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.
Key: DBACB
习近平访英成果清单
郑州一奇男子每天吃5斤辣椒
007《金手指》女演员:别再叫我们邦女郎
英国传统美食大盘点
方星海将担任中国证监会副主席
小米想要成为中国的亚马逊?
中英文化产生“化学反应”
2015年将成史上最热年份
克雷格表态不再饰演邦德 卷福会成为继任者?
科学家设计公式助你选紧身袜厚度
中英汽车业合作换挡提速
由《琅琊榜》说起:那些年热门电视剧的英文名儿
欧洲央行暗示或加大量化宽松火力
苹果和富士康携手推进可再生能源
那些年我们学过的毛概 你能答对几道题
科学家的另类艺术:细菌作画
百胜剥离中国业务有什么好处
苹果下架众多应用程序 被指涉及用户隐私
中英联合宣言双语全文
库克首次回应苹果造车报道 汽车业巨变将至
百胜中国业务将分拆上市
暖心经典《小王子》中国行人气爆棚
“回到未来”日:专家预测2045年的生活
习大大点名《唐顿庄园》 英伦古风再次来袭
安吉丽娜·朱莉和布拉德·皮特婚姻告急?
皇家加勒比号游轮两周后正式起航
中资机构首单“绿色债券”伦敦上市
苹果CEO库克表示Apple music已有650万付费用户
卡梅伦:英国访客签证有效期延至两年
赛百味将配尺测量三明治尺寸确保“足斤足两”
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |