How much of what you see is a hallucination? - Elizabeth Cox

翻译人员: Riley WANG 校对人员: Lipeng Chen

An elderly woman named Rosalie was sitting in her nursing home

罗萨莉婆婆正坐在养老院的的屋子里，

when her room suddenly burst to life with twirling fabrics.

突然，她的房间充满旋转的图形。

Through the elaborate drapings,

通过精巧的折叠，

she could make out animals,

她能够制作出动物、

children,

儿童、

and costumed characters.

和一些穿着戏服的角色。

Rosalie was alarmed, not by the intrusion,

罗萨莉婆婆感到十分震惊， 并非这些东西突然出现，

but because she knew this entourage was an extremely detailed hallucination.

而是因为她清楚这些都是 细节极其丰富的幻觉。

Her cognitive function was excellent,

她的认知功能一切正常，

and she had not taken any medications that might cause hallucinations.

也并未服用能够引起幻觉的药物。

Strangest of all, had a real-life crowd of circus performers burst into her room,

最奇怪的在于，若在现实中 有这样一群马戏团演员冲进她的房间，

she wouldn’t have been able to see them:

她也无法看到他们，

she was completely blind.

因为她彻底失去了视觉。

Rosalie had developed a condition known as Charles Bonnet Syndrome,

罗萨莉患有邦纳症候群。 (Charles Bonnet Syndrome)

in which patients with either impaired vision or total blindness

患者通常视觉受损或是完全丧失视觉，

suddenly hallucinate whole scenes in vivid color.

眼前却突然出现色彩缤纷的各种幻觉。

These hallucinations appear suddenly,

这些幻觉的出现很突然，

and can last for mere minutes or recur for years.

只会持续几分钟或是在几年内反复发作。

We still don’t fully understand what causes them to come and go,

我们仍然不清楚幻觉出现和消失的原因，

or why certain patients develop them when others don’t.

也尚不明确 为何只有部分患者出现幻觉。

We do know from fMRI studies that these hallucinations

通过功能性磁共振成像，我们发现

这些幻觉会激活 负责视觉的大脑区域，

activate the same brain areas as sight,

areas that are not activated by imagination.

而想象力并不会激发该区域。

Many other hallucinations, including smells,

许多其他的幻觉，包括气味、

sights,

视觉、

and sounds,

和声音，

also involve the same brain areas as real sensory experiences.

都与负责真实感官的大脑区域相同。

Because of this, the cerebral cortex is thought to play a part in hallucinations.

正因为此，大脑皮层被认为与幻觉相关。

This thin layer of grey matter covers the entire cerebrum,

这层薄薄的灰质覆盖整个大脑，

with different areas processing information from each of our senses.

不同的区域负责处理 来自各个感官的信息。

But even in people with completely unimpaired senses,

但即便对于感官完全正常的人来说，

the brain constructs the world we perceive from incomplete information.

大脑也是通过不完整的信息 来构建我们所感知的世界。

For example, our eyes have blind spots

例如，我们的眼睛有盲点，

where the optic nerve blocks part of the retina.

此处的光学神经会阻挡部分视网膜。

When the visual cortex processes light into coherent images,

当视觉中枢处理连续图像的光线时，

it fills in these blind spots with information from the surrounding area.

它会用周边区域的信息来填充盲点。

Occasionally, we might notice a glitch, but most of the time we’re none the wiser.

有时候，我们或许能发现小错， 但绝大多数情况下我们都不够机敏。

When the visual cortex is deprived of input from the eyes, even temporarily,

当视觉中枢不能从眼睛获得信息， 即便只持续短暂的时间，

the brain still tries to create a coherent picture,

大脑仍会试图创造出连续的影像。

but the limits of its abilities become a lot more obvious.

但这种能力的缺陷则更为明显。

The full-blown hallucinations of Charles Bonnet Syndrome are one example.

邦纳症候群中 全面爆发的幻觉就是一个例子。

Because Charles Bonnet Syndrome only occurs in people

由于这种病症只发生在

who had normal vision and then lost their sight,

后天失明的人身上，

not those who were born blind,

先天失明的人并不会患上该疾病，

scientists think the brain uses remembered images

科学家认为大脑使用了记忆中的图像，

to compensate for the lack of new visual input.

来弥补新视觉信息的缺失。

And the same is true for other senses.

对其他感官来说也是同理。

People with hearing loss often hallucinate music or voices,

失聪的人们经常幻听到音乐或说话声，

sometimes as elaborate as the cacophony of an entire marching band.

有时声音能够具体到 像是整个军乐队在演奏。

In addition to sensory deprivation,

除了感官功能缺失、

recreational and therapeutic drugs,

服用消遣及治疗性药物之外，

conditions like epilepsy and narcolepsy,

癫痫和发作性睡病等疾病，

and psychiatric disorders like schizophrenia,

以及精神分裂症等精神失调

are a few of the many known causes of hallucinations,

都是已知的能够导致幻觉的原因。

and we’re still finding new ones.

而我们仍在探索其他原因。

Some of the most notorious hallucinations

一些众人皆知的幻觉

are associated with drugs like LSD and psilocybin.

与LSD和赛洛西宾等致幻剂有很大关系。

Their hallmark effects include the sensation that dry objects are wet

它们的典型影响包括让我们 以为干燥物体是湿润的，

and that surfaces are breathing.

物体表面仿佛在呼吸。

At higher doses, the visual world can appear to melt,

剂量加高之后，眼睛看到的世界 则像是融化一般，

dissolve into swirls,

一切溶解形成漩涡，

or burst into fractal-like patterns.

或是变成分形样式。

Evidence suggests these drugs also act on the cerebral cortex.

证据表明这些药物也会影响大脑皮层。

But while visual impairment typically only causes visual hallucinations,

虽然通常视觉受损只会引发视觉上的幻觉，

and hearing loss auditory ones,

听力缺失只会导致幻听，

substances like LSD cause perceptual disturbances across all the senses.

但LSD这类物质 会干扰所有感官的觉知功能。

That’s likely because they activate receptors in a broad range of brain areas,

这很可能是因为 它激发了大脑大片区域的感受器，

including the cortical regions for all the senses.

包括脑皮质区域的所有感官。

LSD and psilocybin both function like serotonin in the brain,

LSD和赛洛西宾 与大脑中的血清素功能相似，

binding directly to one type of serotonin receptor in particular.

可以与一种特定的 血清素受体直接结合。

While serotonin’s role in the brain is complex and poorly understood,

虽然血清素在大脑中的功能非常复杂， 且我们对其知之甚少，

it likely plays an important part in integrating information

它可能是在整合信息方面发挥重要作用，

from the eyes,

这些信息来自于眼睛、

nose,

鼻子、

ears,

and other sensory organs.

耳朵、

以及其他感受器官。

So one theory is that LSD and psilocybin cause hallucinations

有一种理论认为LSD和赛洛西宾

会通过扰乱感觉统合时的信号 由此导致幻觉。

by disrupting the signaling involved in sensory integration.

Hallucinations associated with schizophrenia

与精神分裂症相关的幻觉

may share a similar mechanism with those caused by LSD and psilocybin.

与由LSD和赛洛西宾造成的幻觉可能 拥有相同的发病机制。

Patients with schizophrenia

患有精神分裂症的病人大脑

often have elevated levels of serotonin in the brain.

通常拥有较高的血清素的水平。

And antipsychotic drugs relieve symptoms of schizophrenia

治疗精神疾病的药物通过 阻断与LSD和赛洛西宾结合的同种血清素受体

by blocking the same serotonin receptors LSD and psilocybin bind to.

来减轻精神分裂症的症状。

And, in some cases,

在某些病例中，

these drugs can even relieve the hallucinations

这些药物甚至能够减轻

of patients with Charles Bonnet Syndrome.

邦纳综合征病人的幻觉。

We’re still a long way from understanding all the different causes

在了解幻觉的全部病因 以及相互联系的机制上，

and interconnected mechanisms of hallucinations.

我们仍有很长的路要走。

But it’s clear that hallucinatory experiences

但现已明确的是

幻觉体验与普通感知的关系 比我们想象的更近。

are much more closely tied to ordinary perception than we once thought.

And by studying hallucinations,

通过研究幻觉，

we stand to learn a great deal

我们能够更多地了解

about how our brains construct the world we see,

我们的大脑如何通过所看、

hear,

所听、

smell,

and touch.

所闻、

所触来构建世界。

As we learn more,

随着我们不断研究，

we’ll likely come to appreciate just how subjective and individual

我们将能够欣赏每个人的感觉世界

each person’s island universe of perception really is.

是多么的主观和独特。