As anyone whose nerves have been jangled by a babys howl or who have been riveted by the sight of an attractive person knows, nature has evolved sensory systems to be exquisitely tuned to relevant input. A major question in neurobiology is how neurons tune the strength of their interconnections to optimally respond to such inputs.
Neuronal circuitry consists of a web of neurons, each triggering others by launching bursts of neurotransmitters at targets on receiving neurons to produce nerve impulses in those targets. Neurons adjust the strength of those connections adaptively, to amplify or suppress connections. Some four decades ago, a general principle called the "efficient coding hypothesis" was formulated, holding that sensory systems adjust to efficiently represent the complex, dynamic sounds, sights, and other sensory input from the environment.
Writing in the August 4, 2005, issue of Neuron, researchers led by Christian K. Machens of Cold Spring Harbor Laboratory and Andreas Herz of Humboldt-University Berlin describe experiments with grasshopper auditory neurons that reveal new details of such sensory coding. Their findings show that "optimal stimulus ensembles" that trigger the neurons differ from those the grasshopper hears in the natural environment but largely overlap with components of natural sounds found in mating and mate-location calls.
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For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
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13.07.2018 | Life Sciences