动物实验 z-bo 2020-09-01 348

　　Exercise and visual stimulation help to restore vision quickly

　　Unning helps mice who are blind due to early sensory deprivation restore their vision. Research also shows that the brain has the ability to respond to experience by remodeling itself, and neuroscientists believe that plasticity is the basis for learning.

　　More than fifty years ago, neurophysiologists David Hubel and Torsten Wiesel revealed the secret of transmitting information from the eyes to the brain. In addition, it has also been shown that the visual cortex can only develop normally by inputting information from the eyes at an early stage. If you look at one eye during the "critical period", it will develop amblyopia (almost blindness). This may happen if your eyelids, cataracts or other diseases are not corrected in time. Even if the eyes are opened during adulthood, vision recovery may be slow or incomplete.

　　In 2010, neuroscientists Christopheriell and Michael Stryker of the University of California, San Francisco showed that when running, neurons in the mouse visual cortex doubled their response to visual stimuli the above. Stryker said that at high speeds, it is more important to pay close attention to environmental movement and consume more energy. The need for quietness is not very high, which reduces response but saves energy. "When you are moving fast, the visual system is in a high gain state, because your eyes can tell you things far away, while touch can only tell you things nearby. No," Stryker said.

　　People usually think that activity stimulates plasticity. Therefore, Stryker of the University of San Francisco and colleague Megumi Kaneko hope to test whether running affects the plasticity of the visual cortex. it is. At a critical moment of vision development, they stitched up one eye of a mouse and caused amblyopia in the mouse. Then they opened their eyes again and divided them into two groups. A group of mice was exposed to the "noisy" image mode for 3 weeks on a treadmill for 4 hours a day. This visual mode is used to activate almost all the main visual cortex cells in mice. The researchers recorded the brain activity of mice using endogenous signal imaging techniques similar to magnetic resonance. After one week, the visual cortex of the eye area of these mice showed better sensitivity. After two weeks, the sensitivity is comparable to normal mice without blindness. The other control group with no visual stimulation in the cage had a slower response to eyes that had been sealed and could not reach the normal response level. Further experiments have shown that running or visual stimulation alone will not produce such an effect. And vision can only be restored under certain stimuli. During rehabilitation training, the mice in the "noisy" image mode could not significantly improve their response to band movement. vice versa. The results showed that only the vision circuit was activated during recovery from driving.

　　"This shows that the phenomena we observed are very reliable," said Massimo Scanziani, a neurobiologist at the University of California, San Diego. "The conclusion is clear and repeatable. This is an ideal choice for further study of the mechanism behind the phenomenon."

　　Stryker and his colleagues are now checking whether their findings affect humans.