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  3. Scientists sent patterns of electricity coursing across people’s brains, coaxing their brains to see letters that weren’t there.

Scientists sent patterns of electricity coursing across people’s brains, coaxing their brains to see letters that weren’t there.

admin2022-11-16  142
问题     Scientists sent patterns of electricity coursing across people’s brains, coaxing their brains to see letters that weren’t there. The experiment worked in participants who had lost their sight in adulthood, according to the study published in the journal Cell by neuroscientist Michael Beauchamp and neurosurgeon Dr. Daniel Yoshor, both at the Baylor College of Medicine.
    Known as artificial visual devices, the implants were placed on the visual cortex—a brain region that processes incoming information from the eyes—and then stimulated in a pattern to "trace" out shapes that the participants could then "see." The study authors crafted the letters by stimulating the brain with electrical currents, causing it to generate so-called phosphenes— tiny spots of light that people sometimes perceive without any actual light entering their eyes, unlike when light bounces off an object in the room and enters your eyes.
    The team laid an array of electrodes over the region of the brain known as VI, where information from the eyes gets transmitted for early processing. VI works like a map, where different regions of the map correspond to the different zones of our visual field. The authors found that, if they activated one electrode at a time, participants reliably saw a phosphene appear in its predicted zone. But if multiple electrodes came online simultaneously, the individual phosphenes still appeared but did not come together as coherent shapes. So the authors hypothesized that by "sweeping an electrical current across" several electrodes, they could trace patterns onto the surface of the brain and thus generate recognizable shapes.
    "The brain is uniquely tuned to detect changes in our environment, and the organ should track a pattern of phosphenes presented one after the other," the authors said. With this assumption, they generated phosphenes between the locations of two separate electrodes, thus connecting the dots between them, and, surprisingly, the study participants could see the traced shapes and accurately recreate them on a touch screen. When participants in the study began seeing letters form in their minds’ eyes, "I think they were at least as excited as we were, probably more!" Beauchamp and Yoshor said.
    In the future, "these electrodes may be designed to penetrate the cortex so that the electrode tips are closer to the neurons that lie several hundred microns below the cortical surface," they added. "For certain patients, however, surface electrodes may work best, depending on the risks associated with implanting electrodes deeper in their brains," Yoshor said, "There are so many different causes of blindness that some patients may benefit most from deeply implanted electrodes, others from surface electrodes and still others from devices implanted directly into the retinas, which only require eye surgery to implant."
The underlined word "penetrate" (Line 1, Paragraph 5) is closest in meaning to________.
选项 A、go deep into
B、set right
C、see through
D、operate on
答案A
解析 根据题干关键词直接定位到第五段首句。该句中so that the electrode tips are closer to the neurons that lie several hundred microns below the cortical surface(这样电极的端片就可以更加贴近皮层之下数百微米处的神经元)，so that为目的状语从句的连词，因此根据so that后面的内容即可推理出penetrate的含义。由句中closer(更近的)，several hundred microns below(数百微米下)等词，可以推测penetrate的词义应该为“深入；渗透”，选项A go deep into符合句意，故为正确答案。B项set right意为“校正”，本文通篇并未提到脑皮层需要校正的内容，故排除。C项see through意为“识破；看穿”，代入原文句意不通，故排除。D项operate on意为“给……做手术”，语法角度没有问题，但代入原文后与so that之后的内容不能形成逻辑通顺的表达，故排除。
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