Izabelo zobuchopho
Ama-hemispheres amakhulu ahlukaniswe zibe izingxenye ezinamagama abo anikezwa ngamathambo azihlanganisa: • I-lobes yangaphambili ikhona phambi kweRandand nangaphezulu kwe-furrow yaseSylvia.
• I-lobe ye-temporal ihlezi ngemuva kwesigaba esiphakathi nangaphezulu kwesigaba esilandelayo se-sulcus lateral; ibuyele emuva emfuleni we-parieto-occipital - igebe elihlukanisa lobe parietal kusuka occipital, edala ingxenye posterior ubuchopho.
• I-lobe yesikhashana yindawo esekelwe ngaphansi kwe-furrow sylvia kanye nomngcele osuka ngemuva nge-lobe occipital.
Njengoba ubuchopho bukhula ngamandla ngaphambi kokubeletha, i-cortex ye-cerebral iqala ukwandisa ubuso bayo, ihlanganise amaphuphu, okuholela ekubunjweni kokubonakala kobuchopho obufana ne-walnut. Lezi zibopho ziyaziwa njenge-convolutions, ama-grooves ehlukanisa izimpande zawo abizwa ngokuthi imisele. Imifudlana ethile kubo bonke abantu isendaweni efanayo, ngakho isetshenziswe njengemihlahlandlela yokuhlukanisa ubuchopho zibe izingxenye ezine.
Ukuthuthukiswa kwe-convolutions nemifula
Imifula kanye ne-convolutions iqala ukuvela ngenyanga yeshumi nantathu yokuthuthukiswa kwe-fetus. Kuze kube yileso sikhathi, ubuchopho buhlala bushelelezi, njengobuchopho bezinyoni noma ama-amphibians. Ukwakhiwa kwesakhiwo esihlotshisiwe kunika ukwanda endaweni ephezulu ye-cortex ye-cerebral ezimweni zomthamo olinganiselwe we-cranium. Izingxenye ezahlukene ze-cortex zenza imisebenzi ekhethekile, ekhethekile kakhulu. I-cortex ye-cerebral ingahlukaniswa ezindaweni ezilandelayo:
• Izindawo zokuhamba ngemoto - qalisa futhi ulawule ukunyakaza komzimba. Indawo eyinhloko yezimoto ilawula ukunyakaza okungaqondakali kolunye uhlangothi lomzimba. Ngokuqondile phambi kwe-motor cortex yiyona ebizwa ngokuthi i-premotor cortex, futhi isifunda sesithathu - indawo eyengeziwe yezimoto - ilele endaweni yangaphakathi ye-lobe yangaphambili.
• Izindawo ezibonakalayo ze-cortex ye-cerebral zibona futhi zikhiqize ulwazi oluvela kuma-receiver sensitive kulo lonke umzimba. Indawo eyinhloko ye-somatosensory ithola ulwazi oluvela ohlangothini oluhlukile lomzimba ngesimo sezimvo ezivela emithonjeni ebucayi bokuthintana, ubuhlungu, izinga lokushisa kanye nesimo samalungu namasipha (ama-receptors enempahla).
Ubuso bomzimba womuntu "buba khona" emibonweni yayo nasemijondolo ye-cortex ye-cerebral, ehlelwe ngendlela ethile. I-neurosurgeon yaseCanada iWilder Penfield, eyasebenza ngawo-1950, yakha imephu eyingqayizivele yezindawo ezizwelayo ze-cortex ye-cerebral, ebona ulwazi oluvela ezingxenyeni ezihlukahlukene zomzimba. Njengengxenye yocwaningo lwakhe, wenza ucwaningo lapho aphakamisa ukuthi umuntu ngaphansi kwe-anesthesia yendawo uchaza imizwa yakhe ngesikhathi avuselela izindawo ezithile zobuso bobuchopho. U-Penfield wathola ukuthi ukugqugquzelwa kwe-gyrus ye-postcentral kubangele ukuzwa okujulile ezindaweni ezithile ezingxenyeni ezingafani zomzimba. Olunye ucwaningo luye lwabonisa ukuthi ivolumu ye-motor cortex enomthwalo wezindawo ezihlukene zomzimba womuntu ixhomeke kakhulu ezingeni lokubunzima nokuchithwa kokunyakaza okwenziwe kunokuba namandla namandla we-muscle mass. I-cortex ye-cerebral iqukethe izendlalelo ezimbili eziyinhloko: udaba olumpunga luyingqimba elincane lamangqamuzana angamazinyo nama-glial angaba ngu-2 mm obukhulu nomuthi omhlophe owenziwe ngamagciwane omzimba (ama-axons) namaseli we-glial.
Ubuso be-hemispheres amakhulu buhlanganiswe ngendwangu yendaba eluhlaza, ubukhulu bayo buhluka kusuka ku-2 kuya ku-4 mm ezingxenyeni ezihlukene zobuchopho. Indaba ebomvu ikhiwa yizidumbu zamangqamuzana omzimba (neurons) nama cell glial enza umsebenzi osekelayo. Eziningi ze-cortex ye-cerebral, izingqimba eziyisithupha ezihlukene zamaseli zingatholakala ngaphansi kwe-microscope.
I-Neurons ye-cortex ye-cerebral
Izidumbu (eziqukethe i-nucleus cell) ye-neurons ye-cortex ye-cerebral zihluke kakhulu emafomu abo, noma kunjalo, yizona ezimbili eziyinhloko kuphela ezivelele.
- Amaseli e-pyramidal athola igama lawo ekujuleni komzimba we-neuron, ofana nephiramidi; ama-axon (ama-fibrous fibers) avela ku-cortex ye-cerebral futhi athathe ulwazi kwezinye izingxenye zobuchopho.
- Amaseli angewona ama-pyramidal (bonke abanye) aklanyelwe ukubona nokucubungula ulwazi kusuka eminye imithombo.
Ubukhulu bezingqimba eziyisithupha zamaseli ezakha i-cortex ye-cerebral zihluka kakhulu kuye ngokuthi indawo yobuchopho. Isazi sezinzwa saseJalimane uCorininian Broadman (1868-191) saphenya ngalezi zohlukaniso ngokugcoba amangqamuzana omzimba futhi zibuke ngaphansi kwe-microscope. Umphumela wocwaningo lukaSuddmann lwesayensi kwaba ukuhlukaniswa kwe-cortex ye-cerebral ezindaweni ezingama-50 ezihlukene ngesisekelo sezinqubo ezithile ezithinta umzimba. Ucwaningo olulandelayo luye lwabonisa ukuthi "amasimu e-Brodmann" ngaleyo ndlela ayodwa ayidlala indima ethile yomzimba futhi abe nezindlela ezihlukile zokuxhumana.