Scientists explain shocking reality of what your brain sees right before you die

Thanatophobia (commonly known as death anxiety) is a genuine fear for many, and without making that worse, death is a tragic reality that will eventually affect us all.

While some become obsessed with the idea that the Grim Reaper is coming for them, there's little factual evidence on what actually happens when we leave this mortal coil.

Movies like Flatliners have toyed with the idea of exploring what happens after death, and while survivors of near-death experiences have sometimes backed up the notion of going into a bright light, others claim we simply cease to exist when our brains stop functioning.

Metro has explained what supposedly happens when we die, focusing on the story of a London-based man called Tom Kearney. Shortly before Christmas in 2009, Kearney was hit by a bus, had his head split open, and his lungs burst.

After being rushed to the hospital, Kearney fell into a coma and had a near-death experience (NDE).

Dr. Charlotte Martial, a neuroscientist with the Coma Science Group and the University of Liege, says that NDEs are characterized as episodes of 'disconnected consciousness' that don't have a connection to our physical environments.

NDEs occur in life-threatening situations like Kearney's, as well as other critical emergencies like heart attacks.

Martial’s research centers on testimonies from NDE patients, with many reporting out-of-body experiences, bright lights, meeting various entities, or experiencing a feeling of harmony.

She backed up the idea that many claim they see their loved ones or see their life flash before their eyes.

The science behind NDEs is a little more complicated, with Martial explaining: "So we notably suggest that hypoxia would be the starting point of the cascade of specific neurochemical mechanisms."

This is where not enough oxygen reaches the cells and certain chemicals are released, which may cause the above testimonies: "We list the neurotransmitter change that may lead to specific features, such as the visual hallucination, or the fact that they feel an intense feeling of peacefulness, or the dissociation that happened at that time."

In terms of the chemicals that are released, she said that while we might associate serotonin with visual hallucinations, neurotransmitters dopamine, noradrenaline, GABA, glutamate, and endorphins are all part of an NDE.

Importantly, this peacefulness could be a biological trigger caused by the body in these extreme situations: "This may arise as a defense mechanism when people face a stressful or life-threatening or painful situation."

Speaking to Metro, Kearney claims he could hear those around him: "[My wife] proceeded to talk to me every day. She brought my friends in, my family visited everyone, and they all talked to me.

"This is extremely important because the coma is a bit like you’re in an underwater submarine and you’re trying to steer yourself by sound.

“I was able to construct a thought world that existed in my coma, which was not deeply unpleasant. I went to lots of places in time. Now I have fully consolidated those memories as dream memories."

Meeting with long-dead relatives, Kearney maintains he was told it wasn't his time, before then stepping through a 'gate'. He was transported to his in-laws' kitchen in New York City, then back to Ireland, and finally through a vine-covered door where he woke up from his coma.

Even though Kearney's experience doesn't sound like a bad one, Martial is fascinated by the more macabre ones: "For me, the most intriguing are the negative experiences.

"Testimonies often describe terrifying scenes, such as encountering monstrous beings or worlds of fire, yet these phenomena remain poorly understood and largely unexplored in the scientific literature."