By automating and standardizing the process in which brain samples are divided into sections and then imaged sequentially at precise spatial orientations in two-photon microscopes, the team, led by Assoc. Prof. Pavel Osten and consisting of scientists from his CSHL lab and the Massachusetts Institute of Technology, has opened the door to making whole-brain mapping routine.
Specifically, says Osten, "the new technology should greatly facilitate the systematic study of neuroanatomy in mouse models of human brain disorders such as schizophrenia and autism."
The new technology, developed in concert with TissueVision of Cambridge, Mass. and reported on in a paper appearing online Jan. 15 in Nature Methods, is called Serial Two-Photon Tomography, or STP tomography. Tomography refers to any process (including the familiar CAT and PET scans used in medical diagnostics) that images an object section by section, by shooting penetrating waves through it. Computers powered by mathematical formulae reassemble the results to produce a three-dimensional rendering. Two-photon imaging is a type used in biology laboratories, particularly in conjunction with fluorescent biomarkers, which can be mobilized to illuminate specific cell types or other anatomical features. The two-photon method allows deeper optical penetration into the tissue being sampled than conventional confocal microscopy.
As Osten explains, STP tomography achieves high-throughput fluorescence imaging of whole mouse brains via robotic integration of the two fundamental steps -- tissue sectioning and fluorescence imaging. In their paper, his team reports on the results of several mouse-brain imaging experiments, which indicate the uses and sensitivity of the new tool. They conclude that it is sufficiently mature to be used in whole-brain mapping efforts such as the ongoing Allen Mouse Brain Atlas project.
One set of experiments tested the technology at different levels of resolution. At 10x magnification of brain tissue samples, they performed fast imaging "at a resolution sufficient to visualize the distribution and morphology of green-fluorescent protein-labeled neurons, including their dendrites and axons," Osten reports.
A full set of data, including final images, could be obtained by the team in 6.5 to 8.5 hours per brain, depending on the resolution. These sets each were comprised of 260 top-to-bottom, or coronal, slices of mouse brain tissue, which were assembled by computer into three-dimensional renderings themselves capable of a wide range of "warping," i.e., artificial manipulation, to reveal hidden structures and features.
"The technology is a practical one that can be used for scanning at various levels of resolution, ranging from 1 to 2 microns to less than a micron," Osten says. Scans at the highest resolution level take about 24 hours to collect. This makes possible an impressive saving of time, Osten says, compared to methods that are now in use. Using these, it would take an experienced technician about a week to collect a set of whole-brain images at high resolution, he noted.
"What is most exciting about this tool is its application in the study of mouse models of human illness, which we are already doing in my lab," Osten says. "We are focusing on making comparisons between different mouse models of schizophrenia and autism. Many susceptibility genes have been identified in both disorders – one recent estimate by Dr. Mike Wigler's team here at CSHL put the figure at over 250 for autism spectrum disorders, for instance. Dr. Alea Mills at CSHL has published a mouse model of one genetic aberration in autism – a region on chromosome 16 – and soon we will have tens of models, each showing a different aberration.
"We will want to compare these mice, and that is essentially why we designed STP tomography – to automate and standardize the process of collecting whole-brain images in which different cell-types or circuit tracings have been performed. This makes possible comparisons across different mouse models in an unbiased fashion."
"Serial two-photon tomography: an automated method for mouse brain imaging" appears online in Nature Methods on January 15, 2012. The authors are: Timothy Ragan, Lolahon R Kadiri, Kannan Umadevi Venkataraju, Karsten Bahlmann, Jason Sutin, Julian Taranda, Ignacio Arganda-Carreras, Yongsoo Kim, H Sebastian Seung and Pavel Osten. the paper can be obtained online at http://www.nature.com/nmeth/index.html
This research was supported by grants from: The Simons Foundation, The McKnight Foundation, the Howard Hughes Medical Institute, and the National Institutes of Health.
About Cold Spring Harbor Laboratory
Founded in 1890, Cold Spring Harbor Laboratory (CSHL) has shaped contemporary biomedical research and education with programs in cancer, neuroscience, plant biology and quantitative biology. CSHL is ranked number one in the world by Thomson Reuters for impact of its research in molecular biology and genetics. The Laboratory has been home to eight Nobel Prize winners. Today, CSHL's multidisciplinary scientific community is more than 350 scientists strong and its Meetings & Courses program hosts more than 11,000 scientists from around the world each year. Tens of thousands more benefit from the research, reviews, and ideas published in journals and books distributed internationally by CSHL Press. The Laboratory's education arm also includes a graduate school and programs for undergraduates as well as middle and high school students and teachers. CSHL is a private, not-for-profit institution on the north shore of Long Island. For more information, visit www.cshl.edu.
Peter Tarr | EurekAlert!
Faster detection of atrial fibrillation thanks to smartwatch
18.03.2019 | Universität Greifswald
A peek into lymph nodes
15.03.2019 | Tohoku University
DESY and MPSD scientists create high-order harmonics from solids with controlled polarization states, taking advantage of both crystal symmetry and attosecond electronic dynamics. The newly demonstrated technique might find intriguing applications in petahertz electronics and for spectroscopic studies of novel quantum materials.
The nonlinear process of high-order harmonic generation (HHG) in gases is one of the cornerstones of attosecond science (an attosecond is a billionth of a...
Nano- and microtechnology are promising candidates not only for medical applications such as drug delivery but also for the creation of little robots or flexible integrated sensors. Scientists from the Max Planck Institute for Polymer Research (MPI-P) have created magnetic microparticles, with a newly developed method, that could pave the way for building micro-motors or guiding drugs in the human body to a target, like a tumor. The preparation of such structures as well as their remote-control can be regulated using magnetic fields and therefore can find application in an array of domains.
The magnetic properties of a material control how this material responds to the presence of a magnetic field. Iron oxide is the main component of rust but also...
Due to the special arrangement of its molecules, a new coating made of corn starch is able to repair small scratches by itself through heat: The cross-linking via ring-shaped molecules makes the material mobile, so that it compensates for the scratches and these disappear again.
Superficial micro-scratches on the car body or on other high-gloss surfaces are harmless, but annoying. Especially in the luxury segment such surfaces are...
The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.
A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...
Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.
"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...
11.03.2019 | Event News
01.03.2019 | Event News
28.02.2019 | Event News
22.03.2019 | Life Sciences
22.03.2019 | Life Sciences
22.03.2019 | Information Technology