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Neuroscientists Figured Out What Unconsciousness Looks Like in the Brain

Just because it's unconscious doesn't mean it's not on.

The human brain is the only reason our species has survived on this planet for so long, but even it has a blind spot. When it’s unconscious — whether because of sleep, anesthesia, or a coma — we’re sitting ducks. That doesn’t mean the brain is completely shut down, though. Studies of the unconscious brain have revealed that it’s still active, but what it’s actually doing is anyone’s guess.

In a trio of papers published on Wednesday, neuroscientists from the University of Michigan Medical School’s Center for Consciousness Science presented their latest stab at understanding the machinations of the unconscious mind. Rather than shutting down completely, one team explained in the Trends in Neurosciences paper, some of the brain’s communication pathways shut down during unconsciousness, which is why processes don’t play out normally even though the different regions of the brain are still active.

“We examined unconsciousness across three different conditions: physiological, pharmacological and pathological,” said University of Michigan Medical School anesthesiology professor George A. Mashour, Ph.D., lead author on the study, in a statement on Wednesday.

“We found that during unconsciousness, disrupted connectivity in the brain and greater modularity are creating an environment that is inhospitable to the kind of efficient information transfer that is required for consciousness.”

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When the brain is unconscious, its different regions become more inwardly connected, creating brain "islands."

This study, together with the related papers in Frontiers in Human Neuroscience and the Journal of Neuroscience, was based on Mashour’s long-standing hypothesis that anesthesia doesn’t shut the brain down but rather cuts off communication between its different regions. Consciousness, as we understand it, is dependent on rapid-fire signals sent from one area to the next. Maintaining it is like ensuring food can be supplied to all the cities in a state. Even if farms are producing goods and cities are ready to receive them, the whole process breaks down if the roads are blocked.

“Instead of seeing a highly connected brain network, anesthesia results in an array of islands with isolated cognition and processing,” said Mashour.

Mashour and his colleagues supported this hypothesis by looking at the brains of people in unconscious states, whether medically induced with anesthesia, sedated into a sleep-like state, or vegetative. In the Journal of Neuroscience article, Mashour and Anthony G. Hudetz, Ph.D., the paper’s senior author and also a professor of anesthesiology, showed that brains in the early stages of sedation take much longer to process information, which is in line with the hypothesis that communication slows down during unconsciousness. They also showed that the individual regions of the brain started to focus their activity inward rather than externally, further supporting the idea that unconsciousness manifests as brain “islands.”

“That tightening might lead to the inability to connect with distant areas,” said Hudetz in a statement.

In the Frontiers in Human Neuroscience paper, the team worked with physicist UnCheol Lee, Ph.D., to quantify the amount of “information integration” in the brain during unconsciousness. The key idea in integrated information theory, a prominent (and very complex) explanation for consciousness, is that “a system is conscious if it possesses a property called Φ, or phi, which is a measure of the system’s “integrated information,” as Scientific American put it in 2015. Lee and colleagues figured that if the brain were isolating its regions into little islands during unconsciousness, then it would be less integrated. Measuring phi as people’s brains slipped into unconsciousness, they found that it did indeed decrease.

Understanding unconsciousness is especially important to anesthesiologists, whose jobs depend on putting people into that state and, crucially, getting them out unharmed. Knowing which highways of the brain shut down and how the reduced flow of signals affects its different regions will someday also help scientists better understand people in comas — and how, or whether, they can be returned to a conscious state.

You Can Save Up to 30 Percent on Your Power Bill With Arcadia Power

Connect to clean, low-cost energy and bring down your power bill for free.

Given the chance, most of us would jump at the opportunity to bring down our power bills. But there’s a prevailing assumption that doing so involves dealing with steep upfront costs before the savings actually come in. Arcadia Power presents a different solution, however, and it’s willing to give new users $20 off their first utility bill for trying out the platform.

Ancient Humans' Tiny Tool Use Is a Big Reason We Are Evolutionarily Unique 

Humans' love of miniaturization allowed for our global spread.

Tools have long been a centerpiece of humans’ ongoing quest to understand our own evolution. Man created tools, and so man has been judged as uniquely, cognitively complex. The problem with this line of thinking, however, is that it’s increasingly obvious that toolmaking and tool use do not make humans as unique as we’d like to think: Many animals, from orangutans to crows, make tools, too.

CIA Psychic Pioneer Explains How Physics Would Have to Change for ESP

"Our answer is a member of the class of things that can explain psychic abilities."

The film The Men Who Stare at Goats had a long laugh at the United States Army’s 20-year-long attempt to use psychic powers to kill animals. Those experiments grew out of the work of physicist Russell Targ, Ph.D., whose studies on psychic “remote viewing” at the Stanford Research Institute in the 1970s drew the attention of the CIA, which later turned it into the goat-felling Stargate Project. That project was abandoned in 1995, and Targ’s work has been panned as pseudoscience ever since. But he stands by what he saw: people who could perceive hidden targets using only their minds.

How a Brutal Murder Had a Profound Ripple Effect on Scientific Thought

A viral story of 38 do-nothing witnesses changed sociology, psychology, and neuroscience.

When 28-year-old Catherine Susan Genovese was killed outside her apartment in Kew Gardens, Queens, 38 people reportedly witnessed the attack but didn’t get involved.

Known to her friends as Kitty, she had only lived at 82-70 Austin Street for a year with her girlfriend, Mary Ann Zielonko, before returning on the night of March 13 from her job managing a bar.

Scientists Think a Gene Causes Birth Control to Fail in Some Women

"We have just always assumed a woman had done something wrong."

Today, there are a variety of contraceptives available that greatly lower the odds of becoming pregnant, but there’s no guarantee attached to any one method.

While ineffectiveness is often blamed on women not taking their birth control properly, new research suggests some women carry a gene that breaks down the hormones commonly found in contraceptives, meaning that they can still become pregnant even if they use hormonal birth control. A study on the gene was published Tuesday in Obstetrics & Gynecology.