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Uvod: Razvoj strijatuma započinje oko sedmog postkoncepcijskog tjedna kad započinje migracija prvih stanica iz ganglijskog brežuljka, a doseže svoj vrhunac između 20.i 24.tjedna. Nakon tog perioda započinje perinatalna i postnatalna reorganizacija građe. Postizanje završnog stadija organizacije nije točno vremenski određeno u literaturi. Cilj ove studije odrediti je krivulju rasta strijatuma i povezati je s promjenama u intrinzičnoj organizaciji. Nadalje, uspoređivane su promjene u volumenu strijatuma s rastom volumena hemisfera u fetalnom i ranom postnatalnom periodu. Materijali i metode: Studija uključuje 40 ispitanika: 5 novorođenčadi rođenih u terminu, 15 normotipičnih s urednim nalazom MR-a i urednim kliničkim nalazima, 15 postmortalno snimljenih fetalnih mozgova (iz Zagrebačke Neuroembriološke Zbirke) starosti 13 do 40 postkoncepcijskih tjedana, te 5 djece starosti 1 mjesec do 1 godine. Svim je skupinama snimljen MR mozga, dalje obrađen semi-automatskim i manualnim metodama segmentacije. Rezultati: Linearan rast strijatalnih komponenata prati porast volumena hemisfera i mozga u cijelosti od 13. postkoncepcijskog tjedna do jedne godine starosti. Najbrži porast volumena zabilježen je između 20. i 28. postkoncepcijskog tjedna, s vrhuncem porasta u 24.tjednu. Zaključci: Naše istraživanje pokazalo je linearan rast promatranih struktura (volumen nucleus caudatus, putamen i hemisfera) u fetalnom, neonatalnom i perinatalnom razdoblju s vršnom vrijednosti u 24.tjednu. Dobiveni rezultati odgovaraju tranziciji prema strukturi odraslog mozga koja traje do kraja postnatalnog perioda (1.godina života). Zanimljivo je da je vršna vrijednost volumena postignuta tijekom maksimalne izraženosti modularne organizacije što odražava intenzivan razvoj kortikostrijatalnih projekcija.

The corpus callosum connects two cerebral hemispheres as the most voluminous fiber system in the human brain. The developing callosal fibers originate from immature pyramidal neurons, grow through complex pathways and cross the midline using different substrates in transient fetal structures. We analyzed cellular structures in the human corpus callosum on postmortem brains from the age of 18 weeks post conception to adult, using glial fibrillary acidic protein, neuron- specific nuclear protein, and chondroitin sulphate immunocytochemistry. We found the presence of transient cellular structures, callosal septa, which divide major fiber bundles and ventrally merge with subcallosal zone forming grooves for callosal axons. The callosal septa are composed of glial fibrillary acidic protein reactive meshwork, neurones and the chondroitin sulphate immunoreactive extracellular matrix. The developmental window of prominence of the callosal septa is between 18-34 weeks post conception which corresponds to the period of most intensive growth of callosal axons in human. During the early postnatal period the callosal septa become thinner and shorter, lose their neuronal and chondroitin sulphate content. In conclusion, transient expression of neuronal, glial and extracellular, growing substrate in the callosal septa, as septa itself, indicates their role in guidance during intensive growth of callosal fibers in the human brain. These findings shed some light on the complex morphogenetic events during the growth of the corpus callosum and represent normative parameters necessary for studies of structural plasticity after perinatal lesions.

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In this study we have analysed the development of associative layer IIIc pyramidal neurons of the prefrontal cortex in children with DS during the late fetal and early postnatal period. Basal dendritic tree of rapid Golgi impregnated pyramidal neurons was quantitatively analysed (dendritic length ; number and morphology of dendritic spines) in the postmortal brains from 3 subjects with DS (fetus 36 weeks of gestation, infants aged 2.5 and 4.5 months) and in 5 age matched controls. During the perinatal period there is the most intensive dendritic growth and spinogenesis. No differ- Abstracts 417 ences were present between DS infants and control subjects concerning the pattern of the dendritic elongation and segment outgrowth. Increase in spine number followed in DS the normal curve up to third postnatal month. At 4 months decreased spine density was observed only on the most distal terminal branches. Some morphological alterations of the dendritic spines are present in DS subjects from the beginning of their occurrence. It was proposed that the basis of cognitive dysfunction in DS lies in the disordered development of their associative cortex. These data suggest that children with DS begin their life with morphologically normal layer IIIc prefrontal pyramids, which are the key cellular elements of the corticocortical connectivity. Since the first regressive changes are not present before the fourth postnatal month, it seems reasonable to conclude that the application of some therapeutic procedures in the early period of life could mitigate a cognitive decline present later in these patients.

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Istraživanje perinatalnih uzoraka minimalnih oštećenja mozga: vrijednost i značenje neuronatomskih parametara i kompjuterizirane tomografije (CT) u proučavanju oštećenja kortikostrijalnog sustava

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Analysis of serial sections revealed that six of 18 fetuses over 18 weeks had small, partially organized haemorrhage at the interface between ganglionic eminence and developing caudate nucleus. It was postulated that prenatal intrauterine (in fetuses) or early postnatal (low weight prematures) hemorrhage may damage both the production of striatum neurons and the development of their (cortical) neuronal connections.

Pineal cysts are benign glial uniloculated or multiloculated fluid-filled sacs located in the pineal gland region. Small pineal cysts are often found incidentally in healthy adults in 1.5-10.8%. Large cysts may cause neurological problems due to pressure exertion on adjacent structures