Mice with this mutation show a similar type of social impairment and cognitive enhancement as the type seen in some people with autism spectrum disorders (ASDs). ASDs are enigmatic cognitive disorders that impair a patient's social interactions, but do not necessarily limit their intelligence.
The scientists said the mice they developed may represent an important advance in modeling autism spectrum disorders in mice and offer researchers a new tool for understanding how specific defects in neural development may lead to autism.
Howard Hughes Medical Institute investigator Thomas Südhof and his colleagues at the University of Texas Southwestern Medical Center published their findings September 6, 2007, in Science Express, which provides electronic publication of selected Science papers ahead of print.
The researchers engineered mice that have a single mutation in the gene for a protein called neuroligin-3. This protein functions as a cell adhesion molecule in synapses, the junctions that connect neurons in the brain and allow them to communicate with each other. Synapses are essential to all brain activities, such as perception, behavior, memory, and thinking. Südhof said that the neuroligin-3 mutation that his team recapitulated in the mice has been identified in some people with genetic conditions known as autism spectrum disorders (ASDs). Mutations in proteins that interact with neuroligin-3 have also been detected in some people with ASDs.
Proper function of the brain’s neuronal networks depends on a delicate balance between excitatory and inhibitory electrophysiological signaling among neurons. Südhof and his colleagues found that this balance was disrupted in the mutant mice, which also showed an increase in the signaling of inhibitory neurotransmitters. In contrast, they found that knocking out the neurologin-3 gene entirely produced no such imbalance.
The most striking behavioral abnormality they observed in the mutant mice was an impaired ability to interact socially with other mice. However, the animals showed enhanced spatial learning and memory—and were more able than normal mice to learn and to remember the location of a platform submerged in murky water.
“This combination of electrophysiological and behavioral effects is quite remarkable,” said Südhof. “It was also significant that these mice did not exhibit any other impairment of nervous system function – there was no abnormal locomotor activity or motor coordination, for example. This was a selective change, with social impairment on the one hand, yet cognitive enhancement on the other.”
Südhof said the mutant mice he and his colleagues developed potentially offer major advantages over other mouse models of ASDs. “In mouse models of autism that I am aware of, the autistic symptoms are only one minor part of the overall disease,” he said. “For example, autistic symptoms are only one component of mouse models of Fragile X syndrome.
“What sets this mouse model apart is that the mouse shows highly selective social deficits and memory enhancement, but as far as we can tell, no other pathologies. This makes it a potentially useful model for a subset of people with ASDs with just such characteristics,” he said.
Südhof his colleagues will use the mouse model to ask additional questions about the role that neuroligin proteins play in neural function and in ASDs. “We can also use these mice to study how these autistic symptoms—loss of social ability and enhanced memory—arise from the increase in inhibitory neurotransmission,” he said. “The key to understanding this mechanism will be in finding out what parts of the brain are responsible for these characteristics. And with this mouse model, we can identify precisely where the mutation acts in the brain.”
Jim Keeley | EurekAlert!
Bacteria as pacemaker for the intestine
22.11.2017 | Christian-Albrechts-Universität zu Kiel
Researchers identify how bacterium survives in oxygen-poor environments
22.11.2017 | Columbia University
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
22.11.2017 | Business and Finance
22.11.2017 | Physics and Astronomy
22.11.2017 | Physics and Astronomy