Neuropsihologia clinică

Prof. Ion V. Moldovanu

Catedra de Neurologie

Universitatea de Medicin i Farmacie N.Testemitanu

Neuropsihologia clinic

Neuropsihologie: ntrebri majore

1. Afazia. Definiie. Deosebirea de disartrie

2. Agnozia. Tipurile de agnozie. Prosopagnozia

3. Definiia apraxiei i formele ei clinice

4. Sindromul lobului frontal

5. Sensory Neglect Syndrome. Definiie

6. Alte manifestri clinice n leziunea lobului parietal

7. Leziunea lobului temporal - manifetri clinice

8. Lobul occipital - semnele de leziune

9. Demena. Definiie.

10. Maladia Alzheimer i demena vascular

Predecesorii Neuropsihologiei:

Frenologia

Disciplin care se ocup de funciile mentale superioare n cadrul raportului lor cu structurile cerebrale* (Hecaen H. 1973 )

nelegerea relaiilor dintre creier i

comportament

funcionarea creierului ce produce o varietete de

aciuni proprii fiinei umane

Neuropsihologia

Paul Pierre Broca (1824 - 1880)

Zona Broca

In 1861 Broca descrie cazul unui pacient, care

a pierdut capacitatea de vorbire (putea doar s emit zgomote i sunete neinteligibile)

La necropsie s-a constatat o leziune n zona cortexului frontal al emisferei stngi.

Actualmente, aceast deteriorare este referit zonei Broca ce determin afazia Broca: vorbile lent, nceat cu o structur gramatical foarte simpl

Celebru prin lucrarea sa despre afazia

sensorial (1874) i poliomielita hemoragic superioar, ambele i poart numele

Carte despre leziunea capsulei interne

Manual de neurologie.

DR. CARL WERNICKE

(1848-1904)

Asimetria funcional a emisferilor cerebrale

Asimetria funcional a emisferilor

cerebrale Dou structuri simetrice = aceleai funcii? (ochi, urechi,rinichi, plmni)

Broca 1861,Wernicke 1874 i conceptul emisferei dominante

Curentul localizator (creierul un mozaic de centre funcionale)

Curentul globalist (creierul o mas omogen cu excepia ariilor motorii i

senzoriale primare)

A localiza leziunea care duce la pierderea vorbirii i a localiza vorbirea sunt dou lucruri diferite

(Jackson,1864)


cerebrale (II)

Comisurotomia, creier

secionat (split-brain)

Conceptul de asimetrie

funcional


cerebrale (II)

Comisurotomia, creier secionat (split-brain)

Conceptul de asimetrie funcional

Conflictul interemisferic

(intermanual)

analiza modificrilor capacitilor intelectuale de percepie limbaj memorie personalitate

aprute n urma unei leziuni cerebrale



Zona Broca

In 1861 Broca descrie cazul unui pacient, care

a pierdut capacitatea de vorbire (putea doar s emit zgomote i sunete neinteligibile)

La necropsie s-a constatat o leziune n zona cortexului frontal al emisferei stngi.

Actualmente, aceast deteriorare este referit zonei Broca ce determin afazia Broca: vorbire lent, nceat cu o structur gramatical foarte simpl

Celebru prin lucrarea sa despre afazia

sensorial (1874) i poliomielita hemoragic superioar, ambele i poart numele

Carte despre leziunea capsulei interne

Manual de neurologie.

DR. CARL WERNICKE

(1848-1904)

AFAZIA Afazia este o alterare achiziionat a

limbajului n rezultatul unei leziuni cerebrale

Nu se consider afazie: Deficienele de nsuire ale limbajului leziuni precoce

insuf. dezvoltrii creierului autizm

surditate

Tulburri psihice

Atingere sensorial

Paralizia organelor efectorii

disfonie

dizartrie

Afazia motorie (Broca)

Afazia Broca este o varietate a afaziilor non fluente, care se caracterizeaz prin reducerea discursului. (N =90 c/min)

Vorbirea e:

rar, constnd esenial din nume, verbe tranzitive i adjective eseniale;

cuvintele scurte sunt omise, dnd limbajului un stil telegrafic, agramat.

eforturile bolnavului pentru a vorbi i mimica sa denot prezena contiinei erorilor cu reacii de enervare sau angoas frecvente.

Discursul e:

aspontan

ncetinit monoton

silabisit

laconic

emis cu efort ( disprozodie )

Afazia motorie (Broca)

Comprehensiunea oral ( nelegerea limbajului adresat pacientului ) este relativ pstrat

Denumirea la ordin a obiectelor i imaginilor e corect i n absena apraxiei pacienii execut comenzile simple

Cauza:

consecina unei leziuni ischemice, interesnd emisfera stng i se asociaz cu o hemiplegie dreapt cu sau fr hemianestezie, apraxie bucco-facial, eventual cu apraxie ideo-motorie.

Fluena verbal

Fluen categorial* : denumiri de animale 2 min

Fluena fonematic: Cuvinte comune ce ncep cu litera m

Scorul < 20 pentru denumiri de animale (16)

< 15 pentru cuvinte comune (10)

Variaz n funcie de nivelul socio-cultural

Afazia senzorial (Wernicke)

Afazia Wernicke- afazie fluent

(producie verbal abundent i incoerent).

Limbajul este :

normal articulat

spontan

logoreic (incontinuu)

parafazii, neologisme asemantice

test.cuvintelor decupate:

/iepurii/ / vneaz/ /vntorul/

Afazia senzorial (Wernicke) Coninutul discursului este, ca regul, lipsit de sens

neneles pentru persoanele nconjurtoare

Anosognozia

Comprehensiunea pacientului e perturbat

Afazia Wernicke se manifest n absena hemiplegiei. O hemianopsie lateral omonim pe dreapta se asociaz frecvent

Leziunile responsabile intereseaz cortexul auditiv asociativ

(partea posterioar a primei circumvoluii temporale) i lobul parietal inferior ( gyrus supramarginal i angular ).

AGNOZIA

Agnozia deficit de recunoatere

a stimulilor externi i interni

Absena tulburrilor

de percepie

de limbaj

psihice

AGNOZIA

AGNOZIA Agnozii vizuale

Agnozia vizual pentru obiecte i imagini este

incapacitatea de a identifica vizual un obiect sau reprezentarea sa grafic

(n absena tulburrilor funciilor vizuale elementare sau a capacitilor intelectuale. Obiectul nu este recunoscut vizual, dar e identificat palpator)

Agnozia culorilor - imposibilitatea de a numi culorile atunci, cnd ele sunt corect aplicate obiectelor.

Agnozia facial (prozopagnozia)- imposibilitatea recunoaterii feelor persoanelor chiar apropiate.

(Identificarea poate deveni posibil la auzirea vocii).

Afectarea lobului occipital e cauza manifestrii diferitor forme de agnozii vizuale.

Prozopagnozia Agnozii vizuale

Agnozia facial (prozopagnozia)- imposibilitatea recunoaterii feelor persoanelor chiar apropiate.

Identificarea poate deveni posibil la auzirea vocii.

AGNOZIA

Agnozii auditive

Surditatea cortical sau agnozia auditiv (rar). Pacientul e

incapabil de a identifica sunetele, fie c e vorba de zgomote familiare, muzic sau mesaj verbal

Leziunile responsabile sunt bilaterale cu afectarea zonei Heschl sau a relaiilor ei cu corpul geniculat intern

Surditatea verbal constituie un deficit selectiv de identificare a coninutului mesajului verbal. Ea e, ca regul, asociat cu afazia Wernicke

Amuzia desemneaz incapacitatea de a identifica melodiile, determinat de afectarea lobului temporal drept

AGNOZIA Stereognozia: cunoaterea tactil

a obiectelor

Astereognozia este incapacitatea de a

identifica un obiect pe cale tactil n absena oricrei informaii vizuale sau auditive.

Astereognozia e frecvent n leziunile cortexului parietal, fiind, ca regul, asociat cu tulburri importante ale sensibilitii de localizare, de poziie i discriminare ale stimulilor tactili.

AGNOZIA Cunoaterea spaiului extra- i

intracorporal

Sensory Neglect (Neglijarea spaial unilateral -NSU) deficit lateralizat a cunoaterii spaiale,condiionat

de leziunea lobului parietal, care se caracterizeaz prin imposibilitatea de a descrie verbal, de a rspunde i de a se orienta n raport cu stimulrile de partea controlateral leziunii

Cunoaterea spaiului extra- i intracorporal

Bolnavii ignor de obicei hemispaiul

stng: un dirijor ignor muzicanii din

orchestr plasai la stnga sa, pacienii i rad doar hemifaa dreapt,

etc.

tulburri de citire, cci nu cerceteaz jumtatea stng a paginii.

Pentru a cerceta NSU se utilizeaz copierea unui desen. Pacientul cu NSU va uita jumtatea stng a figurii.

Sensory Neglect

(Neglijarea spaial unilateral -NSU)

lldfkdlkdlkdflkdsgk

,mv.,mv.mv.,mv.m

D,..,fv,.vn dfn

dd.Mds Sensory Neglect

(Neglijarea spaial unilateral -NSU)

.msdmsd,.m

lsdsldmflsdmfsdm

Sdms.dmd,mds.m

sdmsdm.sm.dm

Sd,fmas,.mf.d

fkslfk

AGNOZIA Anozognoziile hemiplegiei (sindromul Anton- Babinski)

dispariia mai mult sau mai puin total a hemicorpului stng din cmpul contiinei. E o form major de hemiasomatognozie. Pacientul refuz existena deficitului su motor. Aparine preponderent leziunilor vasculare ale lobului parietal n perioada lor iniial

Autotopagnozia - pierderea capacitii de a indica la comand

oral prile propriului corp Sindromul Gerstmann (tetrad simptomatic): agnozie digital, agrafie pur, dezorientare dreapta-stnga acalculie.

APRAXIA Apraxia perturbare ale micrilor

voluntare achiziionate

Nu sunt atribuite:

- tulburrilor motorii primare

- deficitului de nelegere

leziunii frontale sau parietale

ACTIVITI GESTUALE: APRAXIILE

Principalele aspecte ale apraxiei

Apraxia dinamic

incapacitatea de a supune aciunea unui plan, evideniat prin testele de apraxie: incapacitatea de a reproduce un grafism regulat alternant

Ansamblul acestor tulburri indic o perturbare a controlului exercitat de lobul frontal asupra

gestului. Apraxia dinamic e sever n cadrul leziunilor frontale bilaterale.

ACTIVITI GESTUALE: APRAXIILE

Apraxia ideo-motrice (gestual i de mimare)*

Pacientul e incapabil de a executa la ordin salutul militar sau de a mima gestul utilizrii unui ciocan.

Executarea e perfect atunci, cnd pacientului i se propune s utilizeze real un obiect (de exemplu, ciocanul) n loc s-i mimeze ntrebuinarea

Ca regul, apraxia ideo-motrice e bilateral i rezult din leziunea lobului parietal stng.

Apraxia ideatorie

se manifest n cadrul utilizrii obiectelor n aciuni simple: utilizarea unui creion, a aprinde un chibrite sau n aciuni mai complexe: a face un plic, a aprinde o lumnare

Apraxia ideatorie e bilateral, ca regul asociat cu o important apraxie ideo-motrice ca consecin a unei leziuni vaste a lobului parietal stng.

Apraxia constructiv

Perturbri de utilizare a relaiilor spaiale. Apraxia constructiv rezult dintr-o leziune parietal stng sau dreapt sau a

corpului calos. Ea e facilitat prin asocierea unei leziuni frontale.

Examenul apraxiilor

Apraxia reflexiv (imitaie) :

Inel dublu

Aripi defluture

Mnile ncruciate

Mnile ncruciate (invers)

Ideomotorie(reproducerea gesturilor cunoscute)

Salut militar

Adio

A trimite un srut

A curi o banan

Constructivitatea grafic

Copierea desenelor

Stephen

Haking

Semiologia clinic neuropsihologic n cadrul leziunilor diverselor structui

cerebrale

Lobul frontal

Lobul frontal Zona prefrontal (funciile cognitive superioare ) planificare

organizare

soluionarea problemelor

atenie selectiv

personalitatea

o varietate de " funcii cognitive superioare " incluznd comportamentul i emoiile

.

Zona premotorie

modificarea micrilor

Sindromul lobului frontal

(fenomene neuropsihologice)

Apraxia mersului (aria premotorie)

Lips se iniiativ Mersul n foarfece Reacii de magnet (magnet apraxia Denny Brown) Reflexul de prehensiune i de tatonare

Personalitate frontal (cortexul prefrontal) Apatie i inerie motorie Moria -comportament dezinhibat,pueril

-schimbari de dispaziie -tendin spre calambururi -megalomanie

-hipersexualitate, bulimie

Perseveraii motorii

Comportament de utilizare i imitare

Tulburri de atenie

Afazia Broca

Sindromul Diogene

Sindromul lobului parietal


Epilepsie somato - senzitiv parial

Hemianestezie parietal

Amiotrofie parietal

Extincia (neatenie senzitiv)

Asteriognozie

Apraxie

Hemiasomatognozie

sindromul Alice n ara minunilor hemi-depersonalizare (parc n-ar exista jumtate de corp)

Sindrom Anton- Babibnski ( anozognozia hemiplegiei)

Sindromul Gerstman agnozie digital agrafie pur dezorientare dreapta stnga acalculie

Negligen (agnozie) spaial unilateral

Sindromul lobului temporal


Tulburri de audiie

Sunete nedifereniate (zgomote simple)

Halucinaii auditive bine organizate (cuvinte ,cntece,clopot)

Tulburri olfactive (gyrusul hipocampic)

Halucinaii olfactive (benzin, fum, usturoi)

Tulburri gustative

Halucinaii gustative (n cadrul crizelor uncinate)

Epilepsie temporal somatosenzorial

(crize gustative,olfactive,auditive,vertiginoase, vegetative)

Tulburri de comportament (sndr. Kluver - Bcy )

(tendine orle, placiditate, comp.sexual anormal, tend. de a fi distrat )

Leziuni bilaterale

Amnezie global (afectarea hipocampului bilateral)

Agnozie auditiv

Agnozie vizual

sndr. Kluver Bcy

Sindromul lobului occipital


Iluzii i halucinaii vizuale

scotom

iIuzii

halucinaii

Cecitate cortical (cecitate psihic) [leziune bilateral+abs. tulb vederii periferice]

refl. foto-pupilar N

motilitate ocular pstrat

reflex de ameninare absent

Amnezie i dezorientare n spaiu (amnezie occipital)

pierderea memoriei topogrqafice (analogie cu prozopagnozia)

Prozopagnozia

(nu poate fi explicat printr-o deteriorare intelectual i mnezic global i nici printr-o tulburare perceptual )

Sndr Balint

paralizia psihic a privirii

ataxia optic

tulburare atenional (simultagnozia)

MEMORIA

Memoria este capacitatea organismelor vii de

a obine, de a reine i de a utiliza un ansamblu de

cunotine sau de informaii

Procesul mnezic (Memoria)

CODIFICAREA

STOCAREA (procesul de memorizare)

RECUPERAREA

Alzheimer

mbtrnire Depresie

Depresie

mbtrnire

SEMIOLOGIA AMNEZIILOR

Amnezia anterograd imposibilitatea sau diminuarea capacitii de a reine informaii actuale, noi, aprute dup instalarea tulburrilor mnezice

Amnezia retrograd- corespunde imposibilitii evocrii amintirilor dobndite nainte de instalarea acut sau progresiv a tulburrilor de memorie

Amnezia lacunar - desemneaz o perioad de via a subiectului, care n-a lsat nici o urm n memoria sa.

Confabulaiile - rspunsuri verbale eronate referitoare la rememorarea amintirilor recente sau din trecut

SEMIOLOGIA AMNEZIILOR

Sindromul Korsakoff i amneziile axiale - tulburare sever a memoriei cu confabulaii i recunoateri false asociate cu polineuropatie consecutiv unei carene de tiamin la alcoolici denutrii. Asemenea tulburri mnezice se mai constat la subieci cu afeciuni bilaterale ale structurilor limbice sau ale regiunii diencefalice.

(exemplu clinic)

Amneziile lacunare- ca regul, sunt consecina unei pierderi a contiinei sau a unei perioade de confuzie mental: pe parcursul acestei perioade nici o tras mnezic n-a fost nregistrat. Exist o ntrerupere n biografia bolnavului

Ictusul amnezic- se instaleaz brusc la subiecii de 50-70 de ani fr cauz declanatoare precis, dureaz 6-8 ore i nu las alte sechele dect o amnezie lacunar

Amneziile globale se nregistreaz n cadrul diferitelor forme de demen, atunci cnd tulburrile mnezice nu sunt dect un aspect al unei deteriorri mai vaste a funciilor intelectuale.

Sindromul demenial : DSM IV

Apariia diverselor deficite cognitive multiple

Altrerea memoriei pe termen scurt

Una sau mai multe tulburri cognitive ce urmeaz:

Afazie, apraxie, agnozie, tulb. funciilor executive

Alterri importante a funcionrii sociale

Declin n comparaie cu nivelul de funcionare anterior

Consecine patologice organice

Necondiionate de o stare confuziunal

Maladia Alzheimer :

definiie

Asocieri :

un sindrom demenial

Absena altor cauze

diagnosticul de prezumie, de eliminare

Maladia Alzheimer probabil sau posibil

Sunt oare leziuni cerebrale

caracteristice: DNF(degenerescen neuro-fibrilar), plci neuritice

Caz clinic

MMS Orientation :

Noter 1 point par rponse exact ; 0 si la rponse est inexacte ou en labsence de rponse.

1) En quelle anne sommes-nous ? _____

2) En quelle saison ? _____

3) En quel mois ? _____

4) Quelle est la date ? _____

5) Quel jour de la semaine sommes-nous ? _____

6) Dans quel ville nous trouvons-nous ? _____

7) Quel est le nom du dpartement ? _____

8) Dans quelle rgion sommes nous ? _____

9) Quel est le nom de lhpital (ou adresse du mdecin) ? _____

10) A quel tage sommes-nous ? _____

Mmoire immdiate (apprentissage) :

Nommez trois objets, attendez une seconde entre chaque. Demandez au patient de les rpter tous les trois. Compter 1 point

par mot correctement rpt.

11) Cigare Citron _____

12) Fleur Clef _____

13) Porte Ballon _____

Rpter jusqu ce que les 3 mots soient appris, noter le nombre dessai.

Attention et calcul mental :

Le patient doit soustraire 7 de 100, arrter aprs 5 soustractions. Compter 1 point par soustraction correcte. En cas

derreur, demander tes-vous sr ? et compter 1 point si la rponse est bonne ;

14) 100-7 _____

15) 93-7 _____

16) 86-7 _____

17) 79-7 _____

18) 72-7 _____

Pouvez-vous peler le mot monde lenvers (preuve obligatoire mais non cote).

MMS Mmoire court terme :

Vous souvenez-vous des trois mots que vous avez rpts tout lheure ? Compter 1 point par mot rpt.

19) Cigare Citron _____

20) Fleur Clef _____

21) Porte Ballon _____

Langage :

22) Dnommer un crayon en prsentant lobjet (rponse juste = 1 point) _____

23) Dnommer une montre en prsentant lobjet (rponse juste = 1 point) _____

24) Rptez : Il ny a pas de mais, de si, ni de et. _____

Faire excuter un ordre triple :

25) Prenez ce papier dans la main droite _____

26) Pliez-le en 2 _____

27) Jetez-le par terre. _____

Notez 1 point par item soulign correct.

28) Faites ce qui est marqu fermez les yeux (1 point si lordre est effectu). _____

29) Copiez ce dessin sur une feuille _____

30) Ecrivez-moi une phrase, ce que vous voulez, mais une phrase entire. _____

(compter 1 point pour une phrase comprenant au moins un verbe, un sujet, un complment, smantiquement correcte,

grammaire et orthographe indiffrentes).

Score total sur 30 :

Toutes les cases doivent tre remplies

MMS

Prob cognitiv global Examen de depistare i supraveghere Facil i rapid la utilizare De luat n calcul nivelul socio- cultural

30 - 28 normal sau MCI sau MA n debut 26/24>MMS>20 demen leger 19>MMS>10 demen moderat

Neuropsihologie: ntrebri majore

1. Afazia. Definiie. Deosebirea de disartrie

2. Agnozia. Tipurile de agnozie. Prosopagnozia

3. Definiia apraxiei i formele ei clinice

4. Sindromul lobului frontal

5. Sensory Neglect Syndrome. Definiie

6. Alte manifestri clinice n leziunea lobului parietal

7. Leziunea lobului temporal - manifetri clinice

8. Lobul occipital - semnele de leziune

9. Demena. Definiie.

10. Maladia Alzheimer i demena vascular

MEMORIA.

Memoria (M) este capacitatea organismelor vii de a obine, de a reine i de a utiliza un ansamblu de cunotine sau de informaii.

Memoria pe termen scurt (memoria imediat sau primar) se refer la un sistem, ce menine informaii temporar (de ordinul unui minut), nainte ca aceasta s fie transformat sub o form mai durabil n memoria pe termen lung (memoria secundar). Memoria imediat are o capacitate limitat la 7 cifre sau fenomene prezentate auditiv sau vizual. Fiind efemer, memoria imediat nu poate fi suportul memoriei de lucru (a reine temporar numrul unui telefon), dect ccu preul unui efort de atenie.

Memoria de lung termen se refer la achiziii durabile, accesibile la o reamintire contient (memoria declarativ sau explicit)sau ce in de nsuirea procedurilor tehnice i cognitive (memoria procedural sau implicit). Memoria explicit poate fi explorat prin intermediul ntrebrilor relativ la cunotine didactice i evenimente ale trecutului. Printre aceste achiziii unele se refer la o circumstan definit a vieii subiectului i evocarea lor se produce n context specific (memoria epizodic). Altele aparin fondului cultural i condiiile nsuirii lor au fost uitate (memoria semantic).

DR. CARL WERNICKE

(1848-1904)

Wernicke was born in Tarnovitz, Poland but his family moved to Germany where he received all his education.

Interested in psychiatry, traditionally he studied anatomy initially and neuropathology later. He published a small volume on aphasia which vaulted him into international

fame. In it was precise pathoanatomic analysis paralleling the clinical picture. He is best known for his work on

sensory aphasia and poliomyelitis hemorrhagia superior. Both of these descriptions bear his name. Further, his books on the disorders of the internal capsule and his

textbooks on diseases of the nervous system perpetuate him.

Wernicke's drawing of Motor and Sensory Speech areas

Frontal Lobe Damage

Cognitive Impairments Following Frontal Lobe Damage.

Milner & Petrides (1984) reviewed the effects of frontal lobe damage in humans and concluded that the following behaviours were impaired:

Temporal sequencing: i.e the ability to say which of 2 pictures had been presented most recently.

Shifting of attention: there is an increased tendency to persevere with an action when it is obviously incorrect (perseveration).

Conditional associations: the ability to associate a correct response with a particular stimulus.

Working memory: the ability to maintain a response in memory and then act upon it appropriately.

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Understanding words

When you listen to (or read) words, you are using a part of your brain known as Wernicke's area. It was named after the German doctor Carl Wernicke, who first realised that speaking and understanding words were controlled by different parts of the brain. He described patients who couldn't understand speech. Although they could speak words clearly, they made no sense. They had damage to the left temporal cortex of their brains.

Wernicke's area (arrowed) is needed to understand language.

Keith Johnson, Harvard University

DR. CARL WERNICKE (1848-1904)

Wernicke was born in Tarnovitz, Poland but his family moved to Germany where he received all his education. Interested in psychiatry, traditionally he studied anatomy initially and neuropathology later. He published a small volume on aphasia which vaulted him into international fame. In it was precise pathoanatomic analysis paralleling the clinical picture. He is best known for his work on sensory aphasia and poliomyelitis hemorrhagia superior. Both of these descriptions bear his name. Further, his books on the disorders of the internal capsule and his textbooks on diseases of the nervous system perpetuate him. Wernicke's drawing of Motor and Sensory Speech areas

Petite Biographie : Fils d'un chirurgien des armes impriales, il est n Sainte-Foy-la-Grande le 28 juin 1824. C'est Paris qu'il fera ses tudes de mdecine. Titulaire du Doctorat en avril 1849, il mnera alors de front deux carrires accomplies au prix d'un travail forcen : Chirurgien, chercheur, il participe ce grand mouvement scientifique du XIXme Sicle. Reconnu par ses pairs, il cumulera alors les charges, les honneurs. Membre de l'Acadmie de Mdecine en 1866, il est le fondateur de l'Anthropologie moderne, vaste science volutive. Il crera en 1868, le Muse et le laboratoire d'Anthropologie de l'cole des Hautes-tudes Paris. Mettant ses pas dans ceux de Pierre Gratiolet, son an (1815-1865) et concitoyen, il prononcera son loge funbre trs touchant (cf. Archives Municipales de Sainte-Foy) et comme lui ses travaux sur les localisations crbrales, illustrent le savant (voir croquis).

Rpublicain ardent, il est lu snateur en 1880. Courte vie politique hlas, car il dcde le 8 juillet 1880 de faon foudroyante. La science perd alors un Grand Homme.

______________________

Dfinition : Zone et Aphasie de Broca, Il existe une zone dans le lobe frontal de l'hmisphre gauche, appele la zone de Broca.

Elle est situe ct de la rgion qui contrle le mouvement de certains muscles faciaux: ceux de la langue, des mchoires et de la gorge. Si cette zone est dtruite, des difficults mettre des sons spcifiques en rsulteront. On est alors dans l'incapacit d'effectuer de faon adquate, les mouvements de la langue ou des muscles faciaux pour produire des mots. La personne est encore capable de lire et de comprendre les mots mais prouve de la difficult crire (la formation de lettres ou de mots ne se fait pas sur les lignes). Ce problme est appel aphasie de Broca.

Sainte-Foy-la-Grande : La Place Broca et sa statue avant qu'elle ne soit dboulonne par les allemands durant la guerre.

La ville bastide de Sainte-Foy-

la-Grande, porte du Prigord, est btie en bordure de la Dordogne, aux confins de trois

dpartements: la Gironde, la Dordogne et le Lot-et-Garonne.

Elle occupe une plaine

verdoyante entoure de coteaux, premiers versants o dj s'tirent les ceps de vigne...


Petite Biographie : Fils d'un chirurgien des armes impriales, il est n Sainte-Foy-la-Grande le 28 juin 1824. C'est Paris qu'il fera ses tudes de mdecine. Titulaire du Doctorat en avril 1849, il mnera alors de front deux carrires accomplies au prix d'un travail forcen : Chirurgien, chercheur, il participe ce grand mouvement scientifique du XIXme Sicle. Reconnu par ses pairs, il cumulera alors les charges, les honneurs. Membre de l'Acadmie de Mdecine en 1866, il est le fondateur de l'Anthropologie moderne, vaste science volutive. Il crera en 1868, le Muse et le laboratoire d'Anthropologie de l'cole des Hautes-tudes Paris. Mettant ses pas dans ceux de Pierre Gratiolet, son an (1815-1865) et concitoyen, il prononcera son loge funbre trs touchant (cf. Archives Municipales de Sainte-Foy) et comme lui ses travaux sur les localisations crbrales, illustrent le savant (voir croquis).

Rpublicain ardent, il est lu snateur en 1880. Courte vie politique hlas, car il dcde le 8 juillet 1880 de faon foudroyante. La science perd alors un Grand Homme.

Hemispheric Specialization

The two hemispheres of the cerebral cortex are linked by the corpus callosum, through which they communicate and

coordinate. Nevertheless, they appear to have some separate

functions. The right hemisphere of the cortex excels at

nonverbal and spatial tasks, whereas the left hemisphere is

usually more dominant in verbal tasks such as speaking and

writing. The right hemisphere controls the left side of the

body, and the left hemisphere controls the right side.

When split-brain patients stare at the "X" in the center of the

screen, visual information projected on the right side of the

screen goes to the patient's left hemisphere, which controls

language. When asked what they see, patients can reply

correctly.

When split-brain patients stare at the "X" in the center of the screen, visual

information projected on the left side of the screen goes to the patient's right

hemisphere, which does not control language. When asked what they see,

patients cannot name the object but can pick it out by touch with the left

hand.

The left frontal lobe (colored regions at left) supports our ability to retrieve the meaning of words and objects. (Courtesy of Prof. Anthony Wagner.)

Highlights of this Course

This course features selected lecture notes associated with lecture content and readings. The assignments give students the opportunitiy to delve into the course's subject matter by writing research proposals and delivering class presentations.

Course Description

Surveys the literature on the cognitive and neural organization of human memory and learning. Includes consideration of working memory and executive control, episodic and semantic memory, and implicit forms of memory. Emphasizes integration of cognitive theory with recent insights from functional neuroimaging (e.g., fMRI and PET). Staff

Instructor: Prof. Anthony Wagner Course Meeting Times

The Forebrain.

The forebrain consists of the two cerebral hemispheres.

Each hemisphere receives sensory information from the opposite (contralateral) side of the body, and controls the muscles on the contralateral side of the body.

The outer cellular layer of the hemispheres is called 'cortex' and consists of gray matter, axons descend from the cortex to form 'white matter'.

Hubel & Wiesel (1979): the cortex contains around 50-100 billion neurons, unfolded it would occupy an area of 2000cm

Neurons in one hemisphere communicate with corresponding areas of the other hemisphere via two fibre pathways: the corpus callosum, and the anterior commissure.

Key Features of the Forebrain.

White matter

Grey matter

Corpus callosum

Lateral ventricle

Anterior commissure

Central sulcus

Longitudinal fissure

Examples of Laminar Differences.

Layer IV contains small cells that receive sensory information and this layer is prominent in cortical regions which process sensory information.

Layer IV is absent in brain regions that control movement.

It is thicker in the visual cortex of people with photographic memories, and in the auditory cortex of musicians (Scheibel, 1984).

Layer V contains large pyramidal cells which are responsible for motor control.

Such cells predominate in areas of motor cortex.

Mapping the Cortex

Maps have been developed of cortical subregions based upon differences in cell density, cell shape, size, and connectivity.

Divisions based upon structural criteria define functional zones such as specialised areas for touch, perception and even distinct cognitive processes.

Columnar Organisation.

Cells that perform similar functions are organised into collumns each around 3mm deep, arranged perpendicular to the laminae.

E.g. if a single cell within a column responds to touch on the palm of the left hand, then other cells within the same column will also respond to that stimulus.

Mountcastle (1979) referred to these columns as 'macrocolumns' and estimated that around a million of them existed in human cerebral cortex.

These can be further subdivided into 'minicolumns' and there are an estimated half a billion of them.

1. Frontal Lobes.

These extend from the central sulcus to cover the anterior portion of the brain.

They contain:

Primary motor cortex (area 4).

Premotor cortex (area 6).

Broca's area (area 44).

Prefrontal cortex.

Each receives input from the thalamic nuclei, limbic system, hypothalamus, and the other lobes, making it a 'control centre'.

Damage to the frontal part of the brain is thus likely to affect behaviour

Motor Cortex

Damage to the motor areas (4 and 6) produce a range of impairments to the motor system including:

Loss of fine motor control.

Reduction in strength.

Interruption of open-loop motor programmes (sequences of fast muscle actions (e.g typing, piano playing, speech).

This area also controls fine movements of the facial muscles, patients with frontal lobe damage show relatively little spontaneous facial expression (Kolb & Whishaw, 1990).

Broca's Area.

In 1861 Broca reported the case of a man who

had lost the power of speech (though he could

could still make speech noises and understand

speech).

At autopsy the damage was found to be localised

to a specific region on the left hemisphere of

frontal cortex.

This impairment is now referred to as Broca's

aphasia and is characterised by slow, deliberate

speech with a very simple grammatical structure.

Role of Prefrontal Cortex.

A key role of prefrontal cortex concerns working memory - the ability to retain pieces of information for short periods of time (Goldman-Rakic, 1984).

Brain imaging studies, case studies of brain-damaged humans, single-cell recordings confirm that this region is extremely active during delayed response tasks.

Prefrontal cortex is also involved in higher-order cognitive behaviours:

Planning.

Organisation.

Monitoring events, their outcomes, and the emotional value of such actions (Tucker et al., 1995).

Cognitive Impairments Following Frontal Lobe Damage.

Milner & Petrides (1984) reviewed the effects of frontal lobe damage in humans and concluded that the following behaviours were impaired:

Temporal sequencing: i.e the ability to say which of 2 pictures had been presented most recently.

Shifting of attention: there is an increased tendency to persevere with an action when it is obviously incorrect (perseveration).

Conditional associations: the ability to associate a correct response with a particular stimulus.

Working memory: the ability to maintain a response in memory and then act upon it appropriately.

Parietal Lobes

Damage to the Parietal Lobes.

Damage here produces deficits in tactile function, disorders of body image, right-left confusion, and disorders of spatial ability (Kolb & Whishaw, 1990).

A common feature is sensory neglect, the tendency to ignore one side of the body or features of the outside world.

target

Patients response

The Binding Problem.

We perceive an integrated world despite the fact that neural processing is conducted by distinct (but interconnected) modules.

How are separate functions integrated?

As yet this remains a mystery but Robertson et al., (1997) proposed that regions of parietal cortex may serve to combine different aspects of information to form a coherent whole.

This theory is based upon individuals with brain damage to parietal cortex who can no longer bind together different aspects of perception.

Frontal Lobe - Front part of the brain; involved in planning, organizing, problem solving, selective attention, personality and a variety of "higher cognitive functions" including behavior and emotions.

The anterior (front) portion of the frontal lobe is called the prefrontal cortex. It is very important for the "higher cognitive functions" and the determination of the personality.

The posterior (back) of the frontal lobe consists of the premotor and motor areas. Nerve cells that produce movement are located in the motor areas. The premotor areas serve to modify movements.

The frontal lobe is divided from the parietal lobe by the central culcus

Parietal Lobes

Damage to the Parietal Lobes.

Damage here produces deficits in tactile function, disorders of body image, right-left confusion, and disorders of spatial ability (Kolb & Whishaw, 1990).

A common feature is sensory neglect, the tendency to ignore one side of the body or features of the outside world.

target

Patients response

The Binding Problem.

We perceive an integrated world despite the fact that neural processing is conducted by distinct (but interconnected) modules.

How are separate functions integrated?

As yet this remains a mystery but Robertson et al., (1997) proposed that regions of parietal cortex may serve to combine different aspects of information to form a coherent whole.

This theory is based upon individuals with brain damage to parietal cortex who can no longer bind together different aspects of perception.


Prof. Ion V. Moldovanu

Catedra de Neurologie

Universitatea de Medicin i Farmacie N.Testemitanu

Neuropsihologia clinică

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