When we die, is there a light at the end of the tunnel? Do we know when we’re clinically pronounced dead? How long does it take to actually happen? These are some of the questions that we’ve been asking since the dawn of time. Now, a new study suggests that, yes, we do know when we move on to the Great Beyond.

Recently, researchers at the New York University Langone School of Medicine looked at what happens when the heart no longer beats and we are technically deemed “dead.” Dr. Sam Parnia, director of critical care and resuscitation research, and his group of researchers looked at a series of studies in Europe and the U.S. involving individuals who suffered cardiac arrest, clinically died, and came back to life.

“They’ll describe watching doctors and nurses working; they’ll describe having awareness of full conversations, of visual things that were going on, that would otherwise not be known to them,” Parnia explained to LiveScience (Weisberger, 2017).

When we die, the brain’s cerebral cortex slows down within 2 to 20 seconds. This results in a series of chain reactions that eventually lead to the death of brain cells. However, they may not technically die until hours after the heart has stopped beating (Gallagher, 2017).

“If you manage to restart the heart, which is what CPR attempts to do, you’ll gradually start to get the brain functioning again,” Parnia said. “The longer you’re doing CPR, those brain cell death pathways are still happening — they’re just happening at a slightly slower rate.”

In the end, Parnia and his colleagues concluded that we may still experience some form of consciousness in the “first phase of death.” The stories from those who “came back” from the dead have also lined up with the actual facts in the past.

“What tends to happen is that people who’ve had these very profound experiences may come back positively transformed — they become more altruistic, more engaged with helping others,” Parnia added. “They find a new meaning to life having had an encounter with death.”

But Parnia is not done researching life after death just yet. He and his colleagues are continuing to look into the brain in detail during the period of cardiac arrest, death and revival to better understand how oxygen reaches the brain. Ideally, they want to develop more accurate ways of monitoring the brain from beyond the “threshold of death.”

“In the same way that a group of researchers might be studying the qualitative nature of the human experience of ‘love,’ for instance, we’re trying to understand the exact features that people experience when they go through death, because we understand that this is going to reflect the universal experience we’re all going to have when we die,” he said.