This Is What Your Brain Does When You’re Not Doing Anything

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The original version of this story appeared in Quanta Magazine.

Whenever you’re actively performing a task—say, lifting weights astatine nan gym aliases taking a difficult exam—the parts of your encephalon required to transportation it retired go “active” erstwhile neurons measurement up their electrical activity. But is your encephalon progressive moreover erstwhile you’re zoning retired connected nan couch?

The answer, researchers person found, is yes. Over nan past 2 decades they’ve defined what’s known arsenic nan default mode network, a postulation of seemingly unrelated areas of nan encephalon that activate erstwhile you’re not doing overmuch astatine all. Its find has offered insights into really nan encephalon functions extracurricular of well-defined tasks and has besides prompted investigation into nan domiciled of encephalon networks—not conscionable encephalon regions—in managing our soul experience.

In nan precocious 20th century, neuroscientists began utilizing caller techniques to return images of people’s brains arsenic they performed tasks successful scanning machines. As expected, activity successful definite encephalon areas accrued during tasks—and to nan researchers’ surprise, activity successful different encephalon areas declined simultaneously. The neuroscientists were intrigued that during a wide assortment of tasks, nan very aforesaid encephalon areas consistently dialed backmost their activity.

It was arsenic if these areas had been progressive erstwhile nan personification wasn’t doing anything, and past turned disconnected erstwhile nan mind had to ore connected thing external.

Researchers called these areas “task negative.” When they were first identified, Marcus Raichle, a neurologist astatine nan Washington University School of Medicine successful St. Louis, suspected that these task-negative areas play an important domiciled successful nan resting mind. “This raised nan mobility of ‘What’s baseline encephalon activity?’” Raichle recalled. In an experiment, he asked group successful scanners to adjacent their eyes and simply fto their minds rotation while he measured their encephalon activity.

He recovered that during rest, erstwhile we move mentally inward, task-negative areas usage much power than nan remainder of nan brain. In a 2001 paper, he dubbed this activity “a default mode of encephalon function.” Two years later, aft generating higher-resolution data, a squad from nan Stanford University School of Medicine discovered that this task-negative activity defines a coherent web of interacting encephalon regions, which they called the default mode network.

The find of nan default mode web ignited curiosity among neuroscientists astir what nan encephalon is doing successful nan absence of an outward-focused task. Although immoderate researchers believed that nan network’s main usability was to make our acquisition of mind wandering aliases daydreaming, location were plentifulness of different conjectures. Maybe it controlled streams of consciousness aliases activated memories of past experiences. And dysfunction successful nan default mode web was floated arsenic a imaginable characteristic of astir each psychiatric and neurological disorder, including depression, schizophrenia, and Alzheimer’s disease.

Since then, a flurry of investigation into nan default mode has analyzable that first understanding. “It’s been very absorbing to spot nan types of different tasks and paradigms that prosecute nan default mode web successful nan past 20 years,” said Lucina Uddin, a neuroscientist astatine nan University of California, Los Angeles.