Ulwahlulo lwengqondo
Ama-hemispheres amakhulu anqatshelwe kwiindawo apho amagama abo anikezwa ngamathambo awagubungelayo: • I-lobes yangaphambili ikhona phambi kweRoland kunye ne-furrow yeSyloveni.
• I-lobe yexesha lexesha ihleli ngasemva kunye nangaphezulu kwesahlulo esingasemva sulus; ibuyele kwi-furari-occipital furrow - isithuba esahlukanisa i-loari ye-parietal kwi-occipital, eyenza inxalenye engaphantsi kwengqondo.
• I-lobe yesikhashana yindawo ephantsi komsele we-sylvia kunye nomda osuka ngasemva nge-lobe yama-occipital.
Njengoko ubuchopho bukhula ngamandla ngaphambi kokuzalwa, i-cortex ye-cerebral iqala ukwandisa umgangatho wayo, ukudala izipho, ezikhokelela ekwakheni ukubonakala kwimizimba yengqondo efana ne-walnut. Ezi zigulo zibizwa ngokuba yi-convolutions, ama-grooves ahlula ama-grooves awo abizwa ngokuba yimifula. Ezinye iindawo zokuhlala kuzo zonke indawo zihlala kwindawo enye, ngoko zisetyenziswe njengezikhokelo zokuhlula ingqondo kwiindawo ezine.
Uphuhliso lwee-convolutions kunye nemigxobhozo
Iiforrow kunye ne-convolutions ziqala ukuvela kwinyanga yesithathu ye-intuthuko yomntwana. Kuze kube ngoko, ubuchopho buhlala busheleleka, njengengqondo yeentaka okanye i-amphibians. Ukwakhiwa kwesakhiwo esiqhotyoshelweyo kunika ukwanda kwendawo yommandla we-cortex ye-cerebral kwiimeko ze-kratri encinane. Iindawo ezahlukeneyo ze-cortex zenza ethile, imisebenzi ekhethekileyo. I-cortex ye-cerebral ingahlukaniswa kwiindawo ezilandelayo:
• Iindawo zokuqhuba iimoto - ziqalise kwaye zilawula ukunyakaza komzimba. Ummandla oyintloko wendlela yokulawula ulawulo lokuhamba ngokungenakuphikisana kolunye uhlangothi lomzimba. Ngokukhawuleza phambi kwe-cortex yemoto yinto ebizwa ngokuba yi-premotor cortex, kunye nommandla wesithathu-indawo eyongezelelweyo yemoto - ihlala kwindawo yangaphakathi ye-lobe yangaphambili.
Iindawo eziqhelekileyo ze-cortex ye-cerebral ziyaqonda kwaye zivelise ulwazi oluvela kwi-receptors ezibuhlungu kuwo wonke umzimba. Ummandla we-primary somatosensory ufumana ulwazi oluvela kwicala eliphambene nomzimba ngesimo semiphumo evela kwizixhobo eziphathekayo zokuthintela intlungu, intlungu, izinga lokushisa kunye nesimo samalungu kunye nezihlunu (i-receiver receptors).
Umgangatho womzimba womntu une "impawu" zayo kwiimvakalelo kunye nemithi ye-cortex ye-cerebral, ehlelwe ngendlela ethile. I-neurosurgeon yaseCanada iWilder Penfield, eyasebenza kwiminyaka yama-1950, yakha imephu ekhethekileyo yemimandla yechungechunge ye-cortex ye-cerebral, ebona ulwazi oluvela kwiindawo ezahlukahlukeneyo zomzimba. Njengengxenye yophando lwakhe, wenza iimvavanyo apho wayecetyiswa ukuba umntu ongaphantsi kwe-anesthesia yendawo achaza iimvakalelo zakhe ngexesha apho wavuselela iindawo ezithile zommandla wengqondo. U-Penfield wafumanisa ukuba ukuvuselela i-gyrus ye-postcentral kubangele ukuvakalelwa kwintsimi ethile kwinqanaba eliphambene lomzimba. Ezinye izifundo zibonise ukuba umthamo we-motor cortex ojongene nemimandla eyahlukeneyo yomzimba womntu kuxhomekeke ngakumbi kwizinga leenkathazo kunye nokuchaneka kweentshukumo ezenziwayo kunokuba namandla kunye nomthamo wobunzima bomzimba. I-cortex ye-cerebral iqulethe ezimbini ezibalulekileyo: i-gray matter iyinxalenye encomekileyo yamaseli kunye ne-glial cells malunga no-2 mm ubukhulu kunye nomzimba omhlophe owenziwe yimibindi ye-nerve (i-axons) kunye neeseli ze-glial.
Ubuso be-hemispheres amakhulu buhlanganiswe ngongqimba lwendoda ebomvu, ubunzima balo buhluka ukusuka kwi-2 ukuya kwi-4 mm kwiindawo ezahlukeneyo zobuchopho. Umba ompunga ukhiwa ngamalungu omzimba weentsimbi (neurons) kunye neeseli ze-glial ezenza umsebenzi oxhasayo. Kwinkoliso ye-cerebral ye-cerebral, amanqaku athile ahlukeneyo amaseli angabonwa phantsi kwe-microscope.
I-Neurons ye-cortex ye-cerebral
Imizimba (equkethe iisucleus cell) ye-neurons ye-cortex ye-cerebral ihluke kakhulu kwifomu yayo, kodwa ke, kuphela ezimbini ezibalulekileyo ezihlukeneyo.
- Amaseli ePyramidal athatha igama lawo kumfanekiso womzimba we-neuron, ofana nepiramidi; ii-axon (i-nerve fibers) zivela kwi-cortex ye-cerebral kwaye zithwala ulwazi kwezinye iindawo zobuchopho.
- Iiseli ezingekho-pyramidal (zonke ezinye) zenzelwe ukuqonda nokucwangcisa ulwazi oluvela kwezinye iindawo.
Ubukhulu beetandathu ezintandathu zeeseli ezenza i-cortex ye-cerebral ziyahluka kakhulu kuxhomekeke kwingingqi yengqondo. Ingcali yegazi yaseJamani uKorbinian Broadman (1868-191) yaphanda le ngxabano ngokutshatyalalisa iiseli zesisongela kwaye ibukela phantsi kwe-microscope. Isiphumo sophando lwezesayensi lwe-Brodmann sasikwahlula i-cortex ye-cerebral kwiindawo ezingama-50 ezahlukileyo ngokwemigaqo ethile ye-anatomical criteria. Uphando olulandelayo luye lwabonisa ukuba "iindawo ze-Brodmann" zodwa zidlala indima ethile yomzimba kwaye zineendlela ezikhethekileyo zokusebenzisana.