Welcome to Science of the ScareEvery month I will dissect a Big Science Question from a horror movie and talk through it in (mostly) easy-to-digest terms.

Science and horror have a wild, entangled history and have left us with loads of questions to ponder. Deep, important questions like: just how many ways could we have a zombie pandemic? Is genetic engineering always a slippery slope to monstrosity? This month’s Big Science Question:

What actually goes on in our brains when we die? 

A group of medical students decides to die (temporarily) and risk brain injury for clout. That’s it: that’s the plot of both Flatliners (1990) and its recent-ish remake Flatliners (2017). I sat next to an actual medical student when I saw the latter in theatres and, hoo boy, it’s worth including it in the discussion of depictions of medically-induced deaths. I don’t usually spend too much energy complaining about the lack of verisimilitude in movies, but something about Flatliners (2017) gets under my skin — Flatliners (1990) is chill, though.

Despite being filmed almost 30 decades apart, the process by which each film’s crew of misguided and overly ambitious medical students flatline doesn’t change much. The 1990 medical students, steered by a cocksure Nelson (Kiefer Sutherland), create an ad hoc lab in the bowels of a leaky renaissance (get it?) museum, complete with a gurney, a janky defibrillator, and a tray of drugs. The 2017 crew, led by Courtney (Elliot Page) get to conduct their experiments in much fancier digs — an unused wing of the hospital where they are studying — and they have access to swanky equipment like an MRI machine.

As an aside, MRIs are dangerous machines (also way too expensive to just be sitting in an abandoned hospital wing) — the magnetic fields that they generate are so strong that they can turn nearby magnetic metal objects into projectiles…and yet the students just leave all sorts of metal lying around (including the laptop, which, depending on the hard drive, might not necessarily get bricked, but any magnetic metal bits inside the computer would probably be ruined). Clearly, this is just the tip of the iceberg of my grievances.

But I digress.



Both groups of Flatliners approach death by cooling the body’s core temperature with a cooling blanket (that also doubles as a heating blanket later), introducing an anaesthetic of some sort, and then stopping the heart with a defibrillator. The 1990 version uses sodium pentathol (also known as sodium thiopental) as its anaesthetic of choice, although they also use nitrous oxide for at least the first flatlining attempt with Nelson (Kiefer Sutherland).

If the drug sounds familiar, it’s because sodium pentathol is sometimes referred to as a truth serum, used as a means to weaken the resolve of people under interrogation. It’s also often used as part of the drug cocktail delivered to people receiving execution by lethal injection. These functions, alongside a far-flung history in psychiatry as a tool for unearthing repressed memories makes this drug seem thematically appropriate to Flatliners — and as a fast-acting anaesthetic and barbiturate, it would have gotten the job done in terms of suppressing neurological, cardiovascular, and respiratory functions.


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The newer film replaces sodium pentathol with propofol — in line with real world medicine where propofol has largely replaced sodium pentathol as anaesthetic of choice. Like its predecessor, propofol has been associated with death — it’s used for medically-assisted death in Canada. Unlike sodium pentathol, propofol is known for amnesiac effects — something that’s never addressed in the movie (in fact, all of our Flatliners experience drastically improved recall).


“[…] here’s an important thing to know: defibrillators cannot jumpstart a stopped heart.”


The idea of the cooling and the anaesthetic is that the heart will be chemically and physically suppressed so that it can’t recover when a defibrillating shock is applied. Your heart beats thanks to specialized heart cells beating in tandem. When signals aren’t synchronized and the heart begins beating with the rhythm of a bag of worms, you have cardiac arrest. Defibrillation works like a sort of reset button — when a shock is administered it briefly stalls the heart in the hopes that when it starts again everything will be back in synch. When flatlining — the heart stays stopped.

Coming back to life is a different effort — one that affords the body every opportunity to power back up. It begins with warming the body back up to a cozier temperature (to prep for death, body temperature was dropped to roughly 86˚F). In both movies, defibrillators are used, sometimes with drugs associated with maybe increasing the chance of return-of-spontaneous circulation (sodium bicarbonate and bretylium in the 1990 version— both out of favour today). But here’s an important thing to know: defibrillators cannot jumpstart a stopped heart.

As I said above, they work like a reset button to correct a bad rhythm; they cannot work like a power button. CPR and administering adrenaline — the first to get oxygenated blood flowing to the brain and body, and the latter to increase arterial pressure and help restore cardiac activity— are much more useful, but these are treated as last-ditch efforts by the students in both movies.


“Brain death. Now it’s real.”

Brain death is a squishy term —it’s generally used to define legal death, but what counts as brain death often changes. Often brain death encompasses the cessation of activity in the whole brain, but sometimes brain death is declared when only cerebral, so-called “higher brain” functions are gone while the brainstem continues to truck along and keep vital organs going. The latter is significant if the legally dead person can act as an organ donor. One thing is agreed upon when it comes to the definition of brain death, however: it’s irreversible.

Rachel (Julia Roberts) got it wrong: the Flatliners are not truly brain dead. They are in cardiac arrest and they are effectively dead in that the electrical activity has dropped to levels too low for an EEG’s sensitivity threshold — giving us that titular flatlining readout. The activity is barely there, but it’s not gone. Just like with the heart’s electrical circuit, if there were zero spark to ignite, there would be no coming back from death.


“I feel like a highly tuned instrument.”

After Nelson comes back from his first flatline, he notes that his senses seem to be amplified. He can perceive far-away sounds that should have been far beyond his range of hearing. The movie is likely playing with the idea that, at death, the brain releases a final cascade of hormones and electrical activity through the body. This same idea is at the crux of the “The Pain Addict” segment of the Black Mirror episode “Black Museum” (2017), a segment that I personally could barely watch because it creeped me out.

The thing is, with cardiac arrest, there is no blood flow to the brain, so how are those hormones circulating? Within 20 seconds of oxygen starvation, the brain doesn’t give a burst of activity. It sort of just peters out from the top down. While it’s a bit of a stretch, the idea is that Nelson might be experiencing a bit of a temporary sensory amplification thanks to a bit of an adrenaline rush the aftermath of coming back to life — not unlike how a fight-or-flight scenario temporarily heightens some sense acuity to help you deal with a threat.



“One thing is agreed upon when it comes to the definition of brain death […] it’s irreversible.”


The 2017 version stretches that idea even further to suggest that a near-death experience somehow instantly rewires your brain to have perfect memory retrieval, with the side effect that post-undeath you’re also extremely horny. Uh. No. Realistically these Flatliners should have felt like garbage from having received chest compressions and defibrillator shocks. Even wilder is the Diffusion Tensor Image that Courtney shows off of her flatlining brain, complete with artful lightning bolts, which is an interesting touch given that DTIs give information about structure (AKA the way in which parts of the brain are connected by neural pathways) and not actual functional brain activity.


She somehow interprets that the mysterious lightning bolts in the prefrontal cortex (an area associated with planning and personality) 15 seconds after death, the ventral tegmental area (a dopaminergic centre that forms part of the brain’s reward system) 40 seconds after death, and then the amygdala (which plays a role in a slew of emotional processes, including fear responses, arousal, and aggression) as proof of her post-death superiorly rewired brain and why flatlining felt good. If anything, this speech scans like someone threw darts at a neuroanatomy textbook and then conveniently ignored that one of the biggest risks to flatlining experiments is permanent cognitive damage.


“Somehow we’ve brought our sins back physically. And they’re pissed.”

According to Flatliners (1990), in death we are faced with our guilt. In coming back to life, our guilt is made manifest until we process it and perform contrition. In Flatliners (2017), past sins are the dominion of some sort of demonic vengeance entity that is keen to torture us for our past mistakes. Both are unusual representations of Near-Death Experiences (NDEs) as compared to how they’re usually depicted.

If you do a quick Google search on the science of NDEs, you’ll likely come across the work of Dr. Sam Parnia (who has been said to prefer the term “actual death experiences), who dedicated years to working with resuscitated patients to articulate the experience of dying. He categorized the experiences that these patients recounted into seven categories, which include fear, seeing animals or plants, seeing a bright light, experiencing violence or persecution, feeling déjà-vu, seeing family, and recalling events post-cardiac arrest.


“Both Flatliners also had ample room to be unsettling medical horror films in the right hands […] but neither version seemed too interested in taking up that thread with any real commitment.”


While it’s interesting that reported Near-Death Experience seem to be easy to place into tidy boxes, Parnia has suggested that the experience likely boils down to “a trick of the mind.” Similarly, Dr. Bruce Greyson has spent years studying NDEs and suggests that there may be something about the decaying brain function during cardiac arrest that allowing for a brain experience similar to what people have reported through sensory deprivation or meditation. If you’re of a spiritual bent, you might interpret that experience as a spiritual one. Science isn’t conclusive about what’s going on in our brains when we die, except that some people seem to perceive something.

Conceptually, Flatliners has the potential to be a thoughtful narrative about regrets that we consciously (or subconsciously) carry and whether we might have to reckon with our sins at the end of our lives. The 1990 version does a much better job of exploring this idea. Both Flatliners also had ample room to be unsettling medical horror films in the right hands, especially when it comes to medicalizing death, but neither version seemed too interested in taking up that thread with any real commitment. Maybe in the next life.


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