Synaptic connections are formed during development but are continually modified through experience and learning and memory. Any alteration to the normal connectivity leads to behavioral and cognitive changes that underlies psychological and neurodegenerative disorders. Therefore, understanding how functional networks of synaptic connections are established is critical for gaining insights into normal brain function. A mutant screen for defects in synapse in Drosophila has led to the discovery of a mutant line that shows aberrant synapse formation. Named as baha (bad hair day), homozygous mutant photoreceptors and motor neurons project to their correct target area in early developmental stages but subsequently fail to maintain contacts or form mature and functional synapses. Preliminary work thus suggests that baha may function as a critical factor in synapse formation. To investigate baha's role in synaptogenesis, I propose to perform further characterization of its synaptic phenotype, to identify and clone the baha gene, and to investigate the molecular mechanisms of its action. Cloning and characterization of baha gene may thus lead to identification of components of synapse formation, a process that remains poorly understood.