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The term 'near-death experience', or NDE, refers to a wide array of experiences reported by some people who have nearly died or who have thought they were going to die. It is any experience in which someone close to death or suffering from some trauma or disease that might lead to death perceives events that seem to be impossible, unusual or supernatural. There is no single shared experience reported by those who have had NDEs. Even the experiences of most interest to parapsychologists--such as the “mystical experience,” the “light at the end of the tunnel” experience, the “life review” experience, and the out-of-body experience (OBE)--rarely occur together in near-death experiences. However, the term NDE is most often used to refer to an OBE occurring while near death.

Here are some of the traits that "typical" NDEs share: ­Int­ense, pure bright light - Sometimes this intense (but not painful) light fills the room. In other cases, the subject sees a light that they feel represents either Heaven or God. Out-of-body experiences (OBE) - The subject feels that he has left his body. He can look down and see it, often describing the sight of doctors working on him. In some cases, the subject's "spirit" then flies out of the room, into ­the sky and sometimes into space. Entering into another realm or dimension - Depending on the subject's religious beliefs and the nature of the experience, he may perceive this realm as Heaven or, in rare cases, as Hell. Spirit beings - During the OBE, the subject encounters "beings of light," or other representations of spiritual entities. He may perceive these as deceased loved ones, angels, saints or God. ­­The tunnel - Many NDE subjects find themselves in a tunnel with a light at its end. They may encounter spirit beings as they pass through the tunnel. Communication with spirits - Before the NDE ends, many subjects report some form of communication with a spirit being. This is often expressed a "strong male voice" telling them that it is not their time and to go back to their body. Some subjects report being told to choose between going into the light or returning to their earthly body. Others feel they have been compelled to return to their body by a voiceless command, possibly coming from God. Life review - This trait is also called "the panoramic life review." The subject sees his entire life in a flashback. These can be very detailed or very brief. The subject may also perceive some form of judgment by nearby spirit entities. Near-death experiences and out-of-body experiences are sometimes grouped together, but there are key differences. An OBE can be a component of an NDE, but some people experience OBEs in circumstances that have nothing to do with death or dying. They may still have spiritual elements or feelings of calm.

OBEs can happen spontaneously, or drugs or meditation can induce them.

What little research there has been in this field indicates that the experiences typical of the NDE may be due to brain states triggered by cardiac arrest, lack of oxygen, increase of carbondioxide and anesthesia. NDEs are the result of physical changes in a stressed or dying brain. Furthermore, many people who have not been near death have had experiences that seem identical to NDEs, for e.g., fighter pilots experiencing rapid acceleration reported similar experiences. [ Being subjected to extreme gravitational forces   that can occur during aerial combat maneuvering, it turns out that under extreme g-forces, fighter pilots lose consciousness and have a near-death experience. Modern fighter aircraft can attain high levels of gravitational forces that put most humans at risk for gravitationally-induced loss of consciousness or G-LOC. The gravitational-stress reduces blood flow to the head and causes pooling of blood in the abdomen and extremities which result in G-LOC. When gravitational stress is applied well above tolerance, there is a short time period during which normal brain function persists, despite loss of adequate blood flow. At the end of this period, consciousness is lost, and the gravitational stress is reduced back to normal conditions. The length of the unconsciousness averaged 12 seconds with a -5 to +5 standard deviation and a range of 2 to 38 seconds. The estimated average length of time blood flow to the central nervous system was altered during the loss and recovery of consciousness was approximately 15 to 20 seconds.This causes  Tunnel vision, floating, automatic movement, autoscopy-the experience in which the individual while believing himself to be awake sees his or her body position outside of his body, out-of-the-body experience, paralysis, not wanting to be disturbed, dreamlets of beautiful places, euphoria, dissociation, pleasure, psychologic state alteration, memories and thoughts inclusion, very memorable experiences, confabulation, strong urge to understand etc.]. It's this reason that fighter pilots wear G-suits and learn techniques to keep their blood flow to their head in order to not pass out. 

Other mimicking experiences may be the result of psychosis (due to severe neurochemical imbalance) or drug usage, such as hashish, LSD, or DMT.

Nevertheless, medical science offers compelling evidence that many aspects of NDEs are physiological and psychological in nature. The causes include an oxygen shortage, imperfect anesthesia, and the body’s neurochemical responses to trauma. Scientists have found that the drugs ketamine and PCP can create sensations in users that are nearly identical to many NDEs. In fact, some users think they are actually dying while on the drug.

The mechanism behind some of these strange experiences is in the way our brains process sensory information. What we see as "reality" around us is only the sum of all the sensory information our brain is receiving at any given moment. When you look at a computer screen, the light from the screen hits your retinas, and information is sent to the appropriate areas of the brain to interpret the light patterns into something meaningful -- in this case, the words you are currently reading. An even more complex system of nerves and muscle fibers allows your brain to know where your body is in relation to the space around it. Close your eyes and raise your right hand until it is level with the top of your head. How do you know where your hand is without looking at it? This sensory system allows you to know where your hand is even when your eyes are closed. Trauma affecting functional areas of the brain, such as the somatosensory and visual cortexes, could cause hallucinations that get interpreted as NDEs. Now imagine that all your senses are malfunctioning. Instead of real sensory input from the world around you, your brain is receiving faulty information, possibly because of drugs, or some form of trauma that is causing your brain to shut down. What you perceive as a real experience is actually your brain trying to interpret this information. Some have theorized that "neural noise," or an overload of information sent to the brain's visual cortex, creates an image of a bright light that gradually grows larger. The brain may interpret this as moving down a dark tunnel.

The body's spatial sense is prone to malfunction during a near-death experience as well. Again, your brain interprets faulty information about where the body is in relation to the space around it. The result is the sensation of leaving the body and flying around the room. Combined with other effects of trauma and oxygen deprivation in the brain (a symptom in many near-death situations), this leads to the overall experience of floating into space while looking down at your own body, and then leaving to float down a tunnel. Using a positron emission tomography (PET) scan, some scientists working in the field showed that the out-of-body experience was related to increased activity in the right temporo-parietal junction, superior temporal, and right precuneal cortices. They suggested that the induced altered spatial self-recognition was mediated by the temporo-parietal junction, which is involved in vestibular-somatosensory integration of body orientation in space. Similarly, some scientists suggested a model to explain out-of-body experiences proposing that “out-of-body experiences are related to a disintegration within personal space (multisensory dysfunction) and disintegration between personal space (vestibular) and extrapersonal (visual) due to interference with the temporo-parietal junction”. In these models, the experience of seeing one’s body in a position that does not coincide with the felt position of one’s body is assumed to be related to temporo-parietal junction dysfunction (2).

Sometimes many out-of-body experiences may be nothing more than anesthesia awareness. Though awareness while under anesthesia is thankfully quite uncommon (about one in every 1,000 people experience it), it is possible that those who believe that they have had a near-death experience are simply constructing false memories through this awareness.
A hallucinatory journey to the bright light and beyond, a full-blown NDE, can occur in 20 or 30 seconds, even though it seems to last much longer. During such a crisis, the very concept of time may seem variable or meaningless. And people think they had these experiences for a long, long time because of distorted sense of time.
A 2010 study of patients who had heart attacks revealed that there may be a correlation between near-death experience of moving in a dark tunnel and the level of carbon dioxide (CO2) in the blood. Out of the 52 cardiac patients studied, 11 reported a near-death experience. The levels of CO2 in the blood of those 11 patients were significantly higher than the patients who did not report having a near-death experience. The feeling among researchers is that the excess CO2 in the bloodstream can have a significant effect on vision, which leads to patients seeing the tunnel and the bright light.
Lack of oxygen to the brain also plays a contributing role. It is well known that oxygen deprivation can lead to hallucinations and may even contribute to the feeling of euphoria that is often reported. Studies have indicated that individuals who reported a near-death experience during cardiac arrest also had lower levels of oxygen. As hallucinations and actual perceptions use the same brain systems, people who had NDEs believe they are very real!

The peaceful, calm sensation felt during NDEs may be a coping mechanism triggered by increased levels of endorphins produced in the brain during trauma. Many people experience a strange sense of detachment and a lack of emotional response during traumatic events (whether or not they were related to a near-death experience). This is the same effect. NDEs that include visits to Heaven or meetings with God could involve a combination of several factors. Faulty sensory input, oxygen deprivation and endorphin-induced euphoria create a surreal, though realistic, experience. When the subject recalls the encounter later, it has passed through the filter of his conscious mind. Bizarre experiences that seem unexplainable become spirit beings, other dimensions and conversations with God.

A spike in epileptic activity in the temporal lobe may be responsible for the visions of God or of heaven that so many see during a near-death experience. A study devised by Orrin Devinsky (3) enabled him and other researchers to “perform clinical and video EEG monitoring in patients as they are having ecstatic-religious seizures, and thus to observe the precise coinciding of their ‘theophanies’ with seizure activity in temporal lobe foci (nearly always these are right-sided).”

The experiences of people whose out-of-body adventures allow them to see and hear events that their unconscious body shouldn't be able to perceive are more difficult to explain. Heightened sensory perception is common in the near-death experience, and a recent study seems to indicate that these feelings of extrasensory perception may be caused by a significant spike in brain activity in the moments just before death. However, it is plausible that unconscious people can still register sensory cues and this coupled with prior knowledge make them incorporate them into their NDE. Whether this is more plausible than the subject's soul floating out of their body is a matter of personal opinion.

Of course, this only scratches the surface of all the possible explanations for an NDE. NDEs seem to offer some hope that death is not necessarily something to be feared, nor is it the end of consciousness. Even science has a difficult time grasping death -- the medical community has struggled with specific definitions for clinical death, organ death and brain death for decades. For every aspect of an NDE, there is at least one scientific explanation for it.

A 13-year Dutch study led by Pim van Lommel and published in Lancet found that 12 percent  of resuscitated patients who had experienced cessation of their heart and/or breathing function reported an NDE. If the cause of the NDE were purely physiological, the researchers reasoned that all of the patients should have had one because of their similar plight. Psychological factors were ruled out by the researchers, as were the medications taken by the patients. However, the researchers believe that neurophysiological processes must play some part in NDE. Similar experiences can be induced through electrical stimulation of the temporal lobe (and hence of the hippocampus) during neurosurgery for epilepsy, with high carbon dioxide levels (hypercarbia), and in decreased cerebral perfusion resulting in local cerebral hypoxia as in rapid acceleration during training of fighter pilots, or as in hyperventilation followed by Valsalva manoeuvre (the action of attempting to exhale with the nostrils and mouth, or the glottis, closed. This increases pressure in the middle ear and the chest, as when bracing to lift heavy objects, and is used as a means of equalizing pressure in the ears). Ketamine-induced experiences resulting from blockage of the NMDA receptor, and the role of endorphin, serotonin, and enkephalin have also been mentioned, as have near-death-like experiences after the use of LSD, psilocarpine, and mescaline. These induced experiences can consist of unconsciousness, out-of-body experiences, and perception of light or flashes of recollection from the past. These recollections, however, consist of fragmented and random memories unlike the panoramic life-review that can occur in NDE. Further, transformational processes with changing life-insight and disappearance of fear of death are rarely reported after induced experiences.

It is possible they constructed false memories ( A false memory is a memory which is a distortion of an actual experience, or a confabulation of an imagined one. Many false memories involve confusing or mixing fragments of memory events, some of which may have happened at different times but which are remembered as occurring together. Many false memories involve an error in source memory. Some involve treating dreams as if they were playbacks of real experiences. Still other false memories are believed to be the result of the prodding, leading, and suggestions of therapists and counselors. It has been shown that not only that it is possible to implant false memories, but that it is relatively easy to do so.)   Stories of the alleged typical NDE have been reported widely in the media. Experiences after the NDE might be used to construct an NDE after-the-fact. It is possible that others had NDEs but don't remember them due either to brain damage, to different abilities in short term memory, or to the timing of their experience vis-à-vis when they regained consciousness.

NDEs can be explained by neurochemistry and are the result of brain states that occur due to a dying, demented, extremely stressed, or drugged brain. Neural noise and retino-cortical mapping explain the common experience of passage down a tunnel from darkness into a bright light. If you started with very little neural noise and it gradually increased, the effect would be of a light at the centre getting larger and larger and hence closer and closer....the tunnel would appear to move as the noise levels increased and the central light got larger and larger....If the whole cortex became so noisy that all the cells were firing fast, the whole area would appear light. Neural activity might explain bright lights, buzzing noises, and hallucinations.

The feelings of extreme peacefulness of the NDE can be credited to the release of endorphins in response to the extreme stress of the situation. The buzzing or ringing sound is attributed to cerebral anoxia and consequent effects upon the connections between brain cells. NDEs can be induced with ketamine, a short-acting hallucinogenic, dissociative anaesthetic. It can reproduce all the main features of the NDE, including travel through a dark tunnel into the light, the feeling that one is dead, communing with some god, hallucinations, out-of-body experiences, strange noises, etc.

Some people who are thought to be dead, but are actually just unconscious, recover and remember things like looking down and seeing their own bodies being worked on by doctors and nurses. They recall conversations being held while they were "dead." Of course, they weren't dead at all, but they feel as if their mind or soul had left their body and was observing it from above. Those who have had such experiences--and they are many--often find them life-altering and defining moments. They are convinced such experiences are proof of life after death by a disembodied consciousness. But are they? It is possible that a person may appear dead to our senses or our scientific equipment but still be perceiving. The visual and auditory perceptions occurring while unconscious-but-perceiving may be produced by a variety of neuronal mechanisms. In fact, we now have evidence that patients who appear brain dead may in fact be capable of conscious thought. In 2006, scientists in the UK and Belgium did an fMRI (functional magnetic resonance imaging) on a woman in a vegetative state and found that parts of her brain showed activity when she was spoken to and asked to think about things like playing tennis. We do not yet know whether NDEs take place just before the crisis, during it, just after it or even during the process of trying to describe it to someone else. If clear consciousness were really possible with a completely flat EEG, this would indeed change our view of the mind/brain relationship, but so far this has not been conclusively demonstrated.


People who believe in NDEs as miracles argue that 'Proof of Heaven' - a book by Dr. Eben Alexander, a neuro-scientist, is a proof from the scientific world. But what the other scientists really think about him and his book is... the brain chemistry of this scientist might have changed during his illness. And his view of the world and reality too have changed with it. There is nothing more to it and a neuro-scientists's experience is no different from an ordinary person's experience if he fails to differentiate between reality and hallucinations and definitely is not a full proof evidence from the scientific world.

A few people even cook up stories to become famous and even admitted later doing that ... like this one: The subject of The Boy Who Came Back From Heaven, published in 2010, the author recently admitted that he made it all up (1)! To the skeptics, these stories and the recent recanting of The Boy Who Came Back From Heaven are just further evidence that NDEs rank right up there with alien abductions, psychic powers, and poltergeists as fodder for charlatans looking to gull the ignorant and suggestible.

Just because their machines don't register anything cannot be taken as proof positive that a person is dead, nor can it be taken as proof positive that the patient isn't aware, on some level, of what is going on around her. Unconscious patients may hear what surgeons and nurses are saying, even if the hospital machines aren't registering any brain activity. Perhaps, they may be communications from doctors, nurses, or others in attendance when the subject is near death, or they may be mixed memories composed after waking up and hearing others talk about what was happening while one was near death, or they may be recollections of subconsciously recorded data overheard while in a groggy state. Therefore, to claim that NDEs provide strong evidence that the soul exists independently of the body, and that there is an afterlife awaiting that soul which just happens to coincide with the beliefs and wishes of the near-death experiment, seems premature and unrealistic.


A hallucination is a fact, not an error; what is erroneous is a judgment based upon it - Bertrand Russell


References:

1. http://www.theatlantic.com/features/archive/2015/03/the-science-of-...

2. http://www.coma.ulg.ac.be/papers/vs/vanhaudenhuyse_NDE2010.pdf
3. https://books.google.co.in/books?id=Zma5jgHKVkYC&pg=PT145&l...

Views: 5061

Replies to This Discussion

Scientists shed light on near-death visions
http://www.dailytelegraph.com.au/technology/sci-tech/scientists-she...
Scientists shed light on near-death visions
THERE may be a scientific explanation for the vivid near-death experiences, such as seeing a shining light, that some people report after surviving a heart attack.

Apparently, the brain keeps on working for up to 30 seconds after blood flow stops, according to a study published in the Proceedings of the National Academy of Sciences.

University of Michigan scientists did their research on nine lab rats that were anesthetised and then subjected to induced cardiac arrest as part of the experiment.

In the first 30 seconds after their hearts were stopped, they all showed a surge of brain activity, observed in electroencephalograms (EEGs) that indicated highly aroused mental states.

"We were surprised by the high levels of activity," said senior author George Mashour, professor of anesthesiology and neurosurgery at the University of Michigan.

"In fact, at near-death, many known electrical signatures of consciousness exceeded levels found in the waking state, suggesting that the brain is capable of well-organised electrical activity during the early stage of clinical death.''

Similar results in terms of brain activity were seen in rats that were asphyxiated, the researchers said.

"This study tells us that reduction of oxygen or both oxygen and glucose during cardiac arrest can stimulate brain activity that is characteristic of conscious processing," said lead author Jimo Borjigin.

"It also provides the first scientific framework for the near-death experiences reported by many cardiac arrest survivors."

About 20 per cent of people who survive cardiac arrest report having had visions during a period known to doctors as clinical death.

Mainstream science has long considered the brain to be inactive during this period.

Ms Borjigin said she hopes her team's latest study "will form the foundation for future human studies investigating mental experiences occurring in the dying brain, including seeing light during cardiac arrest."

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http://esciencenews.com/articles/2013/08/15/visualized.heartbeat.ca...
Visualized heartbeat can trigger 'out-of-body experience'
A visual projection of human heartbeats can be used to generate an "out-of-body experience," according to new research to be published in Psychological Science, a journal of the Association for Psychological Science. The findings could inform new kinds of treatment for people with self-perception disorders, including anorexia. The study, conducted by Jane Aspell of Anglia Ruskin University in the UK and Lukas Heydrich of the Swiss Federal Institute of Technology in Lausanne, is novel in that it shows that information about the internal state of the body -- in this case, the heartbeat -- can be used to change how people experience their own body and self.

Volunteers in the study were fitted with a head mounted display (HMD), which served as "virtual reality goggles." They were filmed in real time by a video camera connected to the HMD, which allowed them to view their own body standing two meters in front of them.

By also recording the volunteers' heartbeat signals using electrodes, the timing of the heartbeat was used to trigger a bright flashing outline which was superimposed on the virtual body shown via the HMD.

After watching the outline flash on and off in sync with the heartbeat for several minutes, the subjects experienced a stronger identification with the virtual body, reporting that it felt more like their own body. They also perceived that they were at a different location in the room than their physical body, reporting feeling closer to their double than they actually were, and they experienced touch at a different location to their physical body.

"This research demonstrates that the experience of one's self can be altered when presented with information about the internal state of one's body, such as a heartbeat," says Aspell.

"This is compatible with the theory that the brain generates our experience of self by merging information about our body from multiple sources, including the eyes, the skin, the ears, and even one's internal organs."

In the future, Aspell hopes the research might help people suffering with self-perception problems, including anorexia and body dysmorphic disorder. She is currently working on a study about "yo-yo dieters" and how their self-perception changes as they gain and lose weight.

"Patients with anorexia, for example, have a disconnection from their own body," Aspell added. "They look in the mirror and think they are larger than they actually are. This may be because their brain does not update its representation of the body after losing weight, and the patient is therefore stuck with a perception of a larger self that is out of date."

Aspell concludes that "this experiment could be adapted to help people 'reconnect' with their current physical appearance. It could help them realize what the 'real me' actually looks like."

In addition to Aspell and Heydrich, co-authors on the study include Guillaume Marillier, Tom Lavanchy, Bruno Herbelin, and Olaf Blanke., all of the Swiss Federal Institute of Technology in Lausanne, Switzerland.

The study was supported by the Swiss National Science Foundation (Grants 33CM30-124089; Sinergia Grant CRSII1-125135: Balancing Self and Body) and the Fondation Bertarelli.
Source: Association for Psychological Science

This group is a treasure trove! Really, I mean it!


There is nothing paranormal about near-death experiences: how neuroscience can explain seeing bright lights, meeting the dead, or being convinced you are one of them
http://www.sciencedirect.com/science/article/pii/S1364661311001550
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http://www.ncbi.nlm.nih.gov/pubmed/25301715
AWARE-AWAreness during REsuscitation-a prospective study.

Abstract
BACKGROUND:

Cardiac arrest (CA) survivors experience cognitive deficits including post-traumatic stress disorder (PTSD). It is unclear whether these are related to cognitive/mental experiences and awareness during CPR. Despite anecdotal reports the broad range of cognitive/mental experiences and awareness associated with CPR has not been systematically studied.
METHODS:

The incidence and validity of awareness together with the range, characteristics and themes relating to memories/cognitive processes during CA was investigated through a 4 year multi-center observational study using a three stage quantitative and qualitative interview system. The feasibility of objectively testing the accuracy of claims of visual and auditory awareness was examined using specific tests. The outcome measures were (1) awareness/memories during CA and (2) objective verification of claims of awareness using specific tests.
RESULTS:

Among 2060 CA events, 140 survivors completed stage 1 interviews, while 101 of 140 patients completed stage 2 interviews. 46% had memories with 7 major cognitive themes: fear; animals/plants; bright light; violence/persecution; deja-vu; family; recalling events post-CA and 9% had NDEs, while 2% described awareness with explicit recall of 'seeing' and 'hearing' actual events related to their resuscitation. One had a verifiable period of conscious awareness during which time cerebral function was not expected.
CONCLUSIONS:

CA survivors commonly experience a broad range of cognitive themes, with 2% exhibiting full awareness. This supports other recent studies that have indicated consciousness may be present despite clinically undetectable consciousness. This together with fearful experiences may contribute to PTSD and other cognitive deficits post CA.
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Rare Medical Conditions and Suggestive Past-Life Memories: A Case Report and Literature Review
http://www.sciencedirect.com/science/article/pii/S1550830713002073
We aim to report the case of a 38-year-old male with suggestive past-life memories during a regression session and to show how these memories were related to unusual medical conditions: (1) isolated obstruction of the right coronary artery in a young patient, (2) omental infarction, and (3) right aortic arch with isolation of the left subclavian artery. These conditions were related to the following suggestive past-life memories: (1) a priest who committed suicide with a crucifix nailed to his chest and (2) a medieval weapon (skull flail) hitting his cervical and left back region. There was an intriguing relation between the patient's suggestive past-life memories and rare medical conditions. In this article, the authors highlight possible explanations, rarity of findings, and similarities/differences from previous cases and potential pitfalls in this area.

Deep Brain Stimulation Triggers Hallucinations
Close your eyes and imagine home. Sharp details—such as the shape of the front doorknob, the height of the windows, or the paint color—assemble in your mind with a richness that seems touchable. A new study has found where this mental projection lives in the brain by inducing hallucinations in an epilepsy patient. A 22-year-old male was receiving deep brain stimulation to isolate where his daily seizures originated. His disorder appeared after he caught West Nile virus at the age of 10 and subsequently suffered from brain inflammation. His episodes were always preceded by intense déjà vu, suggesting a visual component of his disease, but he had no history of hallucinations. Brain scans revealed a shrunken spot near his hippocampus—the brain’s memory center. Studies had shown that this region—known as the parahippocampal place area (PPA)—was involved with recognizing of scenes and places. Doctors reconfirmed this by showing the patient pictures of a house and seeing the PPA light up on brain scans with functional magnetic resonance imaging (images above show brain activity; yellow indicates stronger activation than red). Thin wire electrodes—less than 2 mm thick—placed in the PPA (yellow dots in right panel) recorded similar brain activity after viewing these pictures. To assess if the PPA was ground zero for seizures, the doctors used a routine procedure that involves shooting soft jolts of electricity into the region and seeing if the patient senses an oncoming seizure. Rather than have déjà vu, the patient’s surroundings suddenly changed as he hallucinated places familiar to him. In one instance, the doctors morphed into the Italians from his local pizza place. Zapping a nearby cluster of neurons produced a vision of his subway station. The findings, published on 16 April in The Journal of Neuroscience, confirm that this small corner of the brain is not only responsible for recognizing places, but is also crucial to recalling a mental vision of that place.

http://news.sciencemag.org/brain-behavior/2014/04/scienceshot-deep-...
''Seeing Scenes: Topographic Visual Hallucinations Evoked by Direct Electrical Stimulation of the Parahippocampal Place Area''
In recent years, functional neuroimaging has disclosed a network of cortical areas in the basal temporal lobe that selectively respond to visual scenes, including the parahippocampal place area (PPA). Beyond the observation that lesions involving the PPA cause topographic disorientation, there is little causal evidence linking neural activity in that area to the perception of places. Here, we combined functional magnetic resonance imaging (fMRI) and intracranial EEG (iEEG) recordings to delineate place-selective cortex in a patient implanted with stereo-EEG electrodes for presurgical evaluation of drug-resistant epilepsy. Bipolar direct electrical stimulation of a cortical area in the collateral sulcus and medial fusiform gyrus, which was place-selective according to both fMRI and iEEG, induced a topographic visual hallucination: the patient described seeing indoor and outdoor scenes that included views of the neighborhood he lives in. By contrast, stimulating the more lateral aspect of the basal temporal lobe caused distortion of the patient's perception of faces, as recently reported (Parvizi et al., 2012). Our results support the causal role of the PPA in the perception of visual scenes, demonstrate that electrical stimulation of higher order visual areas can induce complex hallucinations, and also reaffirm direct electrical brain stimulation as a tool to assess the function of the human cerebral cortex.
http://www.jneurosci.org/content/34/16/5399

study on resuscitated patients hints at consciousness after death
The largest medical study ever performed on near-death experiences has led researchers to suggest that consciousness can last up to three minutes after a person’s heart and brain have shut down.
The idea that consciousness can continue on after your heart stops beating and your brain stops functioning is a pretty wild one, and naturally courts a lot of scepticism. But the more scientists study the supposed phenomenon, the more certain trends are reinforced, giving us a glimpse into what actually might occur when we die.

A team of scientists at the University of Southampton in the UK has just finished a four-year study of 2,060 people who experienced cardiac arrests at 15 hospitals across the UK, the US, and Austria. Having conducted interviews with each of the 330 people who survived about their memories of the event, the researchers found that 40 percent of them felt ‘aware’ for the period of time that they were declared clinically dead. The medical staff at the hospitals successfully restarted their hearts so they could live to tell the tale.

According to The National Post, one man participating in the study described the feeling that he was watching his treatment from the corner of the room, while a female participant was able to recount exactly the actions of the nursing staff that resurrected her over a three-minute period. She could even very accurately describe the sound of the machines that surrounded her ‘dead’ body.
“We know the brain can’t function when the heart has stopped beating, but in this case conscious awareness appears to have continued for up to three minutes into the period when the heart wasn’t beating, even though the brain typically shuts down within 20 to 30 seconds after the heart has stopped,” Sam Parnia, the study leader and a former assistant professor of medicine at Southampton University, told The National Post. He’s now based at the State University of New York in the US.

“The man described everything that had happened in the room, but importantly, he heard two bleeps from a machine that makes a noise at three-minute intervals. So we could time how long the experienced lasted for. He seemed very credible and everything that he said had happened to him had actually happened,” said Parnia.

While not all of the people who survived the ordeal recalled some sort of experience in clinical death, perhaps because the medication they were given was messing with their brain function, The National Post reports that certain trends emerged from the 40 percent that did. One in five reported feeling peaceful, and a third said they felt time either speed up or slow down. Some described bright lights, others described feeling detached from their bodies. Some felt scared that they were drowning.

“Estimates have suggested that millions of people have had vivid experiences in relation to death, but the scientific evidence has been ambiguous at best,” Parnia told The National Post. “Many people have assumed that these were hallucinations or illusions, but they do seem to correspond to actual events. These experiences warrant further investigation.”

Of course, any research into what actually goes on after death will always be controversial, due to the enormous difficulties in gathering enough evidence to support much of anything that’s scientifically sound, but studies like this are at least an intriguing starting point.

The study was published in the journal Resuscitation.
http://www.resuscitationjournal.com/article/S0300-9572%2814%2900765...

http://www.sciencealert.com/there-are-seven-types-of-near-death-exp...
There are seven types of near-death experiences, according to research
Fear
Seeing animals or plants
Bright light
Violence and persecution
Deja-vu
Seeing family
Recalling events post-cardiac arrest

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There  is no evidence that souls exist, that Heaven exists, that after-life  exists. Those who want to believe what they want to believe cannot  understand this. And we don't understand death too properly to come to firm  conclusions  about it. Science is trying to first find out what consciousness is.
And what will happen at the time of death? People  say they have expereinced several things and according to science, these are all illusions created by the brain and scientists were able to reproduce them in labs using certain techniques. please read the article I wrote on this here: http://kkartlab.in/group/some-sc...

https://www.quora.com/What-will-happen-at-the-time-of-death

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How Come Some People Believe in the Paranormal?

http://www.scientificamerican.com/article/how-come-some-people-beli...

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What happens to your body after your death?

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