It truly is one of life’s greatest mysteries isn’t it - what happens when you die? The Cleveland Clinic defines death as the moment when your physical body stops working to survive, your breathing ceasing and your heart stops beating.

While organs such as the liver and the kidneys are known to shut down almost instantaneously, some scientists have contested that brain activity can continue for several minutes or even hours after death.

Back in 2018, researchers from the Stony Brook University of Medicine claimed that the the brain shuts down so ‘slowly’ that it could take hours before activity ceases.

They added that a person ‘may be dead during this time but aware of their surroundings’.

Moreover Dr Sam Parnia, director of critical care and resuscitation research at NYU Langone School of Medicine in New York City, registered brain activity in four people after they were pronounced deceased.

Speaking to Live Science about the study, published in the popular Proceedings of the National Academy of Sciences (PNAS) journal, Dr Parnia explained that the cerebral cortex can survive for around 20 seconds without oxygen.

He stated that while the cerebral cortex remained active, dead people remain conscious but are likely to ‘lose all brain stem reflexes’ during this period.

Once the ‘thinking’ part of the brain ‘flatlines’ after this short time period, it’s unlikely that any brainwaves will be visible on a hospital monitor.

If you want to see this brain activity burst in action then a YouTube user has created a short simulation that’s garnered the attention of the masses.

During the clip, the creator, @hashemalghailiofficialchannel, echoed Dr Parnia’s 20-second cerebral cortex survival window.

“After you die your brain continues to work for more 10 minutes,” the video begins.

“Despite having a functionally dead heart, your brain will continue to work. This is because the cerebral cortex can last without oxygen.

“This part of the brain is responsible for thinking and decision making.”

After watching the fascinating YouTube Short, one user typed: “Energy doesn't die. It just transforms.”

A second remarked: “I knew this before my dad died right infront of me and I said; dad ilysm and don’t worry about me, sis and mom okay? We’re happy that you’re going to a place where there be no more pain, thank you so much for everything and a tear shed from his closed eyes. It was a beautiful moment.”

This is terrifying,” admitted another user. “I can't imagine the sheer panic your brain is going through.”

“I hope it's peaceful and not panicky. This just scared me so much I can't think of anything else. I hope I'm at peace when I die,” commented a fourth.