A brief history of time-lapse.

Time-lapse is used for imaging the dynamics of living cells and tissues with the light microscope. The technique involves recording a single microscope field at intervals of lapsed time, along with keeping the specimen alive and in good health on the microscope stage throughout the experiment. When the full sequence of images is subsequently played back as a movie, the event is speeded up in proportion to the interval between frames. A structure that appears unremarkable in a still image can take on a new identity when a sequence of the images is played back as a time-lapse movie. For example, when cells are imaged using fluorescent speckle microscopy (25), they appear as a series of bright dots (speckles) in still images. The speckles take on a new identity when viewed as a timelapse movie; for example, the speckles may line up in the case of fluorescently labeled microtubules (25), or they may move together in the case of fluorescently labeled actin (24).