*e"ondar! isual Area

• =ies ada"ent and anterior to BA 3L

• Brodmann area 3G, 3.

•

In)ol)ed in )isual per"eption and)isual ree%es 5i4e4 )isual #%ation6

• =esions results in )isual agnosia5di"ult! in re"ogniHing andidentif!ing obe"ts )isuall!6

I f i * f f C b



Inferior *urfa"e of Cerebrum• >lfa"tor! sul"us separates lateral orbital g!ri from

medial g!rus re"tus• >lfa"tor! bulb and tra"t inferior to the olfa"tor!

sul"us

• Inferior surfa"e lies in the middle fossa of the s-ull,re)eals part of the inferior temporal g!rus, the broad

o""ipitotemporal g!rus and the parahippo"ampalg!rus

• Un"us – Most medial protrusion of the parahippo"ampal g!rus

–

*eparated from the o""ipitotemporal g!rus b! the"ollateral sul"us

• <rimar! olfa"tor! "orte% – Rostral part of parahippo"ampal g!rus

– Un"us

– =ateral olfa"tor! stria





=imbi" *!stem

• is"eral brain

• In"ludes a di)erse group of medialand basal telen"ephali" stru"tures,

whi"h represent those regions of the"erebral "orte% ha)ing the most dire"t"onne"tions with the h!pothalamus

• Defensi)e rea"tions su"h as fear orrage are integrated diusel!



=imbi" *!stem

• >ther stru"tures "losel! related tothe limbi" s!stem

– <osterior orbitofrontal "orte%

– Anterior temporal "orte%

– Anterior nu"lear group of the thalamus

– ;!pothalamus

– *eptal region

– Midline nu"lei



aferent structure eferent unction

Cingulate g!ruseo"orte%*eptum

;ippo"ampalformation

+orni%<re"ommisural#bers

<ost"ommosural #bers

Memor! andlearningIntegrating

sensor! input

>lfa"tor! bulbRostralh!pothalamus

Inferiortemporal lobe>rbitofrontal"orte%Brainstemreti"ular

formation

am!gdala *tria terminalisentralam!gdalofugal

proe"tion

*timulationleads to ragerea"tion

=esions resultsin do"ilit!

Cingulate g!rus <arahippo"ampal g!rus

;ippo"ampus

Anterior nu"learnu"lear group

of the thalamusAsso"iation

Cingulate g!rus Cingulum

entorhinal area

of theparahippo"amp



<apeH Cir"uit

• <arts of limbi" s!stem anddien"ephalon

• Con"erned with emotion

• ;ippo"ampal formation 5forni%6

mammillar! bod! 5mammillothalami" tra"t6 anterior

nu"lear group of the thalamus "ingulate g!rus



Plu)er – Bu"! *!ndrome

• Bilateral lesions destro!ing the am!gdalaand hipppo"ampus in male mon-e!s

• Manifestations –

<s!"hi" blindness – ;!permetamorphosis

– ;!peroralit!

– ;!perse%ualit! and loss of se%ual preferen"e

– Re)ersal of indi)idual beha)ioral patterns – Mar-ed absen"e of emotional response

– =oss of fa"ial e%pression and )o"al protests



>ther "lini"al manifestations

• Bilateral damage to the medialtemporal lobes results in anterogradeamnesia, whi"h is a profound loss of

the abilit! to a"uire new information• Porsa-o@s ps!"hosis also present

with anterograde amnesia, ae"ted

b! lesions in the mammillar! bodiesand the dorsomedial nu"leus of thethalamus



$han- !ou )er!

mu"hfor !our -ind

attentionQ

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Sbcm Cerebrum