Your Brain Can Taste without Your Tongue[舌头]

Back in ancient times, philosophers like Aristotle[亚里士多德] were already speculating[思索，猜测，推测] about the origins of taste[味觉的起源], and how the tongue[舌头] sensed elemental[基本的，主要的] tastes like sweet[甜], bitter[苦], salty[咸;辛辣] and sour[酸]. "What we discovered just a few years ago is that there are regions of the brain—regions of the cortex[皮质区;皮层]—where particular fields of neurons[神经元] represent these different tastes again, so there's a sweet field, a bitter field, a salty field, etcetera[以及其他; 等等]." Nick Ryba [pron. Reba], a sensory neuroscientist[感知神经科学家] at the National Institutes of Health[国家卫生研究院].

Ryba and his colleagues[同事] found that you can actually taste without a tongue at all[不需要舌头也可以尝味道], simply by stimulating[刺激;激励;使兴奋] the "taste" part of the brain—the insular cortex[岛叶皮质]. They ran the experiment in mice with a special sort of brain implant[移植; 灌输; 植入，插入]—a fiber-optic cable[光纤电缆] that turns neurons[神经元] on with a pulse of laser light[激光脉冲]. And by switching on the "bitter" sensing part of the brain, they were able to make mice pucker up[发脾气，使缩拢], as if they were tasting something bitter—even though absolutely nothing bitter was touching the tongues of the mice.

In another experiment, the researchers fed[喂养] the mice a bitter flavoring[调味品，调味料] on their tongues—but then made it more palatable[可口的; 美味的; 宜人的; 可接受的] by switching on the "sweet" zone of the brain. "What we were doing here was adding the sweetness, but only adding it in the brain, not in what we were giving to the mouse." Think adding sugar to your coffee—but doing it only in your mind. The findings appear in the journal Nature.

Ryba says the study suggests that a lot of our basic judgments about taste—sweet means good, bitter means bad—are actually hard-wired[硬连线的;基本的，固有的，无法改变的] at the level of the brain. As for that virtual-sugar-in-your-coffee idea? "I think it's basically science fiction[科幻小说] to think that this would be something that would be applied to humans." But today’s science fiction might be tomorrow’s artificial sweetener[人造甜味剂].

—Christopher Intagliata

From 60-Second Science