New laser light technique fluoresces mouse brains for science

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Light-sheet based microscopy (LSM) is now illuminating fluorescent mouse brains to help scientists one day study neurological conditions such as autism and ischemic stroke.

LSM involves illuminating a biological sample with a thin sheet of light that is provided by a laser beam narrowed to just a few microns. The light is aimed at the sample’s side rather than from above or below, as with traditional light sources. Fluorescence emitted by the illuminated sample radiates upward through a lens, gets focused and is captured by a digital camera.

‘Our system combines the best feature of one microscopy technique — high-speed, single-plane imaging of multiple sections of a sample — with a second method that eliminates the accompanying problem of scattered background light leading to blurriness,’ said Francesco Pavone, a professor at the European Laboratory for Non-Linear Spectroscopy and leader of the team of six Italian research agencies that investigated LSM. Pavone’s multi-agency team’s work has been published in the latest issue of the peer reviewed Optical Society’s (OSA) open-access journal Optics Express.

In principle, this LSM technique should be applicable to human brain samples if the current obstacle of fluorescently staining large blocks of fixed tissue can be overcome. Because the light sheet illuminates the sample in the same plane, only a single section of the target is imaged at a time. Raising and lowering the illumination plane, as well as rotating the sample rapidly produces a series of two-dimensional sectional views known as slices that can yield a three dimensional map of a whole organism or any of its organs or systems. Embryos could also one day be studied with this technique.