A major function of the brain is to initiate and direct an individual's behaviors. While behaviors are controlled by dispersed groups of highly intertwined neurons, the particular neurons responsible for particular behaviors have not been identified. This problem remains unsolved simply because there are so many neurons and their possible interconnections are so complex that the task seems Herculean. Dr. Coquelin's aim is to unravel this tangle by capitalizing on some recent advances in the fields of behavioral genetics and developmental biology. He has selected two different strains of inbred mice that differ in their expression of some specific hormonally induced behaviors. Dr. Coquelin will combine very young embryos from these two different inbred strains. The offspring, referred to as chimeras, will possess a mosaic of cells in all tissues, including the brain. When they mature, the mice will perform the kind of behavior according to the type of neurons which were inherited from the particular genetic strain. The origin of these neurons will be identified by immunocytochemical procedures. Thus, generating chimeras will enable him to identify the sets of neurons which are responsible for some genetically determined hormone-regulated behaviors. Such information eventually will help us locate and fix behavioral abnormalities which may arise congenitally, from disease, or accidentally.
