Arquivo da tag: Mente

Near-death experiences? Results of the world’s largest medical study of the human mind and consciousness at time of death (Science Daily)

Date: October 7, 2014

Source: University of Southampton

Summary: The results of a four-year international study of 2060 cardiac arrest cases across 15 hospitals concludes the following. The themes relating to the experience of death appear far broader than what has been understood so far, or what has been described as so called near-death experiences. In some cases of cardiac arrest, memories of visual awareness compatible with so called out-of-body experiences may correspond with actual events. A higher proportion of people may have vivid death experiences, but do not recall them due to the effects of brain injury or sedative drugs on memory circuits. Widely used yet scientifically imprecise terms such as near-death and out-of-body experiences may not be sufficient to describe the actual experience of death. The recalled experience surrounding death merits a genuine investigation without prejudice.

The results of a four-year international study of 2060 cardiac arrest cases across 15 hospitals are in. Among those who reported a perception of awareness and completed further interviews, 46 per cent experienced a broad range of mental recollections in relation to death that were not compatible with the commonly used term of near death experiences. Credit: © sudok1 / Fotolia

The results of a four-year international study of 2060 cardiac arrest cases across 15 hospitals concludes the following. The themes relating to the experience of death appear far broader than what has been understood so far, or what has been described as so called near-death experiences. In some cases of cardiac arrest, memories of visual awareness compatible with so called out-of-body experiences may correspond with actual events. A higher proportion of people may have vivid death experiences, but do not recall them due to the effects of brain injury or sedative drugs on memory circuits. Widely used yet scientifically imprecise terms such as near-death and out-of-body experiences may not be sufficient to describe the actual experience of death.

Recollections in relation to death, so-called out-of-body experiences (OBEs) or near-death experiences (NDEs), are an often spoken about phenomenon which have frequently been considered hallucinatory or illusory in nature; however, objective studies on these experiences are limited.

In 2008, a large-scale study involving 2060 patients from 15 hospitals in the United Kingdom, United States and Austria was launched. The AWARE (AWAreness during REsuscitation) study, sponsored by the University of Southampton in the UK, examined the broad range of mental experiences in relation to death. Researchers also tested the validity of conscious experiences using objective markers for the first time in a large study to determine whether claims of awareness compatible with out-of-body experiences correspond with real or hallucinatory events.

Results of the study have been published in the journal Resuscitation.

Dr Sam Parnia, Assistant Professor of Critical Care Medicine and Director of Resuscitation Research at The State University of New York at Stony Brook, USA, and the study’s lead author, explained: “Contrary to perception, death is not a specific moment but a potentially reversible process that occurs after any severe illness or accident causes the heart, lungs and brain to cease functioning. If attempts are made to reverse this process, it is referred to as ‘cardiac arrest’; however, if these attempts do not succeed it is called ‘death’. In this study we wanted to go beyond the emotionally charged yet poorly defined term of NDEs to explore objectively what happens when we die.”

Thirty-nine per cent of patients who survived cardiac arrest and were able to undergo structured interviews described a perception of awareness, but interestingly did not have any explicit recall of events.

“This suggests more people may have mental activity initially but then lose their memories after recovery, either due to the effects of brain injury or sedative drugs on memory recall,” explained Dr Parnia, who was an Honorary Research Fellow at the University of Southampton when he started the AWARE study.

Among those who reported a perception of awareness and completed further interviews, 46 per cent experienced a broad range of mental recollections in relation to death that were not compatible with the commonly used term of NDE’s. These included fearful and persecutory experiences. Only 9 per cent had experiences compatible with NDEs and 2 per cent exhibited full awareness compatible with OBE’s with explicit recall of ‘seeing’ and ‘hearing’ events.

One case was validated and timed using auditory stimuli during cardiac arrest. Dr Parnia concluded: “This is significant, since it has often been assumed that experiences in relation to death are likely hallucinations or illusions, occurring either before the heart stops or after the heart has been successfully restarted, but not an experience corresponding with ‘real’ events when the heart isn’t beating. In this case, consciousness and awareness appeared to occur during a three-minute period when there was no heartbeat. This is paradoxical, since the brain typically ceases functioning within 20-30 seconds of the heart stopping and doesn’t resume again until the heart has been restarted. Furthermore, the detailed recollections of visual awareness in this case were consistent with verified events.

“Thus, while it was not possible to absolutely prove the reality or meaning of patients’ experiences and claims of awareness, (due to the very low incidence (2 per cent) of explicit recall of visual awareness or so called OBE’s), it was impossible to disclaim them either and more work is needed in this area. Clearly, the recalled experience surrounding death now merits further genuine investigation without prejudice.”

Further studies are also needed to explore whether awareness (explicit or implicit) may lead to long term adverse psychological outcomes including post-traumatic stress disorder.

Dr Jerry Nolan, Editor-in-Chief of Resuscitation, stated: “The AWARE study researchers are to be congratulated on the completion of a fascinating study that will open the door to more extensive research into what happens when we die.”


Journal Reference:

  1. Parnia S, et al. AWARE—AWAreness during REsuscitation—A prospective study. Resuscitation, 2014 DOI: 10.1016/j.resuscitation.2014.09.004

New ideas change your brain cells, research shows (Science Daily)

Date: 

February 24, 2014

Source: University of British Columbia

Summary: An important molecular change has been discovered that occurs in the brain when we learn and remember. The research shows that learning stimulates our brain cells in a manner that causes a small fatty acid to attach to delta-catenin, a protein in the brain. This biochemical modification is essential in producing the changes in brain cell connectivity associated with learning, the study finds. Findings may provide an explanation for some mental disabilities, the researchers say.

UBC’s Shernaz Bamji and Stefano Brigidi have discovered how brain cells change during learning and memories. Credit: UBC

A new University of British Columbia study identifies an important molecular change that occurs in the brain when we learn and remember.

Published this month in Nature Neuroscience, the research shows that learning stimulates our brain cells in a manner that causes a small fatty acid to attach to delta-catenin, a protein in the brain. This biochemical modification is essential in producing the changes in brain cell connectivity associated with learning, the study finds.

In animal models, the scientists found almost twice the amount of modified delta-catenin in the brain after learning about new environments. While delta-catenin has previously been linked to learning, this study is the first to describe the protein’s role in the molecular mechanism behind memory formation.

“More work is needed, but this discovery gives us a much better understanding of the tools our brains use to learn and remember, and provides insight into how these processes become disrupted in neurological diseases,” says co-author Shernaz Bamji, an associate professor in UBC’s Life Sciences Institute.

It may also provide an explanation for some mental disabilities, the researchers say. People born without the gene have a severe form of mental retardation called Cri-du-chat syndrome, a rare genetic disorder named for the high-pitched cat-like cry of affected infants. Disruption of the delta-catenin gene has also been observed in some patients with schizophrenia.

“Brain activity can change both the structure of this protein, as well as its function,” says Stefano Brigidi, first author of the article and a PhD candidate Bamji’s laboratory. “When we introduced a mutation that blocked the biochemical modification that occurs in healthy subjects, we abolished the structural changes in brain’s cells that are known to be important for memory formation.”

Journal Reference:

  1. G Stefano Brigidi, Yu Sun, Dayne Beccano-Kelly, Kimberley Pitman, Mahsan Mobasser, Stephanie L Borgland, Austen J Milnerwood, Shernaz X Bamji.Palmitoylation of δ-catenin by DHHC5 mediates activity-induced synapse plasticityNature Neuroscience, 2014; DOI: 10.1038/nn.3657

Playing for All Kinds of Possibilities (N.Y.Times)

Buckets of Blickets: Children and Logic: A game developed by researchers at the University of California, Berkeley hopes to show how imaginative play in children may influence development of abstract thought.

By DAVID DOBBS

Published: April 22, 2013

When it comes to play, humans don’t play around.

Alison Gopnik and the Gopnik Lab/University of California, Berkeley. Esther and Benny, both 4, play Blickets with Sophie Bridgers in a lab at the University of California, Berkeley. Children, lacking prior biases, excel in the game, based on associations, but adults flunk it.

Other species play, but none play for as much of their lives as humans do, or as imaginatively, or with as much protection from the family circle. Human children are unique in using play to explore hypothetical situations rather than to rehearse actual challenges they’ll face later. Kittens may pretend to be cats fighting, but they will not pretend to be children; children, by contrast, will readily pretend to be cats or kittens — and then to be Hannah Montana, followed by Spider-Man saving the day.

And in doing so, they develop some of humanity’s most consequential faculties. They learn the art, pleasure and power of hypothesis — of imagining new possibilities. And serious students of play believe that this helps make the species great.

The idea that play contributes to human success goes back at least a century. But in the last 25 years or so, researchers like Elizabeth S. SpelkeBrian Sutton-SmithJaak Panksepp and Alison Gopnik have developed this notion more richly and tied it more closely to both neuroscience and human evolution. They see play as essential not just to individual development, but to humanity’s unusual ability to inhabit, exploit and change the environment.

Dr. Gopnik, author of “The Scientist in the Crib” and “The Philosophical Baby,” and a professor of psychology at the University of California, Berkeley, has been studying the ways that children learn to assess their environment through play. Lately she has focused on the distinction between “exploring” new environments and “exploiting” them. When we’re quite young, we are more willing to explore, she finds; adults are more inclined to exploit.

To exploit, one leans heavily on lessons (and often unconscious rules) learned earlier — so-called prior biases. These biases are useful to adults because they save time and reduce error: By going to the restaurant you know is good, instead of the new place across town, you increase the chance that you’ll enjoy the evening.

Most adults are slow to set such biases aside; young children fling them away like bad fruit.

Dr. Gopnik shows this brilliantly with a game she invented with the psychologist David Sobel (her student, now a professor at Brown). In the game, which has the fetching name Blickets, players try to figure out what it is that makes an otherwise undistinguished clay figure a blicket. In some scenarios you can win even if you’re applying a prior bias. In others you can’t.

Last summer I joined Dr. Gopnik behind a wall of one-way glass to watch her lab manager, Sophie Bridgers, play the game with an extremely alert 4-year-old, Esther.

Seated at a child-size table, Esther leaned forward on her elbows to watch as Ms. Bridgers brought out a small bin of clay shapes and told her that some of them were blickets but most were not.

“You cannot tell which ones are blickets by looking at them. But the ones that are blickets have blicketness inside. And luckily,” Ms. Bridgers went on, holding up a box with a red plastic top, “I have my machine. Blicketness makes my machine turn on and play music.”

It’s a ruse, of course. The box responds not to the clay shapes but to a switch under the table controlled by Ms. Bridgers.

Now came the challenge. The game can be played by either of two rules, called “and” and “or.” The “or” version is easier: When a blicket is placed atop the machine, it will light the machine up whether placed there by itself or with other pieces. It is either a blicket or it isn’t; it doesn’t depend on the presence of any other object.

In the “and” trial, however, a blicket reveals its blicketness only if both it and another blicket are placed on the machine; and it will light up the box even if it and the other blicket are accompanied by a non-blicket. It can be harder than it sounds, and this is the game that Esther played.

First, Ms. Bridgers put each of three clay shapes on the box individually — rectangle, then triangle, then a bridge. None activated the machine. Then she put them on the box in three successive combinations.

1. Rectangle and triangle: No response.

2. Rectangle and bridge: Machine lighted up and played a tune!

3. Triangle and bridge: No response.

Ms. Bridgers then picked up each piece in turn and asked Esther whether it was a blicket. I had been indulging my adult (and journalistic) prior bias for recorded observation by filling several pages with notes and diagrams, and I started flipping frantically through my notebook.

I was still looking when Esther, having given maybe three seconds’ thought to the matter, correctly identified all three. The rectangle? “A blicket,” she said. Triangle? A shake of the head: No. Bridge? “A blicket.” A 4-year-old had instantly discerned a rule that I recognized only after Dr. Gopnik explained it to me.

Esther, along with most other 4- and 5-year-olds tested, bested not just me but most of 88 California undergraduates who took the “and” test. We educated grown-ups failed because our prior biases dictated that we play the game by the more common and efficient “or” rule.

“Or” rules apply far more often in actual life, when a thing’s essence seldom depends on another object’s presence. An arrow’s utility may depend on a bow, but its identity as an arrow does not. Since the “or” rule is more likely correct and simpler to use, I grabbed it and clung.

Esther, however, quickly ditched the “or” rule and hit upon the far less likely “and” rule. Such low-probability hypotheses often fail. But children, like adventurous scientists in a lab, will try these wild ideas anyway, because even if they fail, they often produce interesting results.

Esther and her twin brother, Benny (who played another version of the game), generated low-probability hypotheses as fast as I could breathe. “Maybe if you turn it over and put it on the other end!” “Let’s put all three on!” They were hypothesis machines. Their mother, Wendy Wolfson (who is a science writer), told me they’re like this all the time. “It’s like living with a pair of especially inquisitive otters.”

Alas, Dr. Gopnik said, this trait peaks around 4 or 5. After that, we gradually take less interest in seeing what happens and more in getting it right.

Yet this playlike spirit of speculation and exploration does stay with us, both as individuals and as a species. Studies suggest that free, self-directed play in safe environments enhances resilience, creativity, flexibility, social understanding, emotional and cognitive control, and resistance to stress, depression and anxiety. And we continue to explore as adults, even if not so freely. That’s how we got to the Internet, the moon, and Dr. Gopnik’s lab.

Finally, in the long game of evolution, Dr. Gopnik and some of her fellow scientists hypothesize that humans’ extended period of imaginative play, along with the traits it develops, has helped select for the big brain and rich neural networks that characterize Homo sapiens. This may strike you either as a low-probability or a high-probability hypothesis. But it certainly seems worth playing with.