How the brain's nerve circuits can overlap but not get tangled
Untangling two impossibly intertwined sets of headphones at the bottom of your bag is maddening. Ideally, they wouldn’t get tangled in the first place, which is why inside the brain, where wiry networks of brain cells interweave, there are mechanisms to keep things in order. Two parallel networks of neurons process spatial and object-based information. Researchers interested in how these networks develop without disturbing each other analysed growth in the mouse brain. They found two molecules on the surface of cells (yellow and blue in the mouse brain section pictured) guide growth and prevent confusion. Each repels their counterpart's targets, while one actively attracts the neurons it aims to join, thus ensuring two separate networks form without any unwanted crossover. This cooperative attraction and repulsion helps each individual strand find its target, eventually constructing precise networks in the brain, where any misstep can have serious consequences.
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