High Stress May Damage Memory
According to a report issued in May 1998, elderly people who have consistently high blood levels of cortisol dont score as well on memory tests as their peers with lower levels of the stress hormone. Whats more, high levels of cortisol are also associated with shrinking of the hippocampus, a region of the brain that plays a key role in learning and memory.
The finding suggest that even cortisol levels in the normal, healthy range can actually accelerate brain aging.
The study results now pride substantial evidence that long-term exposure to adrenal stress hormones may promote hippocampal aging in normal elderly humans, write Nada Porter and Philip Landfield of the University of Kentucky in Lexington in their editorial. Cortisol is a hormone released in response to stress by the adrenal glands, which sit on top of the kidneys.
Over a 5 to 6-year period, Dr. Sonia Lupien and his colleagues measured 24-hour cortisol levels in 51 healthy volunteers, most of whom were in their 70s.
Despite wide variation in cortisol levels, the participants could be divided into three subgroups: those whose cortisol progressively increased over time and was currently high; those whose cortisol progressively increased over time and was currently moderate; and subjects whose cortisol decreased, but was currently moderate.
The researchers tested the volunteers memory on six people in the increasing/high category and five people in the decreasing/moderate group. The groups did not differ on tests of immediate memory, but the increasing/high cortisol group had other memory problems compared with those in the decreasing/moderate group.
The researchers also found that the total volume of the hippocampus in those in the increasing/high group was 14% lower than those in the decreasing/moderate group, although there were no differences in other brain regions.
The results suggest that brain again can be accelerated by levels of adrenal hormones that are not generally regarded as pathological and that variation within this normal range is related to variation in the rate of brain aging, write Porter and Landfield. This further suggests that chronic stress may accelerate the worsening of hippocampus.
1. The part of the brain important for a persons learning and memory is
A) the cortisol.
B) the adrenal glands.
C) the stress hormones.
D) the hippocampus.
2. When the levels of cortisol go higher, the hippocampus in the brain may
A) become larger.
B) become smaller.
C) be missing.
D) be totally damaged.
3. According to the article, when people feel too worried or nervous or when they overwork,
A) the adrenal glands will produce a stress hormone.
B) the kidneys will produce adrenal glands.
C) the hippocampus will produce high level of cortisol in the blood.
D) the cortisol will produce something that makes a poorer memory.
4. When the total volume of the hippocampus becomes smaller, other brain regions
A) become smaller too.
B) Become larger.
C) may remain the same in size.
D) may be damaged.
5. Porter and Landfields research shows that
A) the change in the levels if adrenal hormones has nothing to do with the degree of brain aging.
B) the change in the levels of adrenal hormones has a lot to do with the degree of brain aging.
C) the long-term stress will gradually make the hippocampus worse.
D) None of the above is correct.
答案: DBACB
国内英语资讯:Top CPC leaders reaffirm mission at Partys birthplace
国际英语资讯:U.S. Fed leaves interest rates unchanged amid Fed Chair speculation
国际英语资讯:Greek Migration Minister pleads for more aid to refugees
国内英语资讯:Chinese legislators warn of grave situation in solid waste control
国内英语资讯:China acts to evaluate burden reduction measures for enterprises
2017年12月四级作文范文:加人志愿者的队伍
2017英语四级作文范文:爱玩游戏的大学生
如何为求职面试做准备?
你真的会用“excuse me”吗?
国内英语资讯:China, Russia agree to further cooperation
这些‘不好的’习惯实际上是聪明的迹象
Doesn’t hold a candle?
国际英语资讯:Chinas stable factory activity points to solid economy
国际英语资讯:Spotlight: Abe reelected as Japanese PM amid calls for further probe into scandals
2017英语六级作文范文备考:言论自由
雄安新区首次公开招聘 应聘与招聘人数比为179比1
A Good Book 一本好书
体坛英语资讯:Kenyas Cheruiyot targets improvement after debut marathon win
澳大利亚太平洋难民收容中心最后一批难民拒接撤离
国内英语资讯:Chinese political advisors study spirit of CPC National Congress
什么让你内心很强大?
这照片让人震惊!加勒比海被塑料垃圾“活埋”
泰国吊销被罢免的前总理的护照
国内英语资讯:Chinese, Russian PMs meet in Beijing on ties
国际英语资讯:Spotlight: Repeatedly shooting incidents spark debate again
长相出众好找工作?研究:颜值高的人找这类工作会受歧视
体坛英语资讯:Maradona: Higuain deserves Argentina recall
中国国际论文被引用数排名升至全球第二
国际英语资讯:Kenyas Odinga dismisses repeat election results
为什么你会怕蛇,怕蜘蛛