"The dynamic nature of the brain operates at disparate time scales ranging from milliseconds to months. How do single neurons change over such long time scales? This question remains stubborn to answer in the field of brain plasticity mainly because of limited tools to study the physiology of single neurons over time in the complex environment of the brain. The research aim of this proposal is to reveal the physiological changes of single neurons in the mammalian brain over disparate time scales using time-lapse optical imaging. Specifically, we aim to establish a new team that will develop genetic and optical tools to probe the physiological activity of single neurons, in vivo. As a model system, we will study a unique neuronal population in the mammalian brain; the adult-born local neurons in the olfactory bulb. These neurons have tremendous potential to reveal how neurons develop and maintain in the intact brain because they are accessible both genetically and optically. By following the behavior of adult-born neurons in vivo we will discover how neurons mature and maintain over days and weeks. If our objectives will be met, this study has the potential to significantly ""raise the bar"" on how neuronal plasticity is studied and reveal some basic secrets of the ever changing mammalian brain."