Naslov
Neuronal phenotypes in transient cellular zones of the developing human neocortex.

Autori
Kostović, Ivica ; Judaš, Miloš ; Petanjek, Zdravko

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Cajal Club Internation Symposium: Camilo Golgi and Modern Neuroscience. Pavia, Italy, 2009, Abstract Book / - Pavia, 2009

Skup
Cajal Club Internation Symposium: Camilo Golgi and Modern Neuroscience.

Mjesto i datum
Pavia, Italija, 29.09.2009. - 01.10.2009

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
neocortex; subplate; fetus; human

Sažetak
Postmigratory neurons of the fetal cerebral cortex reside and differentiate within transient cellular compartments which do not have counterparts in the adult cortex: the cortical plate (CP), the second CP and the subplate (SP). Some of these compartments are more prominent in human than in rodent cortex, indicating their special role in complex, protracted development of cortical circuitry in primates. In this paper we correlate changing neuronal phenotypes (Golgi method) with aggregation and disaggregation of transient cellular compartments (Nissl staining) and distribution of synapses (EM) before, during and after the formation of the SP (fetuses aged 10 to 18 postconceptional-weeks - PCW). In the early fetal cortex (10 PCW) neurons of the CP display bipolar orientation of dendrites with arborizations in the pre-SP (below the CP) and marginal zone (MZ) (above the CP). Thin pre-SP contains scattered polymorphic neurons with well developed dendrites. The distribution of synapses is bilaminar: below and above the CP. Around 13 PCW, during the formation of the SP, neurons in the second (“loose”) part of CP change their radial orientation. Variety of neuronal shapes and orientations appear in the transitional zone towards the developing deep SP. Synapses are present throughout the second CP and developing SP. After 15 PCW the CP undergoes secondary consolidation and newly arrived postmigratory neurons show radial orientation and immature pyramidal shapes (radial columns). This newly consolidated and dense CP contains no synapses. In contrast, synapses are present throughout entire thickness of the SP. SP phenotypes are predominantly non-pyramidal, randomly oriented. In conclusion, the phenotype of postmigratory neurons is changing depending on position in transient cellular zones and availability of synaptic inputs. Experimental studies have shown that synaptic input to neurons with transient phenotypes is a mixture of glutamatergic, gabaergic, cholinergic and monoaminergic. These studies have also shown that neurons with transient phenotypes are included in endogeneous, oscillatory activity. The richness of transient neuronal phenotypes and the phenomenon of second CP as well as the prominence of the SP strongly suggest that endogenous circuitry is best developed in the human cortex and exists over prolonged time of intrauterine development. Our results strongly support the concept that achievement of adult-like neuronal phenotypes (pyramidal and nonpyramidal) is not accomplished solely by progressive differentiation, but includes a series of reorganizational events in dendritic profiles.

Izvorni jezik
Engleski

Znanstvena područja
Temeljne medicinske znanosti

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