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
外语
It may be debated whether individual neurons are "tuned" to react to only a single tastant such as salt or sugar-and ther
It may be debated whether individual neurons are "tuned" to react to only a single tastant such as salt or sugar-and ther
admin
2011-01-17
30
问题
It may be debated whether individual neurons are "tuned" to react to only a
single tastant such as salt or sugar-and therefore signal only one taste
quality-or whether the activity in a given neuron contributes to the neural
Line representation of more than one taste. Studies show that both peripheral and
(5) central gustatory neurons typically respond to more than one kind of stimulus,
and although each neuron is attuned most acutely to one tastant, it usually also
generates a reaction to others with dissimilar taste qualities. How then can the
brain represent various taste qualities if each neuron is receptive to many
different-tasting stimuli?
(10) Electrophysiological studies of gustatory sensory neurons, first performed
by Pfaffmann, demonstrated that peripheral neurons are not specifically
responsive to stimuli representing a single taste quality (which might be
symbolized by the pattern of activity across gustatory neurons because the
activity of any one cell was ambiguous) but instead record a spectrum of tastes.
(15) But in the 1970s and 1980s several scientists began to accumulate data indicating
that individual neurons are tuned maximally for one taste, and they interpreted
this as evidence that activity in a particular type of cell represented a given taste
quality—an idea they called the labeled-line hypothesis. According to this idea,
activity in neurons that experience the strongest reaction to sugar would signal
(20) "sweetness," activity in those that are most sensitive to acids would signal
"sourness", and so forth.
Smith later proved that the same cells that previous researchers had
interpreted as labeled lines actually defined the similarities and differences in
the patterns of activity across taste neurons, suggesting that the same neurons
(25) were responsible for taste-quality representation, whether they were viewed as
labeled lines or as critical parts of an across-neuron pattern. These investigators
further established that the neural distinction among stimuli of different
qualities depended on the simultaneous activation of different cell types, much
as with the function of color vision, but unlike auditory perception. These and
(30) other considerations have led us to favor the idea that the patterns of activity
are key to coding taste information.
Scientists now know that things that taste similarly evoke similar patterns
of activity across groups of taste neurons. Furthermore, we can compare these
patterns and use multivariate statistical analysis to plot the similarities in the
(35) patterns elicited by various tastants. Taste researchers have generated such
comparisons for gustatory stimuli from the neural responses of hamsters and
rats and these correspond very closely to similar plots generated in behavioral
experiments, from which we may infer which stimuli taste alike and which taste
different to animals. Such data show that the across-neuron patterns contain
(40) sufficient information for taste discrimination and this may be a reasonable
explanation for neural coding in taste, though researchers continue to debate
whether individual neuron types play a more significant role in taste coding than
they do in color vision. Scientists question whether taste is an analytic sense, in
which each quality is separate, or a synthetic sense like color vision, where
(45) combinations of colors produce a unique quality.
Which of the following statements about the individual gustatory neuron is true, based on information provided by the passage?
选项
A、It creates a neurological signal only when it comes into contact with its primary tastant.
B、Its function is not to identify tastes, but to identify similarities and differences between them.
C、Its primary importance is in distinguishing between the various qualities of a mixed stimulus.
D、It provides roughly equivalent signals when in contact with a major stimulus and a minor one.
E、It plays a fairly minor role in the across-pattern theory, compared to the labeled-line theory.
答案
B
解析
转载请注明原文地址:https://kaotiyun.com/show/xIjO777K
本试题收录于:
GRE VERBAL题库GRE分类
0
GRE VERBAL
GRE
相关试题推荐
Isthereaconnectionbetween______youeatandmaintaininggoodhealth?
JohnSmith,adiligentstudent,neverrefusesto______moreresponsibilitiesthatareassignedtohim.
______isoftenthecasewithanewidea,moreconditionsshouldbeconsidered.
Today,peopleliveinaworld______newtechnologyistakinganincreasingproportionintheirlives.
Linda:Firstly,allowmetointroducemyself.MynameisLinda,managerofthecompany.Tom:______
Oursocietyhaschangedand______init.
Proportionally,morepersonsdiagnosedashavingthebraindisorderschizophreniawereborninthewintermonthsthanatanyoth
A、unrestrainedlysupportiveB、extremelycriticalC、perfectlyneutralD、intellectuallydishonestE、tentativelyreceptiveB
ACCOLADE:
Philosophy,unlikemostothersubjects,doesnottrytoextendourknowledgebydiscoveringnewinformationabouttheworld.Ins
随机试题
对于颅内出血新生儿,首要的护理措施为
急性早幼粒细胞白血病的特异性分子生物学改变是
A.维生素B1缺乏B.维生素A缺乏C.维生素D缺乏D.维生素B5缺乏E.维生素C缺乏夜盲症
如下图所示的匀质梯形薄板ABCE,在A处用细绳悬挂,欲使AB边保持水平,则需在正方形ABCD的中心挖去一个半径为()的圆形薄板。
A企业2009年8月发生如下的经济业务:①销售甲产品,价款40000元,增值税6800元,款项尚未收到,成本为20000元。②计算本川应交城市维护建设税420元,教育费附加180元。③本月结算职工工资5000元,其中生产1人
美国货币监理署(OCC)认为,()是指经营决策错误,或决策执行不当,或对行业变化束手无策,而对商业银行的收益或资本形成现实和长远的影响。
编制培训预算方案前,应当采集与员工培训相关的信息,这些信息不包括()。
设计组织者的目的是为新的学习任务提供观念上的固定点,所以组织者一定呈现在要学习的材料之间。
【2014.山西大同】在能力与知识、技能的关系上,下面说法不正确的是()。
某公司行政部人员手机使用情况如下:①小王拨打过行政部所有人的电话;②小李曾经拨打过小赵的电话,但是小赵不曾拨打过其他人的电话;③不曾接听来自行政部其他人电话的人也就不曾拨打过其他人的电话。由此可以推出:
最新回复
(
0
)