The Journal of Neuroscience, March 16, 2005, 25(11):2781-2792; doi:10.1523/JNEUROSCI.4770-04.2005
Previous Article | Next Article 
Development/Plasticity/Repair
Tangential Networks of Precocious Neurons and Early Axonal Outgrowth in the Embryonic Human Forebrain
Irina Bystron,1,3
Zoltán Molnár,2
Vladimir Otellin,3 and
Colin Blakemore1
1University Laboratory of Physiology, University of Oxford, Oxford OX1 3PT, United Kingdom, 2Department of Human Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, United Kingdom, and 3Department of Morphology, Institute of Experimental Medicine, St. Petersburg 197376, Russia
We used a combination of immunohistochemistry and carbocyanine dye tracing to study neurons and their processes in the human embryonic forebrain, 4-7 weeks after conception, before the onset of synaptogenesis. We discovered a widespread network of precocious MAP2 (microtubule-associated protein 2)-immunoreactive cells, with long, nonaxonal processes, before the appearance of the cortical plate and the establishment of thalamocortical connectivity. Dye tracing revealed that the processes of these precocious cells form tangential links between intermediate zones of the thalamus, ganglionic eminence, hypothalamus, and cortical preplate. The spatiotemporal distribution and morphology of the precocious neurons in the cortical preplate suggest that they are generated outside the cerebral wall rather than in the local ventricular zone. The first thalamocortical axons and axons of preplate cells extend across diencephalo-telencephalic and striatocortical boundaries before the arrival of the first cortical plate neurons. Precocious cells may provide initial communication between subdivisions of the embryonic brain as well as guidance cues for navigation of growing axons and/or transverse neuronal migration.
Key words: human forebrain development; pioneer neurons; thalamocortical and corticofugal projections; preplate; MAP2; GAP43
Received Nov 22, 2004;
revised January 24, 2005;
accepted January 24, 2005.
This article has been cited by other articles:

|
 |

|
 |
 
N. Bayatti, J. A. Moss, L. Sun, P. Ambrose, J. F. H. Ward, S. Lindsay, and G. J. Clowry
A Molecular Neuroanatomical Study of the Developing Human Neocortex from 8 to 17 Postconceptional Weeks Revealing the Early Differentiation of the Subplate and Subventricular Zone
Cereb Cortex,
July 1, 2008;
18(7):
1536 - 1548.
[Abstract]
[Full Text]
[PDF]
|
 |
|