Left-right differences in the adult human brain have been noted for over 150 years. However, the way in which brain asymmetry is established during fetal development is not well understood. Reduced or reversed brain asymmetry have been linked to many psychiatric disorders, including schizophrenia, autism, depression, and dyslexia.
The Gamse laboratory is identifying and studying genes that control how such left-right asymmetries develop in the vertebrate brain. They use the zebrafish as a model organism for these studies. Zebrafish embryos have many advantages for investigating brain laterality, as they are transparent, develop rapidly, and have prominent left-right differences in the brain, particularly in a region known as the epithalamus. Gamse lab members have identified genes that control the formation of brain asymmetry by looking for mutant versions of these genes that cause defects in epithalamic laterality. These genes, and the consequences of their mutation, have revealed a series of embryonic events that lead to left-right asymmetry. These include migration of neurons from the center of the brain towards one side, and elaboration of different neuronal morphology on the left versus the right side. The lab is continuing to identify new laterality genes through forward and reverse genetic methods, in an effort to comprehensively describe the formation of asymmetry in the epithalamus.