英科學家稱“靈魂出竅”實爲生理反應

Some report feeling as if they are hovering above their own bodies, while others find themselves drawn towards a blinding light. But out-of-body experiences are nothing more than a trick of the mind, scientists claim。

They say that common spooky scenarios, such as floating above a hospital bed or walking towards the light at the end of a tunnel, can be explained by the brain trying to make sense of the process of death。

Scientists from the universities of Edinburgh and Cambridge reviewed studies into changes in the brain that cause certain sensations associated with near-death experiences。

Researcher Caroline Watt said one common vision – that of people seeing a bright light which seems to be drawing them into the afterlife – is probably produced by the death of the cells we use to process the light picked up by our eyes and turn it into pictures。

‘It is simply your brain trying to make sense of the unusual experiences you are having,’ Dr Watt said。

Feelings of being out of the body can also be explained by the brain’s behaviour, the journal Trends in Cognitive Sciences reports。

‘If you put on a virtual reality headset showing an image of yourself three feet in front, you can trick your brain into thinking that is you over there, and get the sense you are outside your body,’ Dr Watt added。

‘The scientific evidence suggests that all aspects of the near-death experience have a biological basis.’

In another example, the hormone noradrenaline, which is released when we suffer from stress and injuries, could be behind the feelings of love and peace many experience when they seem to be approaching death。

However, other scientists say we should not be so quick to dismiss people’s accounts。

Sam Parnia, of the University of Southampton, stressed that being able to trace something back to the brain does not mean it is not real。

Dr Parnia, who is close to completing a three-year study of hospital patients’ recollections of their near-death experiences, said: ‘Every experience, whether near-death or otherwise – such as depression, happiness and love – is mediated by the brain。不少有過瀕死體驗的人曾表示當時感覺意識脫離軀體浮在上空，或被眩目的光芒吸引而去。但科學家表示，這種“靈魂出竅”的感覺只是大腦耍的小花招。

科學家證實，常見的瀕臨死亡時的怪異情景，比如感到漂浮在醫院病牀上，或走向隧道盡頭的亮光，都是大腦試圖釐清死亡過程時的反應。

來自愛丁堡大學和劍橋大學的科學家對死前大腦的變化進行了研究。這些變化導致了人們在臨死前會產生特定的感覺。

研究員卡羅琳•瓦特表示，人們在瀕死時看到“指引其前往來生的”亮光的現象，可能是因爲體內用來處理光線的細胞死亡而產生的影像，我們的雙眼平時利用這些細胞接受光線，並轉化爲圖像。

瓦特說：“這只是你的大腦正試圖弄懂你從未有過的經歷。”

據《認知科學趨勢》期刊報道，靈魂出竅的感覺可以用大腦行爲來解釋。

瓦特博士補充說：“如果你戴上虛擬現實的耳機，讓其在你面前3英尺處呈現出你的影像，你就可以騙你的大腦認爲那就是你自己，從而產生‘靈魂出竅’的錯覺。”

“科學研究證實，所有瀕死感覺都有生理學根據。”

另一項研究表明，瀕死時平和安詳的感覺是受去甲腎上腺素的影響。這一激素通常在人們經歷重壓或受傷時釋放。

但也有科學家認爲，不應該這麼快就否定人們的描述。

南安普敦大學的薩姆•帕尼亞強調指出，將其追溯爲大腦活動並不代表人們的感覺就不真實。

帕尼亞博士說：“不管是不是瀕死，人們的沮喪、快樂、愛意等所有體驗都是受大腦調節的。”他即將完成一項有關病人瀕死感覺回憶的研究，該研究耗時三年。