Roles of microglia in the healthy brain

Published on May 31, 2022   36 min

A selection of talks on Neuroscience

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Hi, my name is Dr. Marie-Eve Tremblay. I am an associate professor at the Division of Medical Sciences, at the University of Victoria and Canada Research Chair in Neurobiology of Aging and Cognition. This presentation will provide an overview of the physiological roles of microglia in the healthy brain, with a technical and historical perspective.
As the provocative title of this review suggests, we are experiencing an important paradigm shift in the microglia field. Microglia are not neurotoxic cells that should be eradicated. Instead, they are beneficial immune cells that actively contribute through their many physiological roles in order to maintain brain health.
Over the past decade, the beneficial roles of microglia in the healthy brain have started to unravel, as shown by a PubMed search with microglia in the title in all fields. There were only few papers published on the topic before the 1990s, and then a steady increase until the beginning of our century, leading to an exponential growth of microglial research. There is the first inflection point in 2005, with the seminal discovery using non-invasive two-photon in vivo imaging, that microglia, which used to be called resting or quiescent in the healthy brain, are extremely dynamic. Continuously surveying the parenchyma with their highly motile processes. There is a second inflection point in 2010, coinciding with the discovery of their exclusive origin from the embryonic yolk site. Microglia infiltrate the brain during embryonic development and they stayed there throughout life, maintaining their numbers through self-renewal. For more information regarding the first description of microglia, I invite you to read the Translation, by Amanda Sierra, published in the journal, Glia, of the original work by Pio del Rio-Hortega, considered the Big-Bang of Modern Glial Biology Also, this recent review on Microglial History in Trends in Neurosciences.