Annual Meeting of the Society for Neuroscience edition:34 location:San Diego, CA, U.S.A. date:October 23-27, 2004
It is now established that neurofilament protein has become a powerful tool for the parcellation of brain regions in different mammalian species. Nevertheless, there are no reports on mouse cortical organization based on a characteristic expression pattern of neurofilament protein. We therefore examined neurofilament protein staining profiles in mouse visual system as revealed with the SMI-32 monoclonal antibody. Neurofilament protein-positive neurons were prominent in six visual areas, but a remarkably reduced staining profile was present in the secondary visual areas. Topographic boundaries between adjacent areas could be delineated by a characteristic pattern of neurofilament protein such as differences in laminar distribution patterns, morphological and cellular characteristics and staining profiles. SMI-32 immunoreactivity was present in the dendrites and cell bodies of a subset of pyramidal neurons in three cortical layers III, V and VI. However, a minority of cortical layer II cells was also positive for neurofilament protein. We also found immunoreactivity in several subcortical structures. Although the dorsal and ventral lateral geniculate nucleus showed a strong immunolabeling, no cellular or fibrillary pattern was present in the intergeniculate leaflet. In addition, the laminar organization within the superior colliculus was clearly discernible based on differences in size and shape of positive cells and the dendritic arborization profile for neurofilament protein. The present study clearly shows that neurochemical subdivision of mouse visual system exists and is highly specific demonstrating organizational and functional characteristics at the cellular and regional level.