[Show abstract][Hide abstract] ABSTRACT: Ultramicroscopy is a powerful tool to reveal detailed three-dimensional structures of large microscopical objects. Using high magnification, we observed that formalin induces fluorescence more in extra-cellular space and stains cellular structures negatively, rendering cells as dark objects in front of a bright background. Here, we show this effect on a three-dimensional image stack of a hippocampus sample, focusing on the CA1 region. This method, called FIF-Ultramicroscopy, allows for the three-dimensional observation of cellular structures in various tissue types without complicated staining techniques.
PLoS ONE 01/2010; 5(4):e10391. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In a recent publication we described a microscopical technique called Ultramicroscopy, combined with a histological procedure that makes biological samples transparent. With this combination we can gather three-dimensional image data of large biological samples. Here we present the theoretical analysis of the z-resolution. By analyzing the cross-section of the illuminating sheet of light we derive resolution values according to the Rayleigh-criterion. Next we investigate the resolution adjacent to the focal point of the illumination beam, analyze throughout what extend the illumination beam is of acceptable sharpness and investigate the resolution improvements caused by the objective lens. Finally we conclude with a useful rule for the sampling rates. These findings are of practical importance for researchers working with Ultramicroscopy to decide on adequate sampling rates. They are also necessary to modify deconvolution techniques to gain further image improvements.
PLoS ONE 02/2009; 4(6):e5785. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Visualizing entire neuronal networks for analysis in the intact brain has been impossible up to now. Techniques like computer tomography or magnetic resonance imaging (MRI) do not yield cellular resolution, and mechanical slicing procedures are insufficient to achieve high-resolution reconstructions in three dimensions. Here we present an approach that allows imaging of whole fixed mouse brains. We modified 'ultramicroscopy' by combining it with a special procedure to clear tissue. We show that this new technique allows optical sectioning of fixed mouse brains with cellular resolution and can be used to detect single GFP-labeled neurons in excised mouse hippocampi. We obtained three-dimensional (3D) images of dendritic trees and spines of populations of CA1 neurons in isolated hippocampi. Also in fruit flies and in mouse embryos, we were able to visualize details of the anatomy by imaging autofluorescence. Our method is ideally suited for high-throughput phenotype screening of transgenic mice and thus will benefit the investigation of disease models.
[Show abstract][Hide abstract] ABSTRACT: Ultramicroscopy, a novel optical tomographic imaging modality related to fluorescence microscopy, allows to acquire cross-sectional slices of small specially prepared biological samples with astounding quality and resolution. However, scattering of the fluorescence light causes the quality to decrease proportional to the depth of the currently imaged plane. Scattering and beam thickness of the excitation laser light cause additional image degradation. We perform a physical simulation of the light scattering in order to define a quantitative function of image quality with respect to depth. This allows us to establish 3D-volumes of quality information in addition to the image data. Volumes are acquired at different orientations of the sample, hence providing complementary regions of high quality. We propose an algorithm for rigid 3D-3D registration of these volumes incorporating voxel quality information, based on maximizing an adapted linear correlation term. The quality ratio of the images is then used, along with the registration result, to create improved volumes of the imaged object. The methods are applied on acquisitions of a mouse brain and mouse embryo to create outstanding three-dimensional reconstructions.
Medical image computing and computer-assisted intervention : MICCAI ... International Conference on Medical Image Computing and Computer-Assisted Intervention. 02/2007; 10(Pt 2):718-25.