动物实验 z-bo 2020-08-25 603

　　Colombian scientists have discovered a key feature of the brain's global positioning system that can help mice find what it is seeking. This research allows scientists to determine the precise role of cells in a specific area of the hippocampus, which is the brain's learning and memory center. The research also puts forward a long-term pursuit in the field of neuroscience: as information travels through the brain, tracking the path of information travels.

　　The author published these findings in the journal Neuron.

　　The senior author of this article, an associate professor in the Department of Neuroscience at Columbia University Medical Center (CUMC), and a principal investigator of the Mortimer B. Zuckerman Institute for Brain Behavior at Columbia University, PhD, MD, Attila Losonczy said: "Here In this study, our goal is to simulate what our brain is doing when we wander aimlessly on the street. In contrast, our brain reacts when we discover a unique dress." "By using a powerful two-photon microscope, we were able to observe the activity of individual cells in the hippocampus of mice, and then link the relationship between cell activity and specific behaviors—under this behavior, navigation and positioning—in a few years. Previously, this technical expertise was simply impossible to achieve."

　　The hippocampus can be divided into different areas to form an interconnected circuit through which information related to memory is processed. In this research, Dr. Losonczy and his team focused on the main output node of the hippocampus, CA1 area, which is the location of the code discovered by scientists-this work won the 2014 Nobel Prize.

　　A PhD candidate in the Department of Neuroscience at Columbia University Medical Center and the first author of this article, Nathan Danielson said: "We already know that the CA1 area can be divided into two different cell layers: deep and shallow." "Scientists want to know whether this division is to show that the two layers actually have different purposes in learning and memory. But no one has tested it, so we decided to observe."

　　To study these cells, the researchers placed mice on treadmills with different colors, characteristics, and odors, and used a two-photon microscope to detect the cell activity in the CA1 area. Then, the mice performed the following two tasks.

　　In the first task, the mouse runs on a treadmill and can experience different sights and sounds, some familiar and other new sights and sounds. In the second task, mice were given the task of finding water rewards, which were placed in a unique unmarked place along the treadmill. The members of the research team repeated these experiments during several learning sessions and monitored how each cell layer responded to different types of learning.

　　When the mouse performed the first task, the cells in the superficial cell layer of the CA1 area seemed to create an internal map, which remained basically unchanged from one period of learning to another. By comparison, the deep cells form an internal map with more dynamic changes—in fact, in each learning process, a different form of map is redrawn.

　　However, during the second test, when the mouse needs to learn the hidden reward position, the images of the deep cells are significantly more stable and less dynamic than the first task. Scientists have also discovered that deep cell activity is closely related to the ability of animals to discover rewards. The author believes that the distinction between cell layers means two different important processes for seeking navigation.

　　Danielson said: "If you are walking down the street looking for something special-say, your favorite restaurant-generally speaking, your brain first needs a map of the neighborhood." He continued, but for Finding a unique restaurant and arriving at that special location, the brain will also be divided into importance or prominence.

　　Danielson said: "In this sense, it is the way the brain uses a huge X mark on the map." "So when you look for that restaurant, you need both a map and this X mark. Our results show that in the brain, these different types of information can be conveyed through different cell layers in the CA1 area."

　　Dr. Losonczy added: "And, if you want to visit a new place after a month, the deep cell will update the route map, effectively marking the new location, and the basic nearby created by the shallow cell The map will remain relatively unchanged."

　　In response to Dr. Losonczy's words, this research shows an ingenious way that the basic structure of the brain allows it to complete a special type of navigation.

　　He said: “It’s amazing that the ability to navigate to a desired location can be so accurately represented in the structure of the hippocampus

　　, this is a very complicated feat. "" And it is even more shocking that we can now witness it happen in real time. "