The decrease in responsiveness that follows continuous stimulation
(adaptation) is common to all sensory systems, including olfaction. With
continued exposure to chronically present ambient odors, individuals’
perception of odor intensity is greatly reduced. Moreover, these perceptual
changes can be profound and durable. It is commonly reported that following
extended absences from the odorous environment, reexposure may still fail to
elicit perception at the original intensity.
Most research on olfactory adaptation examines relatively transient changes
in stimulus detection or perceived intensity—rarely exceeding several hours
and often less—but because olfactory adaptation can be produced with
relatively short exposures, these durations are sufficient for investigating
many parameters of the phenomenon. However, exposures to odors in natural
environments often occur over far longer periods, and the resulting
adaptations may differ qualitatively from short-term olfactory adaptation.
For example, studies show that even brief periods of odorant stimulation
produce transient reductions in receptors in the olfactory epithelium, a
process termed “receptor fatigue.” Prolonged odor stimulation, however,
could produce more long-lasting reductions in response, possibly involving
structures higher in the central nervous system pathway.
The author of the passage discusses“receptor fatigue” primarily in order to
(A) explain the physiological process through which long-lasting reductions
in response are thought to be produced
(B) provide an example of a process that subjects would probably not
experience during a prolonged period of odorant stimulation
(C) help illustrate how the information gathered from most olfactory research
may not be sufficient to describe the effects of extended exposures to
odors
(D) show how studies of short-term olfactory adaptation have only accounted
for the reductions in response that follow relatively brief absences from an
odorous environment
(E) qualify a statement about the severity and duration of the perceptual
changes caused by exposure to chronically present ambient odors
为什么答案是C不是E呢? 短暂暴露在嗅觉刺激的情况下会让嗅觉上皮层的receptor
有短暂的reduction 这和E不应该最符合吗