Super Resolution Microscopy

Excitatory Synapses Revealed with STORM Synapses in the mouse brain (olfactory bulb) imaged using conventional fluorescence microscopy (left) or STORM (right). The red protein is the presynaptic scaffold Bassoon and the green protein is the postsynaptic scaffold Homer1.Courtesy of Zhuang lab

Excitatory Synapses Revealed with STORM

Synapses in the mouse brain (olfactory bulb) imaged using conventional fluorescence microscopy (left) or STORM (right). The red protein is the presynaptic scaffold Bassoon and the green protein is the postsynaptic scaffold Homer1.

Courtesy of Zhuang lab

Recent innovations in fluorescence-based light microscopy have made it possible to clearly visualize tiny biological structures that before could only be detected by more invasive imaging methods. These innovations have overcome what used to be one of the greatest limitations of light microscopy—the “diffraction-limited” resolution, or inability to see structures smaller than the wavelength of light itself.

One of the new techniques is STochastic Optical Reconstruction Microscopy (STORM), developed by theZhuang lab in 2006. The trick of STORM is to turn on a subset of fluorescent molecules at a time, so that the images of individual molecules are optically resolvable. The precise location of each molecule can then be determined by identifying the center of its image. By iterating this process many times for the same sample, it is possible to obtain multi-color 3D images with resolution down to a few tens of nanometers.

As part of the Conte Center’s Connectome project, the lab is using STORM to visualize the substructure of synapses in the brain. The focus is on the synapses of PV-cells in the prefrontal cortex, thought to be particularly important in the pathology of mental illness. The development of these synapses is being examined both in normal laboratory mice and mouse models of early life stress or mental illness.