Mouse Lemur Brain Putative Cytoarchitectonic MapRationale and methods |
||
| Our group investigate age related cerebral atrophy in mouse lemurs by MRI [Neurobiology of Aging (2000), 21, 81]. We are particularly interested in evaluating the functional areas that become atrophied in aged animals. In humans and animals, designation of cortical functional regions is mainly based on Brodmann's "maps" of the cerebral cortex. These maps display functional "areas" in human, monkeys and other mammals' brain. The location of Brodmann's area in the brain of mouse lemurs has been described in 1931 by W E Le Gros Clark [The brain of Microcebus murinus. Proceedings of the Zoological Society London, 463-485]. Unfortunately this paper only displays 9 sections of the brain and maps of lateral and medial views of the brain. These information were insufficient to estimate the function of the brain areas that are atrophied in mouse lemurs. Until now, the only extensive atlas of mouse lemurs' brains is the one by Bons et al. published in a special issue of 'Brain Research Bulletin' and in a book. It provides an excellent location of many cerebral structures in the brain of mouse lemurs, but, cortical areas were not defined in this atlas. In this work, images from the Bons' Atlas were scanned and used as templates to paste Brodmann's areas described in the Le Gros Clark paper: We virtually sliced the lateral and medial views described in the latter paper with a slicing plane that was similar to that used in the Bons' atlas. Then we pasted the Brodmann's areas as described by Le Gros Clark onto the templates. The consistency of the result was evaluated by comparing the location of the newly drawn cytoarchitectonic areas and the one displayed in the 9 sections provided by Le Gros Clark (the slicing planes were different in the two atlases). We also outlined and annotated the brain areas that are filled by cerebro-spinal fluids such ventricles or sulci. The atlas is provided as an interactive tool created by using the MetaMAP® object indexing technology (Eolas Technologies inc. (See Dhenain et al. Developmental Biology. 2001; 232: 458-70, for further description of the method). Selecting an area on the image via a mouse click, sends information regarding the selected area. This atlas provide a rough location of cytoarchitectonic areas in the brain of mouse lemurs. Because this study is not a true cytoarchitectonic study, but only a bibliographic evaluation, it should be regarded only as an indication of Brodmann's areas location. It was created as a working tool to help us in the evaluation of the relationship between cerebral atrophy and functional areas. It was put on the web hoping that it might be useful to anybody interested in the brain of mouse lemurs. |
||