Tag Archives: death

Near-Death Experiment

August 15, 2013 By in Brains, Science Tags: , , , 3 Comments

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If you own a tv, radio, or computer, you’ve probably heard about the recent neuroscience experiment that studied after-death brain activity in rats. Perhaps you’ve seen it under titles like: Near-death experiences are ‘electrical surge in dying brain’ or Near-death experiences exposed: Surge of brain activity after the heart stops may trigger paranormal visions. You may have heard some jargon about brainwaves and frequency coupling or some such. What does it mean? It is time to chuck your rosary, or at least your copy of Proof of Heaven? (The answer to the latter, in case you’re wondering, is yes.)

The article that caused such a stir was penned by researchers at the University of Michigan and published in the scientific journal PNAS. The experiment was simple and so obvious that I immediately wondered why no one had done it before. The scientists implanted six electrodes in the surface of the rat’s brain. They recorded from the electrodes while the rat was awake and then anesthetized. Finally, they injected a solution into the rat’s heart to make it stop beating and recorded in activity in the rat’s brain while it died. None of these steps are unique. Neuroscientists often place electrodes in the brains of living rats and certainly lab rats are anesthetized and sacrificed on a daily basis. The crucial change that these scientists made was recording after the animal’s death.

What happened once its heart stopped?  A lot, probably more than anyone would have expected. In the first 30 seconds, the researchers observed rapid and coordinated neural activity in the rat’s brain. Unlike under anesthesia, when the rat’s brain was quieter than its wakeful norm, the dying brain was as active and, by some measures, more active than it was when fully awake and alive. We’re not talking about zombie rats here – this activity faded and disappeared beyond the 30-second window after cardiac arrest. Still, something dramatic and consistent happened in those dying moments. The brain activity was essentially the same across all nine rats that died from cardiac arrest and eight other rats that the scientists sacrificed using carbon dioxide inhalation. The results were no fluke.

Of course, these findings (and the headlines touting them in the news) beg the question: is this activity the neural basis for near-death experiences? The answer, of course, is we don’t know. We obviously can’t ask the rats what they experienced, if they experienced anything at all. Still, the activity during the 30-second window wasn’t drastically different from the brain’s wakeful activity, at least according to some of their measures. It’s certainly possible, maybe even probable, that the rat experienced something during this time. That fact alone is intriguing. To say more, we’ll need more grants, more studies, and more dead rats.

For the time being, I’m sure people will spin these results according to their pre-existing beliefs. Some will probably say that the brain activity at death is the physiological echo of God coaxing the soul from the body. And who am I say it ain’t so? But there are certainly other explanations. Neural rhythms arise naturally from the wiring of the brain. Neurons form an incredible number of circuits, or wiring loops, that reverberate. Each neuron is a complex little creature in its own right: electrically charged, tiny, tentacled, and bustling with messenger molecules, neurotransmitters, and ions. When neurons are deprived of oxygen and energy, their electrical charges change drastically, which can cause them to fire errant signals at each other. Without input from the outside world, these errant signals may harmonize in ways that reflect the internal wiring of the system. It’s a little like playing a trumpet. When you blow into the trumpet, your breath is a chaotic rush of air, yet it emerges as a clear and orderly tone. An organized system can make order out of chaos. The same might be said of your brain. And if it turns out that this type of coordinated brain activity actually does cause a special experience when you die, consider it an accidental symphony that plays you one last song before you go.

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Photo credit: Paul Stocker on Flickr, used via Creative Commons license

ResearchBlogging.org

Borjigin J, Lee U, Liu T, Pal D, Huff S, Klarr D, Sloboda J, Hernandez J, Wang MM, & Mashour GA (2013). Surge of neurophysiological coherence and connectivity in the dying brain. Proceedings of the National Academy of Sciences of the United States of America PMID: 23940340

Memory: Up in Smoke?

June 14, 2013 By in Life, Minds Tags: , , 5 Comments

002578cd_scan199_0199I recently joined a memory lab at Wayne State University. The timing seems fitting, as I’ve been doing a little memory experiment of my own of late. My father died ten years ago today and I’ve found myself wondering how my memory of him has fared over the decade. Which parts of him do I remember and which have I lost? They say we live on after we die, if nowhere else than in the memories of those we leave behind. Is it true, or does my father die a little each day as my brain cells age and adjust the strengths of their tiny connections?

I do, at least, remember how my father looked. Certain small details stick out in my memory – the wart beside his nose, his dulled gold wedding band beside a broad, flat knuckle, the remarkable definition of his calf muscles (thanks to his marathon bike rides). I can still see how he brushed his hair back from his face and how he crossed his legs – ankle to knee – and mopped up his sweat with a paper towel after a long ride. But are those the memories that matter? Do I remember how it felt to hug him? Do I remember all of the stories from his youth or any particular instance (of the many) when he said that he loved me? Not really. Not well enough to save him from oblivion.

I imagine I’m not the first person to experience the guilt of forgetting.

Unfortunately, memory loss picks up speed with the passage of time and the brain changes associated with old age. We will only ever have more to feel guilty about. But sometimes, on rare and bittersweet occasions, a chance encounter can trigger a memory we didn’t know we had. It is the psychological equivalent to finding coins wedged between the cushions of the couch and it happened to me a couple years back.

I was walking home from work when I smelled something. It was an odor I couldn’t identify, one that didn’t seem familiar, and yet it filled me with a sense of well-being. I stopped walking and inhaled deeply through my nose. What on earth was this compound? I spotted a man walking half a block ahead of me. He was a professor type with long white hair, a briefcase, and a trail of smoke fanning out behind him. The smell had to be coming from him, yet it was nothing like cigarette smoke.

I started walking again and then picked up the pace to get closer to the man. I’m not proud to say it, but I started to follow him, inhaling as I went. When he turned a corner I caught him in profile and saw that he was smoking a pipe. The intriguing smell was that of pipe smoke. For a moment I was confused. I didn’t recall having ever smelled someone smoking a pipe before and I find both cigar and cigarette smoke aversive.

Then I remembered hearing stories about my dad’s pipe. A professor type himself, my father smoked a pipe for many years and only gave up the habit after a triple bypass surgery. I was three years old at the time. Thanks to childhood amnesia, I don’t remember seeing or smelling my father with his pipe. Yet the memory of that smell, and the comfort I once associated it with, have been buried in my brain all these years like lost coins.

In theory, the memory isn’t a positive one. The secondhand smoke my brother and I inhaled early in life may have had something to do with the asthma we developed later in childhood. Still, my reaction to that stranger’s pipe smoke feels positive.  Precious, even. I’d like to think it reflects how I felt in those early years when I sat in my father’s lap or wrapped my fingers around those broad, flat knuckles. Contented and safe. And as a mother, I’d like to think that I’m planting the same warm feelings in my young daughter. Maybe someday after I’m gone an association will unearth them and she can revisit that innocent comfort all over again.

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Even after I solved the mystery of the scent I followed the smoking stranger for a couple more blocks, inhaling and even closing my eyes as I experienced something of my father that I never knew I knew. It was hard to turn back for home. I didn’t want to lose him quite yet. I wasn’t ready. But then again no one ever is.

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Photo credits: Sally Frye Schwarzlose

Remains of the Plague

May 19, 2013 By in Genes, Science Tags: , , , 2 Comments

The history of science is littered with bones. Since antiquity, humans have studied the remains of the dead to understand the living. The practice is as common now as ever; only the methods have changed. In recent years, high-tech analyses of human remains have solved mysteries ranging from our ancestors’ prehistoric mating patterns to the cause of Beethoven’s death. The latest example of this morbid scientific tradition can be found in the e-pages of this month’s PLOS Pathogens. The colorful cast of characters includes European geneticists, a handful of teeth, a 6th century plague, and the US Department of Homeland Security.

Although the word plague is often used as a synonym for disease, plague actually refers to a particular type of illness caused by the bacterium Yersinia pestis. Rampant infection by Y. pestis was responsible for a recent pandemic in the 19th to 20th centuries. Before that it caused the 14th to 17th century pandemic that included the epidemic known as the Black Death.

Yet the pestilence of pestis may have swept across human populations long before the Black Death. According to historical records, a terrible pandemic killed people from Asia to Africa to Europe between the 6th and 8th centuries. It struck the Roman Empire under the watch of Emperor Justinian I, who contracted the disease himself but survived. The pandemic now bears his name: the Justinianic Plague. But was Justinian’s malady really a plague or has history pinned the blame on the wrong bacterium? A group of researchers in Munich decided to find out.

How?

By digging up ancient graves, of course. And helping themselves to some teeth.

The ancient graves were in an Early Medieval cemetery called Aschheim in the German state of Bavaria. The site was a strange choice; the authors reveal in their paper that the historical record shows no evidence that the Justinianic Plague reached Bavaria. However, the site was conveniently located within driving distance of most of the study’s authors. (It’s always easiest to do your gravedigging closer to home.) The authors did have solid evidence that the graves were from the 6th century and that each grave contained two or more bodies (a common burial practice during deadly epidemics). In total, the group dug up 12 graves and collected teeth from 19 bodies.

The scientists took the teeth back to their labs and tested them for a stretch of DNA unique to Y. pestis. Their logic: if the individuals died from infection by Y. pestis, their remains should contain ample DNA from the bacteria. Of course, some of this DNA would have deteriorated over the course of 1.5 millennia. The scientists would have to make do with what they found. They used three different methods to amplify and detect the bacterial DNA, however they only found a reliably large amount of it in the teeth of one individual, a body they affectionately nicknamed A120. They genotyped the Y. pestis DNA found in A120 to see how the bacterial strain compared with other versions of the bacterium (including those that caused the Black Death and the 19th-20th century plague pandemic.) The analysis showed that the Justinianic strain was an evolutionary precursor to the strain that caused the Black Death. Like the strains that sparked the second and third pandemics, this strain bore the genetic hallmarks of Y. pestis from Asia, suggesting that all three plague pandemics spread from the East.

The authors write that they have solved their historical mystery.

“These findings confirm that Y. pestis was the causative agent of the Justinianic Plague and should end the controversy over the etiological agent of the first plague pandemic.”

Ordinarily, the discussion sections of scientific papers are littered with qualifiers and terms like might be and suggestive. Not so here, even though the authors’ conclusion explains a phenomenon that killed many millions of people worldwide based on data from the decomposing remains of a single person who lived in a region that historians haven’t connected with the pandemic. In most branches of science, sweeping conclusions can only be made based on large and meticulously selected samples. In genetics, such rules can be swept aside. It is its own kind of magic. If you know how to read the code of life, you can peer into the distant past and divine real answers based on a handful of ancient teeth.

As it turns out, the study’s result is more than a cool addition to our knowledge of the Early Middle Ages. Plague would make a terrible weapon in the hands of a modern bioterrorist. That’s why the US Department of Homeland Security is listed as one of the funding sources for this study. So the next time you hear about your tax dollars hard at work, think of Bavarian graves, ancient teeth, and poor old A120.

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Photo credit: Dallas Krentzel

ResearchBlogging.org

Harbeck M, Seifert L, Hansch S, Wagner DM, Birdsell D, Parise KL, Wiechmann I, Grupe G, Thomas A, Keim P, Zoller L, Bramanti B, Riehm JM, Scholz HC (2013). Yersinia Pestis DNA from Skeletal Remains from the 6th Century Reveals Insights Into Justiniac Plague PLOS Pathogens DOI: 10.1371/journal.ppat.1003349

Grandparents’ Last Gift

July 8, 2009 By in Life Tags: , 1 Comment

My fiance’s grandmother passed away today. We will miss her very much. Her passing reminded me of my own grandparents, all of whom died a long time ago. It’s interesting and maybe in its own way poetic that one of the gifts our grandparents give us is our first experience with death. At least for most of us, our grandparents are the first people we truly knew and loved who died.

One of my grandmothers died before I was born, and one grandfather died when I was two, before I can remember. My other grandfather died when I was twelve. My father and I drove all day to reach his nursing home downstate, arriving in time to see the nurses wheel a body bag out of his room. Seeing his face in the casket was my first experience with death. Kissing his cheek at the service was the first time I touched a body devoid of life. I’ve done it more than once since then.

My last grandmother died when I was twenty-one. She died in home hospice care, slipping into a coma and passing away over the course of two days. Her breath and pulse were so faint that we couldn’t tell exactly when they stopped. The hospice nurse told us to watch her fingernails. When they turned blue, she was almost or already gone. I held her hand and watched them blue and when she was gone, I wasn’t as scared of death as I’d been before.

Unlike cultures elsewhere, and certainly, societies of the past, ours is stunningly sheltered from the realities of death. We don’t prepare the bodies of our loved ones for burial or witness their cremation. Their remains disappear and reappear as ashes or clean, well-dressed bodies in silk-lined caskets. Death isn’t something we’re comfortable talking about, even though it’s the one inevitability in our lives. Maybe it’s because the American culture is one of optimism, the make-lemonade-from-lemons mentality. But grandparents give us the gift of a quiet truth: that everything eventually ends, that our parents and spouses and our selves will pass, and that the world will continue without us.

Rest in peace, Shanti Bansal. We will keep you in our hearts and our memories.

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