Center for Microscopy and Image Analysis.
Image Analysis


Three image analysis workstations are available at the CMIA. A Metamorph 6.1 workstation is situated in room 406E. A workstation loaded with Image Pro Plus 5.1 and 3D constructor is situated in 406D and another is available at 406F. The later is also used to drive the digital camera. There is a full capacity available in the CMIA for opening and converting confocal images either as x/y/z stacks or time lapse. 3D constructor, represents a powerful software addition for 3D rendering from series of images. It has been mainly used with confocal images, but it has strong capacity for analysis of all kinds of image sequences as MRI. Although digital imaging is already well integrated in many scientific fields, a few investigators take a maximum advantage of the possibilities provided by this so promising approach. The major advantage of digital image is that it translates the information from your specimen into a number. If the images are taken under appropriate conditions, the may then be used for comparisons. However, one has to take into account limiting factors as optical resolution into the design of experiments. Careful design of the experiment is prerequisite for successful image analysis project. CMIA can assist investigators in all steps involved in this process, and to provide guidelines for the optimal experimental conditions.
Most common demands for image analysis are co-localizations. Now we have the ability to expand this demand at 3D. However, co-localization has to be very carefully considered. Automatic count of objects, their size and integrated optical brightness are among common demands of scientist. All these can be addressed efficiently with available at the CMIA resources for image analysis. You should not hesitate to ask the CMIA director about the existing capabilities, and how they can be integrated in your specific project.

In this experiment, biocytin has been used to label vestibular fibers and terminals in chick vestibular nucleus (revealed with Streptavidin/Alexa Fluor 647, blue) and anti synaptotagmin antibody has been used to label all synaptic terminals (vesicle integrated protein, Alexa Fluor 488 - red). The specific question of this project is whether the large axo-somatic terminals contain chemical synapses (B). Intensities for the red and blue channel are plotted along a line scan, which revealed the relationship between the two labels. As can bee seen on B, the line goes over one process of a large axo-somatic terminal and includes some other structures. C, is the intensity profile of this line scan with a small arrow showing the co-localization, or with a simple words, the region of the large terminals containing a cluster of synaptic vesicles. However as you can further see from this line scan, blue peaks are distinct from red peaks, which means that the two labels are in close relationship, but not overlap. In D, a simple co-localization, can reveal that most of the bulbous enlargements of the vestibular fibers also contain high levels of synaptic vesicle protein labeling, indicating their synaptic nature (arrows on D). In this particular case the pixel size measured about 300 nanometers with an approximate size of synaptic terminal of about 2 microns. With this large objects, co-localization is a good choice.
Another example from the same lab, at which the large axo-somatic terminals are labeled with biocytin (boxed region in A1), MAP2 immunolabeling (Alexa Fluor 488) has been used to visualize neurons. 3D reconstruction from series of confocal stacks revealed the relationship between the vestibular fibers and vestibular nuclei neurons. A2 and A3, show the large axo-somatic terminals in iso-surface mode which reveals the details of the structure.
The Center for Microscopy and Image Analysis, The George Washington University Medical Center, Ross Hall 406, 2300 I St NW, Washington DC 20037 Ph. 202.994.2881 Fax. 202.994.8885, anaasp@gwumc.edu