首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
医学
Scientists used to believe adult brains did not grow any new neurons, but it has emerged that new neurons can sprout in the brai
Scientists used to believe adult brains did not grow any new neurons, but it has emerged that new neurons can sprout in the brai
admin
2013-11-14
25
问题
Scientists used to believe adult brains did not grow any new neurons, but it has emerged that new neurons can sprout in the brains of adult rats, birds and even humans. Understanding the process could be important, for finding ways to treat diseases such as Alzheimer’s in which neurons are destroyed.
Most neurons sprouting in adulthood seem to be in the hippocampus, a structure involved in learning and memory. But they rarely survive more than a few weeks. "We thought they were possibly dying because they were deprived of some sort of input," says Elizabeth Gould, a neuroscientist at Princeton. Because of the location, Gould and her colleagues suspect that learning itself might bolster the new neurons’ survival, and that only tasks involving the hippocampus would do the trick.
To test this, they injected adult male rats with a substance that labeled newborn neurons so that they could be tracked. Later, they gave some of the rats standard tasks. One involved using visual and spatial cues, such as posters on a well, to learn to find a platform hidden under murky water. In another, the rats learnt to associate a noise with a tiny shock half a second later. Both these tasks use the hippocampus — if this structure is damaged, rats can’t do them.
Meanwhile, the researchers gave other rats similar tasks that did not require the hippocampus finding a platform that was easily visible in water, for instance. Other members of the control group simply paddled in a tub of water or listened to noises.
The team reported in Nature Neuroscience that the animals given the tasks that activate the hippocampus kept twice as many of their new neurons alive as the others. "Learning opportunities increase the number of neurons," says Gould.
But Fred Gage and his colleagues at the Salk Institute for Biological Studies in La Jolla, California, dispute this. In the same issue of Nature Neuroscience, they reported that similar water maze experiments on mice did not help new neurons survive.
Gould thinks the difference arose because the groups labeled new neurons at different times. She gave the animals tasks two weeks after the neurons were labeled. When the new cells would normally be dying, she thinks the Salk group put their mice to work too early for new neurons to benefit. "By the time the cells were degenerating, the animals were not learning anything." she says.
Which of the following can clearly tell the two groups of rats from each other in the test?
选项
A、The water used.
B、The noises played.
C、The neurons newly born.
D、The hippocampus involved.
答案
D
解析
题干:在测试中,下列哪一个能清晰地将两组老鼠辨别开来?此题为细节定位题,原文中的第四段第一句话可以得出答案。
转载请注明原文地址:https://jikaoti.com/ti/inNDFFFM
本试题收录于:
医学博士外语题库考研分类
0
医学博士外语
考研
相关试题推荐
Severalclassesofbittercitruscompoundhavelookedpromisingasanticanceragentsinlaboratorytests.Anewstudyindicates
Imagineadiseasespreadingacrosstheglobe,killingmostlymiddle-agedpeopleorleavingthemchronicallydisabled.Thenoned
Imagineadiseasespreadingacrosstheglobe,killingmostlymiddle-agedpeopleorleavingthemchronicallydisabled.Thenoned
Imagineadiseasespreadingacrosstheglobe,killingmostlymiddle-agedpeopleorleavingthemchronicallydisabled.Thenoned
Imagineadiseasespreadingacrosstheglobe,killingmostlymiddle-agedpeopleorleavingthemchronicallydisabled.Thenoned
Expertscautionthatnomatterwhichmethodpatientschoose,theymayneedtoweareyeglassesagainoneday—atleastforreadin
Youfeelgenerallydepressedandunabletoconcentrate.Your【C1】______ofdailyactivitymaychange;youfindyourself【C2】______a
Youfeelgenerallydepressedandunabletoconcentrate.Your【C1】______ofdailyactivitymaychange;youfindyourself【C2】______a
Youfeelgenerallydepressedandunabletoconcentrate.Your【C1】______ofdailyactivitymaychange;youfindyourself【C2】______a
PeoplefromaroundtheworldflocktotheUnitedStatesexpectingtofindabetterlife.Buttoscientists’surprise,agrowing
随机试题
某企业2008年息税前利润为200万元,企业资产总额为1000万元,资产负债率为40%,负债资金平均年利率为10%。企业没有优先股和租赁费用。要求:(1)计算企业2008年利息费用;(2)计算企业财务杠杆系数。(注:计算结果保留小数点后两位)
男,56岁,左小腿轻度肿胀,有多条蚓状血管团,其内有硬结,症状逐年加重,如不进行治疗,其最严重的后果是
眶距增宽症常见术后并发症不包括以下哪一项
用成本计算估价法计算国产非标准设备原价时,利润的计算基数中不包括的费用项目是()。【2006年真题】
以课程任务为依据进行分类,课程可分为()。
6,7,18,23,38,()。
设周期为4的函数f(x)处处可导,且,则曲线y=f(x)在(-3,f(-3))处的切线为______.
设随机变量X与Y相互独立,且X服从区间[-1,2]上的均匀分布,y的分布律为Y~,则概率P{X<Y}=
在VisualFoxPro中,程序中不需要用PUBLIC等命令明确声明和建立,可直接使用的内存变量是()。
设有订单表order(订单号,客户号,职员号,签订日期,金额),查询2011年所签订单的信息,并按金额降序排序,正确的SQL命令是( )。
最新回复
(
0
)