The Development of the Human Neocortex
The book, Human Neocortical Development, is a sequel to our 1991 book, Neocortical Development, in the rat (presented below). We used our extensive photographic library of human embryonic, fetal, and some neonate specimens along with the sparse classical literature on human neocortical development. Some important developmental events, like the partitioning of the stratified transitional field (STF, the old intermediate zone) into distinctive lamination patterns of interacting migrating neurons and incoming and outgoing axons, are presented in an expanded set of diagrams and illustrations. The STF was discovered in rats, and it is much more pronounced in humans. Please see the link below for a 2002 paper on the human STF that appeared in the Journal of Neurocytology. STF documentation photographs were illustrated in our 5-volume series, Atlas of Human Central Nervous System Development. This book treats that topic, and many other new observations in a concentrated look at only the human neocortex. The greatest part of the book is a series of annotated illustrations showing early to late developmental events, beginning with the appearance of the neocortical neuroepithelium and ending with an extensive documentation of myelination sequences and the appearance of cortical gyri. The book concludes with a discussion of hypotheses and interpretations of neocortical circuitry development and introduces a novel concept about an anchoring system that establishes the depths of early fissures and gyri in the initially smooth cortex. The illustrations on the right explain our hypothesis of an anchoring system (modified from Figure 80B, top and Figure 81, bottom) in the final part of the book.
The link below is the pdf file of the entire book containing over 200 pages; the file is nearly 25 MB because of the extensive photographs included. The Laboratory of Developmental Neurobiology is offering this as a free book to anyone who wishes to learn more about human neocortical development. Enjoy reading! Please use the contact page to let us know what you think of our interpretations.
The Development of the Rat Neocortex
The photo series here shows the different levels we used to determine the time of origin of neurons in different parts of the neocortex with 3H-thymidine autoradiography (Chapter 3, Figure 3-6; pdf file #5, bottom list). L1-L5 are the levels from most anterior (1) to most posterior (5).
The straight black bars separate different areas of the cortex: Ai-agranular insular, CG- cingulate, FR-frontal, GU-gustatory, OCL-lateral occipital, OCM-medial occipital, PAR-parietal, PR-perirhinal, RS-retrosplenial, TE-temporal. The dashed lines indicate dorsomedial (DM), dorsolateral (DL) and ventrolateral (VL) strips of cortex that are reproduced at high magnification in Chapter 3, Figure 3-7 (pdf file #5, bottom list).
We think that the concepts presented in this book are relevant today, and this developmental treatise remains the most comprehensive study of neocortical development in any mammal. The recent research on gene expression studies confirms some of our observations and speculations about the mechanisms at work during neocortical development.
Rat Neocortical Development Book Files By Part and Chapter
Part I: Overview of Major Events in Cortical Development
Ch 1: Early Cortical Development
Ch 2: Neocortical Morphogenesis and Histogenesis
Ch 3: Overview of Global Neurogenetic Gradients in the Neocortex and Limbic Cortex
Part II: Embryonic Development of the Neocortex
Ch 4: The Germinal Matrix of the Developing Rat Neocortex
Ch 6: Development of the Cortical Plate
Ch 7: Stratification in the Cortical Transitional Field
Ch 8: Quantitative Studies of the Nuclear Area and Orientation in the Developing Neocortex
Ch 9: Cell Migration in the Developing Neocortex
Ch 10: Experimental Studies of Neocortical Development Using x-Irradiation
Part III: Intrinsic Neurogenetic Gradients in Specific Neocortical Areas
Ch 11: Development of the Visual Areas
Ch 12: Development of the Auditory Areas
Ch 13: Development of the Somatosensory Areas
Ch 14: Development of the Motor Areas
Ch 15: Development of the Limbic Cortical Areas
Part IV: Theoretical Issues, Summary, and Conclusions
Ch 17: Summary and Conclusions
Appendix 1: Histological Procedures for Normative Embryonic Studies