The brain of mammals is not believed to add any more nerve cells (neurons) after birth, although the functional connections of the nervous system may continue to increase, and be modified by experience. There are whole populations of identifiably different classes of cells in the nervous system, and much of neuroscience is concerned with determining the structure and function of such classifiable cell groups. This small pilot project will use a transgenic biotechnology as a novel approach to see whether a one class of photoreceptor cells in the eye can be selectively destroyed. Molecular biological techniques will be used to produce a strain of mice containing a toxic gene linked to a normal gene coding for a pigment molecule important in photoreception; when a photoreceptor cell starts to make its internal pigment, the toxic gene also will be expressed to kill the cell. Anatomical and neurophysiological data will be used to test the efficacy of the removal. The capability of selective deletion of specific classes of cells in the nervous system will provide a new tool for correlating function with structure, and will have a big impact on many areas of neuroscience and developmental biology.
