GPS正在让我们的大脑衰退
你上一次使用纸质地图是在什么时候?你是不是也会把车停在一个陌生街区的停车标志旁，然后呆呆地望着天空，试图追溯你是如何进入这个荒凉的单行道的?
Thanks to the app on that fancy little pocket computer you carry around but call a phone, you no longer have to exercise the part of your brain to use spatial reasoning to work your way out places you're not very familiar with. In fact, a new study published in the journal Nature Communications suggests that satellite navigation, or satnav, effectively "switches off" our hippocampus and prefrontal cortex — the parts of the brain responsible for simulating routes based on prior knowledge, and planning and decision-making, respectively.
多亏了你随身携带的智能手机上的GPS应用程序，你不必再运用你的大脑进行空间推理来帮你在不熟悉的街道找到出路。事实上，发表在《自然通讯》杂志上的一项新研究表明，卫星导航能够有效地“切断”我们的海马体和前额叶皮质(大脑中负责模拟路线的部分)之间的联系。
The research team from University College London (UCL) stuck 24 participants in fMRI machines and had them navigate through a computer simulation of streets in the city of London. The scientists monitored the subjects' brain activity while navigating from memory versus when they simply followed the directions given to them by a satnav device. It turned out that there were major spikes in the activity of both the hippocampus and the prefrontal cortex when the participants encountered giant roundabouts similar to London's Seven Dials or the Magic Roundabout of Swindon, but those parts of the brain didn't fire up when the satnav fed them instructions.
伦敦大学学院(UCL)的研究小组让24名参与者在计算机模拟的伦敦街道中穿行，并使用功能磁共振成像仪监测着参与者的大脑活动。结果表明，当参与者遇到伦敦的地标建筑时，海马体和前额叶皮质的活动都变得十分活跃;但是当卫星导航向他们提供指示时，大脑的这些部分并没有活跃起来。
"If you are having a hard time navigating the mass of streets in a city, you are likely putting high demands on your hippocampus and prefrontal cortex," said lead author Dr. Hugo Spiers of UCL Experimental Psychology, in a press release. "Our results fit with models in which the hippocampus simulates journeys on future possible paths while the prefrontal cortex helps us to plan which ones will get us to our destination. When we have technology telling us which way to go, however, these parts of the brain simply don't respond to the street network. In that sense our brain has switched off its interest in the streets around us."
该研究的首席作者，UCL的实验心理学雨果·斯皮尔斯博士在一次新闻发布会上说：“如果你在一个城市的街道网络里遇到了困难，你可能会对你的海马体和前额叶皮质提出很高的要求。海马体会为我们模拟出可能的路径，而前额叶皮质会帮助我们弄清楚哪些路径可以带我们到达目的地。然而，当我们手头有技术告诉我们该走哪条路时，大脑的这些部分根本不会对街道网络做出反应。也就是说，我们的大脑对周围的街道已经提不起兴趣了”。
Previous research has shown that the gray matter in the memory centers of London cab drivers increases during the 3-to-4-year period of training in which they learn all London's 25,000 streets and countless landmarks, resulting in the hippocampus of these drivers being larger than normal.
之前就有研究表明，伦敦出租车驾驶员的记忆中心灰质在3到4年的训练期里都有所增加。因为在这期间，他们必须记住伦敦25000条街道和无数的地标性建筑，这使得这些驾驶员的海马体大于正常人。
So, what's going to happen to our hippocampi and prefrontal cortices now that we don't rely on them to help us get around anymore? Will those part of our brain atrophy, shriveling to useless raisins and unable to do the work related to memory capabilities we take for granted? The answer is: We don't know yet.
如果我们真的不再依靠海马体和前额叶皮质来四处走动，结果会怎么样呢?它们真的会萎缩成毫无用处的葡萄干，无法再进行与记忆有关的工作吗?目前的答案是：还不清楚。
"Understanding how the environment affects our brain is important," says co-author Dr. Amir-Homayoun Javadi, who ran the brain imaging analysis at UCL, and is now at the University of Kent. "My research group is now exploring how physical and cognitive activity affect brain activity in a positive way. Satnavs clearly have their uses and their limitations."
研究的合著者贾瓦迪博士表示：“了解环境如何影响我们的大脑是很重要的，我的研究小组正在探索身体和认知活动会如何以积极的方式影响大脑活动，并弄清楚它们的用途和局限性”。
