Файл: The Embryonic Human Brain An Atlas of Developmental Stages. Third Edition. 2006. By Ronan O\'Rahilly-1.pdf

RONAN O’RAHILLY,

¨

FABIOLA MULLER,

M.D., D.Sc., Dr.h.c.

Dr.habil.rer.nat.

The main objectives of this monograph are to provide and to interpret drawings, photographs, and photomi-

crographs of the human embryonic brain. The drawings include at least a lateral view and a median reconstruction of the brain at each stage, as well as a clear indication of the plane of section of further illustrations, either drawings or photomicrographs. Summarizing statements of the morphological status of the brain at each stage are supplied, and brief statements concerning relevant anomalous conditions are included.

The embryonic period proper (the first eight postfertilizational weeks) is particularly important because (1) the embryonic brain is extremely difficult to comprehend and to visualize, (2) serial sections of first-class quality that show the human embryonic brain are rarely accessible, and (3) most major congenital anomalies appear during that time. A briefer account of the fetal period has been included and emphasizes the continuity of development.

Despite a general, superficial similarity in the development of the brains of various vertebrates, significant, subtle differences exist so that, undoubtedly important as are the findings in other species, contributions specifically to the prenatal human brain are as essential as they are fascinating.

The external and internal structure of the developing brain, the primary concern of this book, is an essential prolegomenon for subsequent investigations ranging from immunocytochemistry to imaging in vivo. Structural representation, however, needs to be completed by interpretation. In the present context two necessary components of precise interpretation are (1) morphological staging (as distinct from mere seriation, such as length or supposed age), without which individual events cannot be arranged in correct sequence, and (2) accurate three-dimensional reconstructions, without which erroneous assumptions of interpretation can be (and frequently are) made. These desiderata, which have been used by the authors in their research over many years, are a unifying feature of this treatise: (1) the Carnegie system of staging originated by Streeter and named and developed by the authors is fundamental to the presentation, and (2) most of the drawings here are based on extremely precise graphic reconstructions prepared by the authors. No similar work is available.

The authors’ scheme of the neuromeres, which differs from others in being based on the human, is detailed here. Other topics emphasized include segmentation, not only of the neural axis both rostrally and caudally, but also that of occipitocervical differentiation. Stem and crest cells in the olfactory region are elaborated, and the cerebellum, the amygdaloid complex, the hippocampal region, and the corpus striatum are given special attention.

This edition has been enhanced by the use of color, as well as by the inclusion of more that 100 new illustrations and 26 new tables. Moreover, some representative examples of ultrasonic images have been interspersed. The definitions formerly given in Chapter 6 have been expanded considerably and collected as an important Glossary near the end of the book.

The Bibliography has been enlarged and brought up to date. It comprises more than 350 references to the chief studies of the prenatal human brain. The profuse literature relating to other species, however, is beyond the scope of this book.

A set of standardized abbreviations, mostly selfevident, is used throughout for the illustrations, and a list of them is placed immediately inside the front cover.

The number assigned to chapters 8–23 and the first number given to each illustration indicate the developmental stage.

The authors wish to acknowledge the valuable support for their research provided by the U.S. National Institutes of Health over many years. Except where otherwise indicated, the photomicrographs as well as many of the photographs are from the Carnegie Collection. The scanning images are included through the kindness of Dr. med. Harm-Gerd Blaas and other colleagues who are credited in the appropriate places. It is a pleasure to thank all at WileyLiss for their encouragement and assistance.

RONAN O’RAHILLY

FABIOLA MULLER¨

Villars-sur Glane,ˆ Switzerland

July 2006