In terrestrial vertebrates, the sense of smell provides important information about the environment and enables the animals to detect food, avoid predators, and find mates. Odors are detected by the sensory neurons in the olfactory epithelia in the nose, which pass the information to the main olfactory bulb for further processing. The talk will be speaking on the neural circuitry in the olfactory system, its development in relation to the requirement of neural activity and how interfering with this circuitry can leads to abnormal behaviors in animals.