caa a22 4500 397582188 CHVBK 20180308164910.0 cr unu---uuuuu 161202e199605 xx s 000 0 eng 10.1093/cercor/6.3.490 doi (NATIONALLICENCE)oxford-10.1093/cercor/6.3.490 Neuronal Clones in the Cerebral Cortex Show Morphological and Neurotransmitter Heterogeneity during Development [Elektronische Daten] [Alexandros A. Lavdas, Marina C. Mione, John G. Parnavelas] The mammalian cerebral cortex, although a structure of great complexity, is characterized by a high degree of organization where the proportions, spatial relationships, and properties of the various cell types are rigidly controlled. The mechanisms responsible for the creation of such a rigid distribution of cell types are not known. Lineage studies in adult rats have suggested that each of the cortical progenitor cells lining the telencephalic ventricles during embryonic development gives rise to progeny of the same phenotype (homogeneous clones). However, the possibility that homogeneous clones are the result of complex processes affecting both the final number and the phenotype of clonally related cells during development has not been investigated. In the present study, we followed the development of cortical cell lineages labeled with retroviral injections at embryonic day (E) 16 in rats of 7, 14, or 21 d of age using electron microscopy and immunocytochemistry for the neurotransmitters glutamate and GABA. We found that a significant number of cortical clones at postnatal day (P) 7 and P14, and fewer at P21, showed mixed pyramidal/nonpyramidal cell composition. We sometimes observed that "mixed” neuronal clones contained cells immunoreactive for both glutamate and GABA. In the general population of cortical cells, "bireactive” neurons represented 3.7% of all neurons at P7, 1.8% at P14, and 0.6% in adult rats. Although the change in the composition of neuronal clones between the third week of postnatal life and adulthood may be due to changes in the phenotype of some developing neurons, we would like to suggest that it is probably due to selective neuronal cell death. © 1996 Oxford University Press Article nationallicence Lavdas Alexandros A. Department of Anatomy and Developmental Biology, University College London, London WC1E 6BT, United Kingdom aut Mione Marina C. Department of Anatomy and Developmental Biology, University College London, London WC1E 6BT, United Kingdom aut Parnavelas John G. Department of Anatomy and Developmental Biology, University College London, London WC1E 6BT, United Kingdom aut Cerebral Cortex Oxford University Press 6/3(1996-05), 490-497 1047-3211 6:3<490 1996 6 cercor https://doi.org/10.1093/cercor/6.3.490 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1093/cercor/6.3.490 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Lavdas Alexandros A. Department of Anatomy and Developmental Biology, University College London, London WC1E 6BT, United Kingdom aut NATIONALLICENCE 700 1- Mione Marina C. Department of Anatomy and Developmental Biology, University College London, London WC1E 6BT, United Kingdom aut NATIONALLICENCE 700 1- Parnavelas John G. Department of Anatomy and Developmental Biology, University College London, London WC1E 6BT, United Kingdom aut NATIONALLICENCE 773 0- Cerebral Cortex Oxford University Press 6/3(1996-05), 490-497 1047-3211 6:3<490 1996 6 cercor Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford