The image shown here is a sagittal slice of an E17 rat embryo that was killed 24 hrs after exposure to 3H-thymidine on E16. The black specs scattered throughout the embryo locate regions where mitotic cells have absorbed the label. The enlarged circular image on the left is of the posterior cerebral cortex overlying the habenula, on the right is the cerebellum.
BrainDevelopmentMaps.org provides archived histological materials of the developing rat brain used by Joseph Altman and Shirley A. Bayer in their research. The Laboratory of Developmental Neurobiology, continuously operating since the early 1960s with funding early on from the Atomic Energy Commission, The National Science Foundation, and the National Institutes of Health, accumulated a large “library” of normal and experimental histological material of the developing rat nervous system, both central and peripheral. This histological library contains one of the most complete sets of embryonic and early postnatal developmental materials that exists in the world. Our laboratory has used much of the material, but there is so much that can still be learned from an open viewing of the best specimens. Publications based on the analysis of these materials are available to the public in another website: neurondevelopment.org. The purpose of this website is to make the images available to students and researchers in developmental neurobiology and related fields. The use of these images is free, but if anyone reproduces them in a publication, credit should be given to this website. Each of the images presented has been generated by a high-resolution scanning microscope (Aperio scanscope) using either a 20X or a 40X objective. The individual fields of view have been knitted together to produce high resolution images that can be examined in two different ways: 1. Using Zoomify© to view the images directly from your browser window; and 2. Download a high resolution jpg file (some are up to 1gb!) that you can view using various other programs.
We are presenting two large sets of embryonic and postnatal rat nervous system specimens:
- 3H-thymidine autoradiograms— All of these specimens were either exposed to 3H-thymidine during embryonic life or directly injected with 3H-thymidine after birth (on specific days as indicated). The specimens were embedded in paraffin, processed for labeled thymidine (autoradiography), and post-stained with hematoxylin. We are most grateful for the excellent histological assistance of Sharon Evander. Sharon worked in our laboratory for over a decade, and with her help we perfected the complex technique of 3H-thymidine autoradiography. The AUTORADIOGRAPHIC BRAIN MAP SETS page contains information about the technique itself and how we used it to analyze brain development. All of these specimens were scanned at 20X with a Scanscope at the University of Florida molecular pathology core laboratory. We are grateful for the excellent work of Mary Reed and Caroline King. Some of the images were scanned by John Shelley and his team at the Sanford-Burnham Research Institute in Orlando, Florida.
- Plastic-embedded (methyl methacrylate) normal rat embryos to show stages in the development of cellular and fibrous components of the nervous system in three planes: sagittal, coronal (frontal), and horizontal. The METHACRYLATE BRAIN MAP SETS page contains an explanation of our methods. We were very lucky to have two gifted histologists, Libby Craft and Sarah Frazier, who worked at least 5 years on this project. Several other histologists worked on perfecting methacrylate techniques before Libby and Sarah. All specimens are normal embryos removed from pregnant rats on specific days of development. Methacrylate embedding preserves fine histological detail–nearly comparable to low magnification electron microscopy. There are 16 age groups: embryonic day (E) 10, E10.5, E11, E11.5, E12, E12.5, E13, E14, E15, E16, E17, E18, E19, E20, E21, and E22. The E10 and E10.5 groups were scanned at 40X by Mary Reed at the University of Florida. The rest of the age groups were scanned at 40X (and some older specimens at 20X) with a Scanscope at the Sanford-Burnham Research Institute in Orlando, Florida. We are grateful for the excellent work of John Shelley and his team of intern histologists–among them Yoanna Bello Arredondo and Rebecca Adams.
- Because all of these image sets take up many separate pages, we include a NAVIGATION PAGE of links to all other pages that open up in separate windows.