[ad_1]
If you park your car in the office car park in the morning, you usually have no trouble finding it at the end of the day. The next day you can park a few places further. But even tonight, you will find your car, even if the memories are very similar both days. We do this because our brain is able to store very similar event memories in the form of different memories, thanks to so-called model separation. Researchers at the Institute of Science and Technology of Austria (IST Austria) are figuring out how the brain calculates this model separation in a region of the brain called the dentate gyrus. The results of his work are published today in the journal Nature Communications.
Peter Jonas and his team, including Claudia Espinoza, first author and PhD student, Jose Guzman, former Jonas Fellowship Fellow and now IMBA Scientific Collaborator, and Xiaomin Zhang, currently Jonas Fellowship Fellow, used mice to understand how connections between neurons allow the dentate gyrus, part of the hippocampus, to separate the patterns.
In the dentate gyrus, two types of neurons send signals: the main neurons send excitatory signals, while the interneurons send inhibitory signals. The researchers have tried to decipher the connectivity rules between neurons: which neurons transmit signals, are the connections between neurons reciprocal or even mutual, or do many neurons converge so that they send their neurons? signals to a neuron? Researchers have captured signals between neurons to understand how neurons are connected and how the local circuit supports pattern separation. Espinoza performed a complete cellular imaging of eight neurons. In these shots, she stimulated a neuron in the dentate gyrus and recorded the reaction of the other seven neurons. By marking all stimulated neurons, she was then able to reconstruct the morphology of the circuit.
The researchers found that a group of interneurons, interneurons expressing parvalbumin, are only bound in a particular way in the dentate gyrus. In the dentate, interneurons expressing parvalbumin gyrus primarily inhibit the activity of neighboring neurons. This phenomenon is also called lateral inhibition. In other areas of the brain, such as the neocortex, interneurons expressing parvalbumin are not bound in this way. "We believe that the unique connectivity rules of interneurons expressing parvalbumin, eg lateral inhibition, an adaptation to the specific network function of this region of the brain," explains Claudia Espinoza. "Our experimental data supports the idea that the separation of the forms works according to a mechanism called the winner takes all, so the winner takes all.The lateral inhibition in the dentate gyrus causes this mechanism. Has not been proven, we need behavioral data and computer modeling that we are working on. "
Once the dentate gyrus has separated similar memories to avoid overlap, the CA3 region of the hippocampus stores these memories. In a 2016 study in the journal Science, Peter Jonas and Jose Guzman showed that connectivity in the CA3 region of the hippocampus is well suited to retrieve information as part of a process called completion of the pattern . "At the biological level, our group found the connectivity rules that support the function of calculating a brain region," says Espinoza. "Our work helps to show how local circuits are optimized for the specific function of a brain zone.While the signals that reach the dentate gyrus are important, the way the dentate gyrus calculates this information to obtain a separation of reasons is crucial. "
Claudia Espinoza is a PhD student in Peter Jonas' group. Before Claudia Espinoza came to IST Austria in 2013 for her doctoral dissertation, she had worked with patients with neurological diseases. This experience motivated Espinoza to pursue a doctorate in neuroscience: "I realized that my work as a therapist was very limited because the treatment we could offer our patients was very limited.In fact, most of the available treatments are soothing The main reason is that the information on the functioning of the nervous system is limited and more limited than most people believe.This fact motivated me the most to change my career as a researcher. think that knowledge creation is a great way to contribute to our society and indirectly help people. "The IST Austria Interdisciplinary Graduate School offers fully funded doctoral positions in the natural sciences and mathematics. Applications for the next academic year at the Graduate School IST Austria begin in mid-October: phd.ist.ac.at
About IST Austria
The Institute of Science and Technology (IST Austria) in Klosterneuburg is a research institute with its own doctoral law. Opened in 2009, the institute is dedicated to basic research in the natural sciences, mathematics and computer science. The institute employs professors according to a tenure track model and post-docs, as well as doctoral students in an international doctoral school. In addition to its commitment to the principle of basic research, which relies solely on scientific curiosity, the Institute holds the rights over all the discoveries that result and promotes their exploitation. The first president is Thomas Henzinger, renowned computer scientist and former professor at the University of California at Berkeley (United States) and at EPFL in Lausanne. http://www.ist.ac.at
scientific contact:
Peter Jonas
[email protected]
Original publication:
Claudia Espinoza, Jose Guzman, Xiaomin Zhang and Peter Jonas, Nature Communications, 2018, DOI: 10.1038 / s41467-018-06899-3 "Parvalbumin + interneurons obey unique connectivity rules and establish a potent microcircuit of inhibition Lateral in the dentate gyrus
idw 2018/11
Source link
