Although the hormone adrenaline is known to regulate
memory storage, it does not pass from the blood into
brain cells. We are faced with an apparent paradox: how
can a hormone that does not act directly on the brain
have such a large effect on brain function?
Recently, we tested the possibility that one of the
hormone’s actions outside the brain might be responsible.
Since one consequence of adrenaline release in an animal
is an increase in blood glucose levels, we examined the
effects of glucose on memory in rats. We found that glucose
injected immediately after training enhances memory tested
the next day. Additional evidence was provided by negative
findings: drugs called adrenergic antagonists, which block
peripheral adrenaline receptors, disrupted adrenaline’s
ability to regulate memory but did not affect memory
enhancements produced by glucose that was not stimulated
by adrenaline. These results are as they should be if
adrenaline affects memory modulation by increasing blood
glucose levels.
4. The author refers to the results of the experiment using
adrenergic antagonists as “negative findings” (line 13)
most likely because the adrenergic antagonists
(A) failed to disrupt adrenaline’s effect on memory
(B) did not affect glucose’s ability to enhance memory
(C) did not block adrenaline’s ability to increase blood glucose levels
(D) only partially affected adrenaline’s ability to enhance memory
(E) disrupted both adrenaline’s and glucose’s effect on memory
答案是：B
首先,我對文章的理解是這樣的
待解釋的現象：hormone adrenaline是怎麼不和大腦直接作用而影響記憶？
讀到這,我就知道文章接下來要說明問號的內容 ： hormone adrenaline -> ? -> 記憶
果然,是因為adrenaline產生葡萄糖 而葡萄糖影響記憶
證據1： 把葡萄糖注入老鼠 記憶up
反向證據2 : 某drug會block adrenaline的接收器 所以無法影響記憶
而且不影響不是由adrenaline產生的葡萄糖
我的問題是 我看不懂證據2的意義在哪？為何他是反向證據
而且證據1已經說明葡萄糖響記憶
那麼證據2的"不是由adrenaline產生的葡萄糖”本來就不會被影響阿
為什麼”不是由adrenaline產生的葡萄糖不被影響” 這句話卻成為反向證據的關鍵
我不知道我是不理解文章意思還是沒有搞懂反向證據的意思
麻煩高手解答
謝謝