60秒科学:Freeing the Mind to Forget

Freeing the Mind to Forget
Young brains can forget painful memories, but old ones tend not to. An animal study in the journal Science finds that it may be possible to restore the old brain to its younger, more pliable¹ state. Karen Hopkin reports

Some things are hard to remember. Others are hard to forget—especially things that are traumatic. But kids, it turns out, are better than adults at forgetting the bad stuff. Now scientists think they know why. According to an animal study in the September 4th issue of the journal Science, the brains of adults erect² physical barriers that keep painful memories intact.

As adults, events that emotionally disturb us tend to get seared into our brains. And those memories can resurface, causing anxiety, fear and even post-traumatic stress disorder³. But young brains are much more resilient—and can even erase⁴ unpleasant memories.

To get a better handle on this youthful forgetting, scientists studied the brains of young and old rats. They found that in adult brains, a physical net forms around certain cells in the amygdala, a structure associated with emotional memories. Adults that had been trained to associate a mild foot shock with a specific sound would flinch⁵ when they just heard the sound. But using a drug to dissolve this barrier restored the older rats’ ability to extinguish fearful memories. So rats that got the net-busting treatment stayed calm when they heard the sound.

One of the few instances where a net loss is a real gain.

—Karen Hopkin

1 pliable   

adj.易受影响的；易弯的；柔顺的，易驾驭的

参考例句：

• Willow twigs are pliable.柳条很软。
• The finely twined baskets are made with young,pliable spruce roots.这些编织精美的篮子是用柔韧的云杉嫩树根编成的。

2 erect   

n./v.树立，建立，使竖立；adj.直立的，垂直的

参考例句：

• She held her head erect and her back straight.她昂着头，把背挺得笔直。
• Soldiers are trained to stand erect.士兵们训练站得笔直。

3 disorder   

n.紊乱，混乱；骚动，骚乱；疾病，失调

参考例句：

• When returning back,he discovered the room to be in disorder.回家后，他发现屋子里乱七八糟。
• It contained a vast number of letters in great disorder.里面七零八落地装着许多信件。

4 erase   

v.擦掉；消除某事物的痕迹

参考例句：

• He tried to erase the idea from his mind.他试图从头脑中抹掉这个想法。
• Please erase my name from the list.请把我的名字从名单上擦去。

5 flinch   

v.畏缩，退缩

参考例句：

• She won't flinch from speaking her mind.她不会讳言自己的想法。
• We will never flinch from difficulties.我们面对困难决不退缩。