大脑弹性 z-bo 2020-10-16 297

　　When the plasticity of neural connections is maximized and the development of the brain gradually begins to adapt to the environment, the key stage of neuron development is in the limited stage of life. Researchers at the Pisa Normal University and the Leibniz Institute of Aging (FLI) in Jena discovered the role of small microRNAs (miR-29) in these learning-dependent plastic steps. Studies have shown that the early rise of miR-29 levels in young mice can prevent cortical plasticity, and the blockade of miR-29 in adult animals can induce classical plasticity at an early stage. The above results indicate that miR-29 is an age-dependent modulator of developmental plasticity.

　　"In the sensitive developmental stage, the neural network of the visual cortex adapts to visual stimuli to the greatest extent and can identify key regulators of brain plasticity," this research was found in the EMBO report journal SNS. It was published by Professor Alessandro Cellerino. Say. The authors of this study are the team leader of Jena FLI, Professor Tommaso Pizzorusso of the University of Florence and the NRC Neuroscience Institute in Pisa.

　　Professor Cellerino explained: “The visual cortex circuit is a part of the visual system that can realize vision. It shows strong plasticity in the early stage, and then stabilizes it through molecular braking, limiting the critical link later, but from development to adulthood. During the transition to this stage, the underlying mechanisms that regulate the expression of these factors are still unclear.

　　In order to determine the factors that regulate the postpartum development of the visual cortex, the research team studied the visual cortex of mice. They analyzed the developing miRNA/RNA data set and compared them at different times: P10, which is the 10th day after birth, that is, the 10th day before the opening of the eyes and the sensitive period, the mouse cortex functions normally.

　　Their results indicate that the microRNA family miR-29 is an age-dependent regulator of the plasticity of visual cortex development. Professor Cellerino of FLI/SNS said: “miR-29a is increased by 30 times and is the most expressed miRNA during sensitive periods.” In fish, mice and humans, the regulation of the miR-29 family is very conservative. In addition, more than half of the targets regulated by miR-29 are down-regulated with age, including major regulators of brain plasticity. This indicates that miR-29a is an important regulator for downstream development. Further analysis showed that the premature increase in miR-29a concentration in young mice prevented major plasticity and led to the emergence of early neural networks (PPN). PPN is a special structure of the central nervous system, which is related to the synaptic stability of the adult brain. In both the developing and adult brains, they play an important role in disrupting plasticity and maintaining existing connections between nerve cells. In addition, the researchers found that blocking miR-29a in adult animals can reverse the developmental down-regulation of miR-29a targets, with typical plastic physiological and molecular characteristics in the sensitive stage. We have shown that it can induce a kind of plasticity of the eyeball. All in all, studies have shown that miR-29a is an important regulator of plastic failure and can promote the stability of visual cortex connections. The observation that miR29a is a remodeler of mature neural networks opens up new promising therapeutic prospects for miR-29a and other miR-29 family members to promote brain plasticity during aging and brain injury regeneration.