The latest issue of the journal Science (November 5) signifies a significant shift in brain research. This development is intriguing, not just for the abundance of new details regarding how the brain works and fails in mental and neurological disorders, but also as a rare instance of a scientific discipline changing direction. Such shifts are often noted in scientific history, yet we seldom get to see these critical moments in real-time.
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The journal Science is a leading international publication that covers various scientific fields; this particular issue includes a special feature on glia. In contrast to neurons, glia are brain cells that do not produce electrical impulses, and they comprise a significant portion—85 percent—of brain cells. Despite their numbers, they have received little attention over the past century. I refer to this emerging area of neuroscience as "The Other Brain," as we are just beginning to investigate its functions. The new discoveries are broadening our understanding of how information is processed in the brain, rapidly driving advancements in treatments for conditions like spinal cord injuries, brain cancer, chronic pain, and Alzheimer's disease. They challenge a century's worth of traditional beliefs about the brain's fundamental principles.
Historically, glia were perceived merely as supportive cells for neurons, responsible for nourishing them and cleaning up after them, and responding to brain injuries. Their roles were viewed as secondary to the more intriguing functions of neurons in information processing and memory storage. Consequently, glial research struggled to secure funding in the highly competitive realm of brain science. There was a lack of training in glial science for neuroscientists, and most standard texts barely touched on glia. Major journals had editors who were unfamiliar with these complex brain cells. As a result, research on glia rarely found its way into prominent scientific publications, hampering the progress of glial researchers for decades. However, this is now undergoing a transformation.
Glia's functions can be generally categorized into three broad areas, and there are four distinct types of glia that fulfill these roles. Astrocytes, glia named for their star-like shape, occupy the gaps between neurons. They supply energy to neurons, regulate the chemical environment around them within narrow limits essential for their survival and electrical firing, and facilitate communication at synapses.
