Blind-Sight

In my post on A Plausible God, I cited blind-sight as an example of sensing that does not lead to conscious perception. 这一显着的神经综合症说明了我们的现实感与意识之间的紧密联系,,en,Larry Weiscrantz和Alan Cowey在牛津大学发现了​​盲视,,en,失明可能是生理性的,,en,当肉眼无法正常工作时,,en,或者它可以是神经系统的,,en,当眼睛发红但视觉信号处理受损时,,en,如果我们的右侧视觉皮层受损,,en,我们在左边是盲人,,en,在检查一侧有这种神经性失明的患者时,,en,Weiscrantz在病人的盲端照射了一点光,,en,然后Weiscrantz要求病人指出它,,en,病人提出抗议,说他看不到它,也不可能指出它,,en,无论如何,Weiscrantz让他去尝试,,en. Larry Weiscrantz and Alan Cowey discovered blind-sight at Oxford about 25 几年前.

Blindness can be physiological, when the physical eye is not functioning properly. Or it can be neurological, when the eye is fne but the visual signal processing is impaired. 例如, if our right visual cortex is damaged, we are blind on the left side. When examining a patient with such a neurological blindness on one side, Weiscrantz shined a little spot of light on the patient’s blind side. Weiscrantz then asked the patient to point to it. The patient protested that he could not see it and could not possibly point to it. Weiscrantz asked him to try anyway. 然后病人开始准确地指出他无法自觉察觉的光点,,en,经过数百次试验,,en,很明显,患者可以正确指出百分之九十九的试验,,en,尽管他在每次审判中都声称他只是在猜测,,en,患者如何确定不可见物体的位置并准确指出其位置,,en,神经系统的原因是我们都有两条视觉通路,,en,新的视觉通路贯穿视觉皮层,,en,老人,,en,备份通路贯穿我们的大脑干至上丘,,en,我们患者失明的原因是他的视觉皮层受损,,en,并没有从一只眼睛和它的视觉神经中获得信号,,en.

After hundreds of trials, it became obvious that the patient could point correctly in ninety-nine percent of trials, even though he claimed on each trial that he was only guessing. How did the patient determine the location of an invisible object and point to it accurately? The neurological reason is that we all have two visual pathways. The new visual pathway goes through the visual cortex. The old, backup pathway runs through our brain stem to the superior colliculus.

The cause of our patient’s blindness was that his visual cortex was damaged, and it did not get the signals from one eye and its optic nerves. 但是信号走向了上丘的平行路线,,en,使用旧的路径,,en,这种重新布局使他能够在空间中找到物体并准确地引导他的手指向不可见的物体,,en,这种盲视症候群告诉我们,只有新的视觉通路才能产生有意识的体验,,en,而旧的路径是完全可用的,,en,为了生存,,en,它不会导致有意识的视觉体验,,en,一个有趣的神经病症,,en,但盲视远不止于此,,en,这是一个相当混乱的哲学难题,,en,病人可以看到的光点,,en,这是真的吗?,,en,我们知道这是真实的,,en,但是如果我们所有人都是盲视的话,,en,如果我们中的一些人由于盲视而开始形成意识的外表,,en,我们会相信他们吗?,,en, using the old pathway. This rerouting allowed him to locate the object in space and guide his hand accurately to point to the invisible object. What this syndrome of blind-sight shows us is that only the new visual pathway leads to a conscious experience. While the old pathway is perfectly usable (for survival, 例如), it does not lead to a conscious experience of vision.

An interesting neurological condition, 毫无疑问. But blind-sight is more than that. It is a rather confounding philosophical conundrum. The spot of light that the patient could see — was it real? 肯定, we know it was real. But what if all of us were blind-sighted? If some of us started developing a semblance of awareness as a result of our blind-sight, would we believe them, 或称他们为妄想,,en,如果有感官,我们可以不知道,,en,我们如何能够确信这一点,,en,感应,,en,或我们的,,en,妄想,,en,这篇文章是英文版的一个编辑版本,,en,信息来自,,en,BBC广播,,en,由V给出,,en,脑与认知中心主任,,en,CA,,ro,我的书提到了这个系列讲座中生理学大脑异常及其感知表现的几个例子,,en,在我的,,en,审查,,en,我答应发布一个合理的上帝概念,,en,一个似是而非的概念,,en,我的意思是一个不违背已知的科学原理的概念,,en,因此应该与所谓的科学世界观保持一致,,en,这个概念的合理性没有提到它的真实性,,en,但它可能会说这是一个错觉,,en,所有的科学,,en? If there are senses that we can be unaware of, how sure can we be of the “sensed”? Or of our “delusions”?

This post is an edited version of section in 虚幻宇宙. The information comes from The Emerging Mind: Reith Lectures on Neuroscience (BBC Radio, 2003) given by V. Š. Ramachandran, the director of the Center for Brain and Cognition, San Diego, CA, 美国. My book refers to several examples of physiological brain anomalies and their perceptual manifestation from this lecture series.

评论