Neuron Imaging -Increasing Resolution Threefold

Scientists are continuously refining tools to better delineate the details of the brain's cellular workings. One method of capturing extremely small aspects of brain cells is by using two-photon microscopy. This type of device can pick up minutiae that other scanners like magnetic resonance can't. Now researchers have increased the resolution of this imaging modality by threefold. They have combined stimulated emission depletion microscopy with the two-photon microscopy in order to gain this ability. This new method will enable them to see things like dendritic spines on neurons with more clarity than ever before. This will lead to a better understanding of how the connections between neurons function and change over time.

With conventional microscope lenses there is something called the "diffraction limit". This limit means that light can not be focused to less than half of its wavelength. However, researchers have found many news ways of circumventing this limit. Stimulated emission depletion (STED) microscopy is one of the first methods that overcame this limit. Researchers are continuing to better focus light so as to characterize smaller cellular features. Recently scientists have been able to focus light to 20 times smaller than its normal wavelength. In the future, the researchers hope to shrink light so it is comparable to the size of an electron's wavelength. An electron is an elementary particle that is much smaller than a single atom. Electron microscopes use beams of electrons for imaging purposes and have extremely high resolving power. The only problem is that they can't be used on live tissue, while light based microscopes can.

The researchers who have combined the 2-photon with the STED microscopy believe that they can already increase the resolution another threefold. This would be done by exactly timing the pulse of the depletion light. I think there will be a push to incorporate newer technologies to allow for even better resolving power in the future. This will lead to an improved understanding of how the brain functions at a sub-cellular level.