To distinguish colors, the brain compares signals from sensory cells that are activated by light of different wavelengths. But how does color information reach a fly’s brain? Insects possess compound eyes, which are composed of many individual eye units, so-called ommatidia.
To detect an object on the basis of color, flies use both inner and outer receptor cells of the innumerable ommatidia in the flies' compound eyes, as Bernstein scientists have now discovered.
Pavel Masek/Bernstein Koordinationsstelle, 2013
A single ommatidium consists of eight light-sensitive photoreceptor cells. Six of them are arranged in a ring, with the two remaining cells located in its center. In flies, the six outer receptor cells respond to light over a broad range of wavelengths. Since the perception of color depends on the processing of specific wavelength regions, researchers assumed that these receptors are mainly responsible for motion perception.
In contrast, the two inner photoreceptors are sensitive to light of single narrow wavelength regions—and may therefore pass on precise information about colors. So far, they have been considered to be the exclusive source of color vision in flies.
Neuroscientists at the Bernstein Center Munich, the Max Planck Institute of Neurobiology in Martinsried, and the LMU Munich now discovered that this assumption needs to be revised. "The outer photoreceptors contribute to color discrimination of the fly as well," explains Thomas Wachtler, one of the researchers involved in the study. Using a computer model, the biologists mimicked the processing of photoreceptor signals in the fly eye—and realized that the wavelength sensitivity of the outer photoreceptors must be taken into account in order to obtain the fly's color discrimination abilities.
To support their theoretical results with experimental data, the researchers selectively controlled photoreceptor function in genetically manipulated flies. In this way, they obtained flies that possessed only one of the two color-specific inner receptor cells besides the outer receptor cells. Yet, the flies were able to distinguish two colors. "This indicates that the brain draws on information from both inner and outer photoreceptors for the color comparison," explains Christopher Schnaitmann, first author of the study. The assumption was confirmed when the scientists inhibited the activity of nerve cells that convey signals from the outer receptor cells to the brain: the flies' ability to perceive color differences was severely impaired.
The outer photoreceptors thus seem to be true multitaskers, contributing to both motion and color vision in the fly. Their dual role makes sense in small animals: it ensures that despite a limited number of neurons, flies still have complex visual skills—and may easily distinguish a bread crumb from a dust grain.
The Bernstein Center Munich is part of the National Bernstein Network Computational Neuroscience in Germany. With this funding initiative, the German Federal Ministry of Education and Research (BMBF) has supported the new discipline of Computational Neuroscience since 2004 with over 170 million Euros. The network is named after the German physiologist Julius Bernstein (1835-1917).Contact:
Weitere Informationen:http://www.neuro.mpg.de/tanimoto website Hiromu Tanimoto
Mareike Kardinal | idw
Transport of molecular motors into cilia
28.03.2017 | Aarhus University
Asian dust providing key nutrients for California's giant sequoias
28.03.2017 | University of California - Riverside
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
29.03.2017 | Materials Sciences
29.03.2017 | Physics and Astronomy
29.03.2017 | Earth Sciences