很少注意到自己眨眼? 原来是大脑将其忽略

Scientists have figured out why we rarely notice our own blinking. Our brains simply miss it, they say.

    The quest for the new discovery began in the 1980s, when researchers found that visual sensitivity starts decreasing just before we blink. But what goes on in the brain remained a mystery.

    In the new study, scientists put fiber-optic lights in the mouths of people. The lights were powerful enough to penetrate the roofs of their mouths and strike their retinas, where light is recorded. They wore goggles to block outside light.

    When the test subjects blinked, the amount of light hitting their retinas didn't change. Activity in their brains was monitored by functional magnetic resonance imaging.

    During blinking, brain activity was suppressed in areas that respond to visual input, the scientists report.

    "Transiently suppressing these brain areas involved in visual awareness during blinks may be a neural mechanism for preventing the brain from becoming aware of the eyelid sweeping down over the pupil during a blink and the world going dark," said Christopher Frith at the University College London.

    The results are detailed in the July 26 issue of the journal Current Biology.

    英国科学家日前揭开了人们眨眼的秘密：为什么我们很少注意到自己在眨眼睛呢？科学家给出的答案是：仅仅是我们的大脑将它忽略了而已。

    据美国“生活科学网”7月25日报道，对这项新发现的探索工作于上个世纪80年代就已经开始了。当时研究人员发现，视觉敏感性会在人们眨眼之前开始变弱，但此时大脑内部又发生了什么？人们对此还不得而知。

    在一项新的研究当中，科学家把光学纤维灯放置在人们的嘴里，而这种灯发出的光线足以透过人们的口腔上颚，到达视网膜。在视网膜内，光线被记录下来。同时，这些人还戴着护目镜，以阻挡来自外界的光线。

    研究人员表示，当参与试验的人们眨眼时，落到他们视网膜上的光线量没有发生变化。此时，他们脑部的活动由功能磁共振成像技术进行监控。科学家发现，在人们眨眼的过程中，他们脑部的活动在一个对视觉输入做出反应的区域内被抑制住了。

    对此，伦敦大学学院的克里斯多佛·弗里斯表示，在眨眼的过程中，瞬间抑制这个和视觉意识有关的脑部区域可能是一种神经机制，这种神经机制可防止大脑意识到眼皮突然盖住瞳孔和世界因此变得漆黑一片。

    报道说，这一研究结果被发表在7月26日出版的《现代生物学》杂志上。