Dying brain hints at fleeting conscious experiences

Published

2 years ago

May 2, 2023

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In their last minutes of life, some people’s brains generate a surge of surprisingly organized-looking electrical activity that may reflect consciousness — although scientists aren’t entirely sure.

According to new research, published Monday (May 1) in the journal PNAS (opens in new tab) , this surge can sometimes occur after a person’s breathing stops but before the brain stops functioning. The activity pattern is somewhat similar to what is seen when people are awake or in dreamlike states, leading to speculation that perhaps these electrical surges reflect the otherworldly experiences reported by people who’ve had close brushes with death: A sense of looking at the body from the outside; a tunnel and white light; or a sense of reliving important memories.

However, since all the patients in the new study ultimately died, it’s impossible to know if they had such experiences.

“If you talk about the dying process, there is very little we know,” said Jimo Borjigin (opens in new tab) , a neuroscientist at the University of Michigan Medical School who led the study. It’s rare for patients to have their brains continuously monitored as they die, Borjigin told Live Science. “This is maybe the first study to really show second-by-second how the brain dies.”

Related: Is brain death reversible? Near-death experiences

Some people who are brought back from the brink of death report seeing or hearing unexplained things during resuscitation or when they seem to be unconscious. The reason for these near-death experiences is unknown, and it’s not clear if they’re even specific to death.

International surveys suggest that only about half of what people call “near-death experiences” actually occur in life-threatening situations, said Daniel Kondziella (opens in new tab) , a neurologist at the University of Copenhagen who was not involved in the new research. The other half occur during meditation or in scary situations that don’t endanger one’s health or impact the brain’s metabolism, Kondiziella told Live Science.

“The thing is, from the experience itself you cannot say if someone has had a cardiac arrest or syncope [a brief loss of consciousness] or near-miss traffic accident,” Kondiziella said.

Because the people who survive to report a near-death experience are inherently different from the people who die — their brains don’t permanently lose function, for one thing — it’s hard to determine whether those who actually die also have these subjective experiences.

In 2013, Borjigin and her colleagues measured electrical activity in the brains of rats (opens in new tab) that they euthanized via cardiac arrest. They found that for about 30 seconds after the heart stopped, the brain showed a surge in what are called gamma waves, which are the highest-frequency electrical oscillations in the brain. Gamma waves are correlated with conscious experience, but don’t necessarily prove that someone is conscious; they’re just one of many indicators that someone might be aware and alert.

In 2022, a separate group of doctors happened to be monitoring the brain of an 87-year-old man with an electroencephalogram (EEG), which detects electrical activity on the surface of the brain, when the man unexpectedly died. Similar to Borjigin’s rats, the man’s brain showed a surge in gamma activity in the 30 seconds before and after his heart stopped. ‘Reading’ the dying brain

In their new paper, Borjigin and her team made a deliberate effort to use EEG to capture what the brain looks like during death.

The researchers got permission to monitor dying patients in intensive care whose breathing support had been removed after treatment proved futile. The study included four patients total, all of whom were comatose after cardiac arrest.

In the 30 seconds to two minutes after their ventilators were removed, two of the four patients’ brains showed surges in gamma waves. Interestingly, this gamma activity seemed organized, in that the gamma waves in one portion of the brain were associated with predictable activity patterns in other regions.

The temporoparietal junction, a brain region where the temporal and parietal lobes meet, toward the back of the brain behind the ear, was particularly active with gamma waves. This region is known to be activated when people have out-of-body experiences or dreams, Borjigin said.

The new findings echo what was seen in the 87-year-old patient who unexpectedly died, said Raul Vicente (opens in new tab) , a neuroscientist and data scientist at the University of Tartu who co-authored the 2022 study but was not involved in Borjigin’s work. “It’s very nice to see a confirmation,” he told Live Science.

“The more consistent findings we have, the more evidence it is that this likely is a mechanism happening at the time of death and if we can pinpoint this down to one location, even better,” said Ajmal Zemmar (opens in new tab) , a neurosurgeon at the University of Louisville Health who also co-authored the 2022 study. RELATED STORIES—Dying brains silence themselves in a dark wave of ‘spreading depression’

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Zemmar and Vicente are optimistic that these signals could be signs of conscious experience at the moment of death. But reflecting the debate in the field, Kondziella is more skeptical.

“We know when you die a cardiac death as opposed to a brain death, that takes time,” he said. Minutes pass between the heart stopping and brain cells dying, he said. “It shouldn’t be a big surprise during those minutes, you will see aberrant electrophysiological activity in the brain.”

Some people may experience something like near-death experiences in these moments, Kondziella said, but we may never know for sure. And again, these experiences may not be unique to death — a more likely explanation for near-death experiences that encompasses both life-threatening experiences and non-life-threatening experiences, he said, may be “REM sleep intrusion into wakefulness,” a situation in which the brain blends waking and dreaming states. (REM sleep is marked by dreaming and brain activity patterns that are very similar to waking, including gamma waves and other, lower-frequency waves.)

Borjigin’s team is still collecting end-of-life data, hoping to add to the evidence that the dying brain may generate predictable gamma-wave patterns. Already, other research groups have attempted to use artificial intelligence to identify objects that people saw in their dreams (opens in new tab) based on their brain activity — similar mind-reading may be possible with unconscious and dying patients, Vicente said.

“This opens an opportunity at some point, if we gather enough data, to be able to decode what people in different coma states are thinking,” Vicente said.

World

Mexico and Canada agree to bolster US border security in return for tariff pause

Published

2 hours ago

February 4, 2025

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Mexico and Canada agree to bolster US border security in return for tariff pause

Both Canada and Mexico have agreed to strengthen border security with the United States in return for a 30-day pause in tariffs.

President Trump announced on Sunday he was imposing 25% taxes on goods from his country’s northern and southern neighbours.

Mexico was first to reach a deal with the White House. Its president, Claudia Sheinbaum, said she was sending 10,000 National Guard troops to the US border immediately in return for a tariff delay.

Mr Trump said the Mexican soldiers would be “specifically designated” to stop the flow of the synthetic opioid fentanyl into the US, as well as illegal migrants. Further negotiations will now be carried out, he added.

Ms Sheinbaum said she had a “good conversation” with him lasting at least 30 minutes just hours before the tariffs were due to begin.

She also extracted a concession from Mr Trump – after explaining the “seriousness” of high-powered weapons coming over the border from the US and getting into the hands of criminal groups.

“It gives them firepower,” she said. “We asked that the US also help our country by helping stop this arms trafficking… he agreed.”

Canada made similar moves. Prime Minister Justin Trudeau said almost 10,000 frontline personnel “are and will be working on protecting the border”.

He added on X that his country was appointing a “fentanyl czar”, drugs cartels would be listed as terrorists, and there would be “24/7 eyes on the border”.

There will also be a Canada-US joint strike force to “combat organised crime, fentanyl and money laundering”, Mr Trudeau announced.

Both Trudeau and Trump will view the deal as a win – Trump for seemingly forcing the US’s northern neighbour to act, and Trudeau for heading off sanctions with measures that for the most part (with the exception of the fentanyl czar) had already been announced in December.

Donald Trump said he was “very pleased with this initial outcome” and work will begin see how a “Final Economic Deal” with Canada can be structured.

Analysis: Has it all just been theatre?

First Mexico, now Canada. In another whirlwind day, both of America’s closest neighbours appear to have capitulated to President Trump.
The 25% tariffs on all goods from both countries were due to come into effect at midnight US Eastern time. But after calls between all three leaders, suddenly the tariffs were paused.

So what’s going on? Is this a clear signal of the power Trump wields? His blunt tool of using the threat of tariffs as a negotiating tool has paid off? Bullying tactics work? Well, maybe. At least that’s how Mr Trump wants everyone to think. Dance to my tune, or else.

And it’s absolutely the case that Mexico and Canada were in panic mode this weekend. But surely Donald Trump was panicking a little too when he saw the stock markets on Monday. He claimed this afternoon not to be taking any notice of their sharp falls. But we know he cares deeply about market reactions.

Here’s what’s interesting: the statement from Canadian Prime Minister Justin Trudeau sounded at first glance like it was announcing something new.
“Canada is implementing our $1.3bn border plan… nearly 10,000 frontline personnel are and will be working on protecting the border…”

But it’s not a new announcement. Look at the language – “are and will be”. In other words, “we’re doing this already Mr President, but if you want me to reiterate it to placate you, then I will…” All that Justin Trudeau has done today is reiterate a border plan he announced last December.

Mexico too has been doing an increasing amount in the fight against fentanyl though it could and probably now will do more.

So has it all been theatre this past 24 hours?

A show of brinkmanship from Donald Trump, which could have had a cliff-edge ending, but instead ended with him looking strong (and freaking out much of the developed world in the process) and his closest neighbours forced to reiterate their existing plans.

Regarding China, a 10% tariff – in addition to those already in place – is still set to go ahead, though the White House said Mr Trump is due to talk to President Xi Jinping.

The US president has, however, said 10% could be just the start.

“China hopefully is going to stop sending us fentanyl, and if they’re not, the tariffs are going to go substantially higher,” he said.

China has described fentanyl as America’s problem, and said it would challenge the tariffs at the World Trade Organisation, as well as taking other countermeasures.

But it also left the door open for talks.

What is the UK situation on tariffs?

President Trump hates trade deficits, and does not want to import more goods from another country than are sent there in return, says Sky’s economics and data editor, Ed Conway.

But Britain has bigger trade deficits than the US, Conway adds, and is one of the few countries in the world to import more goods from America than America imports from it.

In addition, because the UK is no longer part of the European Union, any tariffs imposed on Brussels will not affect London.

When asked about the UK, Mr Trump said: “I think that one can be worked out.”

Sir Keir Starmer said it was “early days”.

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