文章大意:本文是一篇说明文。文章主要讨论了一项关于大脑学习的新研究,挑战了以往认为奖励是促进学习的因素的观念。该研究发现,在没有外部奖励的情况下,多巴胺和乙酰胆碱仍然会相互作用,产生一种特定的模式。这种模式持续发生,不受实验中的老鼠是否在跑步或休息的影响。研究结果可能有助于解释大脑如何在自主学习时运作,并为理解抑郁症提供新的视角。
Researchers have long thought that rewards like food or money encourage learning in the brain by causing the release of dopamine (多巴胺), known to enhance the storage of new information. Now, a new study describes how learning still occurs in the absence of rewards.
The study explored the relationship between dopamine and acetylcholine (乙酰胆碱). Past research had shown that they compete with one another. To provide some clarity, the study authors focused on when and under what circumstances dopamine levels are high at the same time as acetylcholine levels are low. They found that this situation occurs frequently, even in the absence of rewards.
“Our findings challenge the current understanding of when and how dopamine and acetylcholine work together,” said study lead author Anne Krok. “Rather than creating unique conditions for learning, rewards take advantage of a mechanism that is already in place and is constantly at work.”
The study team gave dozens of mice access to a wheel on which they could run or rest. On occasion, the researchers offered the animals a drink of water. Then they recorded the mice’s brain activity and measured the amount of dopamine and acetylcholine released at different moments. As expected, the drink treats created the typical patterns of dopamine and acetylcholine release that are prompted by rewards. However, the team also observed that before receiving water treats, dopamine and acetylcholine already followed “rise and fall” cycles approximately twice every second. Krok notes that this pattern continued regardless of whether the mice were running or standing still. “Similar brain waves have been observed in humans during periods of self-examination and rest,” she adds.
“These results may help explain how the brain learns on its own, without the need for external rewards,” said study senior author Nicolas Tritsch.
Tritsch says, “The results of the study may also offer insight into new ways of understanding depression. Lack of motivation is a common symptom of depression, making it challenging to perform basic tasks. It is possible that a disruption (扰乱) in the internal-drive system might be contributing to this issue.”
12. What does the new study find about dopamine and acetylcholine?
A.Their competitive relationship. |
B.The effective cooperation between them. |
C.Their existing working mechanism. |
D.The role they play in information storage. |
13. What do the experiments on mice show?
A.How mouse brains process new information. |
B.The release patterns of dopamine and acetylcholine. |
C.What causes the release of dopamine and acetylcholine. |
D.The difference between mouse brain waves and those of humans. |
14. What might be the cause of depression according to the text?
A.Lack of motivation. |
B.Lack of external rewards. |
C.The inability to deal with tasks. |
D.The disorder of the internal-drive system. |
15. What is the main idea of the text?
A.Learning ability can be improved constantly. |
B.Learning can occur without external rewards. |
C.Rewards encourage learning in the brain. |
D.Dopamine release is the key to learning. |