The classical way of studying biological material in a light microscope is to fix and stain the specimen and then to cut it up into thin slices for examination in the microscope. However, if thick slices or whole-mounts are examined, structures in the interior of the specimen are usually obscured by interference from structures at either side of the plane of focus. Optical sectioning techniques have been developed to minimize or eliminate this out-of-focus interference and enable the examination of whole-mount samples, thereby allowing visualization of the internal three-dimensional structure of living tissue.
Types of optical sectioning
- Computational optical sectioning (deconvolution)
- Laser scanning confocal imaging
- Differential interference contrast (Nomarski) microscopy
- Multiple-photon excitation fluorescence imaging