Accounts of near-death experiences have been circulating since the 1970s when CPR began resuscitating people after cardiac arrest.

A bright light.

A compassionate, peaceful being.

Deceased loved ones waiting with open arms.

All of these accounts allude to the idea that something exists after death. Or at least the brain believes so.

Now, the on this topic reports that these experiences may prove we’re still conscious during the early minutes of death.

“Death has always been defined by when the heart stops beating, because what happens when the heart stops beating is that there’s no blood getting around the body, so almost immediately a person stops breathing and their brain shuts down and becomes nonfunctional,” Dr. Sam Parnia, co-author of a recent study of life after death by a team at the NYU Langone School of Medicine, told Healthline. “This is clinically referred to as cardiac arrest.”

Parnia explains that when a person is resuscitated with CPR, the brain only gets about 15 percent of the blood that normally circulates to it.

“This isn’t enough to reactivate the brain, so the brain by in large remains flat and doesn’t function during CPR,” said Parnia. “As soon as the heart stops, you not only lose consciousness and your brain stem reflexes are all gone, but also the electricity that your brain creates slows down immediately, and within about 2 to 20 seconds it completely flatlines.”

Up until Parnia’s current research, it’s been thought that when a person flatlines, they must be unconscious because no brain waves are detected.

However, he’s challenging this notion.

“We think of death as a finite time,” Parnia said. “But science has come to understand that after a person has died, the cells inside the body start to undergo a process of death themselves, which takes a number of hours after the person is dead.”

Parnia isn’t inferring that after a person is dead that they’re alive, or that after they die, their brain or organs are working.

His point is that cells don’t decompose in an instant. Rather, it takes a few hours before they reach a point in the decomposing process when they’re unsalvageable.

“So the point of our research was this: If we can restart the heart after a person has gone through the first period of death, before the cells have become irreversibly damaged, then we can bring back a whole person without brain damage, or what’s called a disorder of consciousness. Think about the case of Terri Schiavo, who was in a vegetative state,” Parnia explained. “It’s a complicated process, but can be done.”

A look at our conscious — our psyche

In order to study the processes that’ll enable doctors to bring people back to life after cardiac arrest without brain damage, Parnia found it necessary to study the process that occurs in the brain after a person has died.

“Many people have anecdotally reported being able to see and hear what’s going on at the time of their resuscitation. They are going through a period of death, but they come back and describe a detached experience where they are watching doctors work on them from the corner of the room. Or they describe actual conversations that doctors and nurses later verify,” Parnia said.

Part of his research set out to understand this phenomenon of awareness and consciousness during cardiac arrest.

“We wanted to study what happens to the human mind and consciousness. The part that makes us who we are. What the Greeks used to call the psyche. We want to know what happens to that after a person has gone beyond the thresholds of death,” Parnia said.

The study is the largest of its kind. It included 2,000 participants who experienced cardiac arrest.

Some died during the process. But of those who survived, up to 40 percent had a perception of having some form of awareness during the time when they were in a state of cardiac arrest. Yet they weren’t able to specify more details.

“They know they had something, but they couldn’t recall it,” Parnia said.

Ten percent of participants had a deep mystical experience, similar to what might be thought of as a near-death experience.

“They described a bright light coming toward them or deceased relatives welcoming them, or a review of their entire life up to the point when they died flashing before them. Some described seeing a being full of love and compassion,” explained Parnia.

Moreover, 2 percent had full visionary and auditory awareness of all the details of what was happening to them. Of these, one case was validated.

Parnia said he could demonstrate that the person was recalling events that were going on for at least three to five minutes into the period after their heart had stopped.

“There were things that were timed and recorded that the patient was able to independently describe, and when we looked in the charts and asked [medical staff], we verified those exact events occurred,” said Parnia. “What this suggests is that the period of consciousness and awareness of them being able to recall these events was happening not before they died, but during the period when the brain was expected to be flatlined and nonfunctional.”

Parnia said this goes against everything science has discovered so far.

“We went into this expecting there to not be any consciousness awareness, because our scientific models are based upon the fact that you can only have consciousness when your brain is functioning — so that if your brain is going through death and not functioning, then you should not have any of these experiences,” he noted. “[Science also says] these so-called experiences are probably not happening when people are really dead, they are probably happening before or after.”

Still, he said his research proved both wrong.

Not dreams or hallucinations, so what’s happening?

Could what people experience in these moments be dreams or hallucinations?

Parnia said they’re not, because the participants described real events that were verified by others in the room.

The same goes for hallucinations.

“While sick people do have hallucinations, the people we are talking about in this study are describing verifiable events, so by definition they are not hallucinations,” Parnia said.

But what about the mystical experiences people explained? Those can’t be validated.

Parnia chalks this up to the inability to verify another person’s experience when it comes to things like love.

“If you experience profound love for a person or event, there’s no way I could verify if that’s real,” he said. “Thankfully, most of us have not died and come back, so we haven’t experienced it. Some of us are willing to accept it and others aren’t. Scientifically, we have no way of validating someone else’s experience like this. It’s real because they had it.”

Then what about the idea that what’s occurring is experienced by a part of the brain or brain capacity we haven’t discovered yet?

“Yes and no. The idea that we only know 10 percent of our brains may have been the case years ago, but I don’t think that’s correct today. We have a very thorough understanding of how the brain works, and because of science and technology, we have so many ways to peer inside the brain,” Parnia said.

What’s his best explanation then?

Parnia suggests two theories.

The first is that our psyche and consciousness come from an epiphenomenon from brain cell activity. Meaning that because the brain is working, it generates thoughts.

“Kind of like how heat comes off of fire. The heat is not the real thing. The fire is,” Parnia said.

The problem with this idea is that it doesn’t fit our worldview.

No one would be responsible for their actions.

Consider Harvey Weinstein.

“With this concept, he’s not guilty because his brain just generates these things. This is not how we see the world, though. People are responsible for their actions,” said Parnia.

Another model is that the psyche and consciousness that make us who we are is a separate entity of its own. They interact with the brain, but aren’t produced by it.

“Our study supports this idea. You should not have consciousness or activity [during death], but paradoxically we found evidence to the contrary, so we are doing more research,” Parnia said.

Sounds like it all comes down to what philosophers, from ancient to contemporary, have debated for years: What makes us who we are?

“Everything we do in life is determined by consciousness — the psyche — [and] what makes us who we are. But yet we have no plausible biological mechanism to identify how our thoughts come about from brain processes, even though we understand the brain in so much detail,” Parnia said. “My hope is in the future, we’ll be able to measure our thoughts.”