Watching millions of neurons in the brain interacting with each other is the ultimate dream of neuroscientists! A new imaging method now makes it possible to observe the activation of large neural circuits, currently up to the size of a small-animal brain, in real time and three dimensions. Researchers at the Helmholtz Zentrum München and the Technical University of Munich have recently reported on their new findings in Nature’s journal ‘Light: Science & Applications’.
Nowadays it is well recognized that most brain functions may not be comprehended through inspection of single neurons. To advance meaningfully, neuroscientists need the ability to monitor the activity of millions of neurons, both individually and collectively. However, such observations were so far not possible due to the limited penetration depth of optical microscopy techniques into a living brain.
A team headed by Prof. Dr. Daniel Razansky, a group leader at the Institute of Biological and Molecular Imaging (IBMI), Helmholtz Zentrum München, and Professor of Molecular Imaging Engineering at the Technical University of Munich, has now found a way to address this challenge. The new method is based on the so-called optoacoustics*, which allows non-invasive interrogation of living tissues at centimeter scale depths.
”We discovered that optoacoustics can be made sensitive to the differences in calcium ion concentrations** resulting from neural activity and devised a rapid functional optoacoustic neuro-tomography (FONT) system that can simultaneously record signals from a very large number of neurons”, said Dr. Xosé Luis Deán-Ben, first author of the study. Experiments performed by the scientists in brains of adult zebrafish (Danio rerio) expressing genetically encoded calcium indicator GCaMP5G demonstrated, for the first time, the fundamental ability to directly track neural dynamics using optoacoustics while overcoming the longstanding penetration barrier of optical imaging in opaque brains. The technique was also able to trace neural activity during unrestrained motion of the animals.
Tracking the wildfire
"So far we demonstrated real-time analysis on whole brains of adult animals with roughly 2x3x4 millimeter dimensions (approximately 24 mm3)," says the study’s leader Razansky. State-of-the-art optical microscopy methods are currently limited to volumes well below a cubic millimeter when it comes to imaging of fast neural activity, according to the researchers. In addition, their FONT method is already capable of visualizing volumes of more than 1000 cubic millimeters with temporal resolution of 10 milliseconds.
Large-scale observation of neural activity is the key to understanding how the brain works, both under normal and diseased conditions. "Thanks to our method, one can now capture fast activity of millions of neurons simultaneously. Parallel neural networks with the social media: in the past, we were able to read along when someone (in this case, a nerve cell) placed a message with a neighbor. Now we can also see how this message spreads like wildfire," explains Razansky. "This new imaging tool is expected not only to significantly promote our knowledge on brain function and its pathophysiology but also accelerate development of novel therapies targeting neurological and neuropsychiatric disorders,” he concludes.
* Optoacoustics allows for high resolution, non-invasive, 3D imaging of living tissues. The technology uses short laser pulses that cause short-term expansion of the tissue, leading to tiny ultrasound vibrations. Those are registered with specially designed detectors, processed and converted into three-dimensional images of the interrogated tissue. To this end, the Helmholtz researchers have developed a number of optoacoustic imaging technologies for tracking hemodynamics and targeted agent delivery in a number of pre-clinical and medical imaging applications. The current work addresses significantly faster biological processes, such as neural activation.
** Nerve activation causes displacements of the calcium ions, which are transported in or out the neurons through so-called ion channels. Fluctuations in the intra-cellular calcium concentrations can be measured by means of genetically encoded calcium indicators (GECIs), which change their absorption spectrum, and consequently their color, depending on the amount of calcium present.
For his research, Razansky was awarded with highly competitive research grants from the European Research Council (ERC) and the US National Institutes of Health (NIH).
Deán-Ben, XL. et al. (2016): Functional optoacoustic neuro-tomography for scalable whole-brain monitoring of calcium indicators. Light: Science & Applications, doi:10.1038/lsa.2016.201
The Helmholtz Zentrum München, the German Research Center for Environmental Health, pursues the goal of developing personalized medical approaches for the prevention and therapy of major common diseases such as diabetes and lung diseases. To achieve this, it investigates the interaction of genetics, environmental factors and lifestyle. The Helmholtz Zentrum München is headquartered in Neuherberg in the north of Munich and has about 2,300 staff members. It is a member of the Helmholtz Association, a community of 18 scientific-technical and medical-biological research centers with a total of about 37,000 staff members. http://www.helmholtz-muenchen.de/en
The Institute for Biological and Medical Imaging (IBMI) conducts research into in vivo imaging technologies for the biosciences. It develops systems, theories and methods of imaging and image reconstruction as well as animal models to test new technologies at the biological, preclinical and clinical level. The aim is to provide innovative tools for biomedical laboratories, for diagnosis and for the therapeutic monitoring of human diseases. http://www.helmholtz-muenchen.de/ibmi
Technical University of Munich (TUM) is one of Europe’s leading research universities, with more than 500 professors, around 10,000 academic and non-academic staff, and 39,000 students. Its focus areas are the engineering sciences, natural sciences, life sciences and medicine, reinforced by schools of management and education. TUM acts as an entrepreneurial university that promotes talents and creates value for society. In that it profits from having strong partners in science and industry. It is represented worldwide with a campus in Singapore as well as offices in Beijing, Brussels, Cairo, Mumbai, San Francisco, and São Paulo. Nobel Prize winners and inventors such as Rudolf Diesel, Carl von Linde, and Rudolf Mößbauer have done research at TUM. In 2006 and 2012 it won recognition as a German "Excellence University." In international rankings, TUM regularly places among the best universities in Germany. http://www.tum.de/en/homepage
Contact for the media:
Department of Communication, Helmholtz Zentrum München - German Research Center for Environmental Health, Ingolstädter Landstr. 1, 85764 Neuherberg - Tel. +49 89 3187 2238 - Fax: +49 89 3187 3324 - E-mail: email@example.com
Scientific Contact at Helmholtz Zentrum München:
Prof. Dr. Daniel Razansky, Helmholtz Zentrum München - German Research Center for Environmental Health, Institute for Biological and Medical Imaging, Ingolstädter Landstr. 1, 85764 Neuherberg - Tel. +49 89 3187 1587, E-mail: firstname.lastname@example.org
https://www.helmholtz-muenchen.de/en/press-media/press-releases/2016/index.html - Find more press releases of Helmholtz Zentrum München here
Sonja Opitz | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs
16.01.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Cholera bacteria infect more effectively with a simple twist of shape
13.01.2017 | Princeton University
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
17.01.2017 | Earth Sciences
17.01.2017 | Materials Sciences
17.01.2017 | Architecture and Construction