SLEEP:
When most people think about taking a nap, they typically envision being down for the count for at least an hour or two. A German stuWhen most people think about taking a nap, they typically envision being down for the count for at least an hour or two. A German study, however, has shown that if you really want to refresh your brain, a six-minute catnap will do it. Not only will you feel better afterward, but your ability to learn and remember will have improved as well.
As described in a recent article in the Journal of Sleep Research, students at the University of Dusseldorf participated in experiments in which they had to memorize a list of words and then either take a nap or play a video game. The ones who napped scored consistently higher than those who stayed awake. The study may help scientists learn more about what happens when people go to sleep. They already know that the brain undergoes a number of significant changes in the process. "There are dramatic shifts in brain chemistry and electrophysiology," said Dr. Matthew Tucker, researcher at Harvard University School of Medicine and the Center for Sleep and Cognition. "For example, we know that levels of the transmitter acetylcholine go down. And we think that when acetylcholine gets to a low point, it should have an enhancing effect on memory."
Experts believe that sleeping is the brain's chance to decide which details and memories from the day need to be placed in permanent storage and which ones need to be thrown out. It has to do this because there is only so much room in the brain for information. Of course, those catnaps may be wonderful, but they can never replace the value of a solid eight hours of sleep. As Dr. Olaf Lahl, the study's lead author, remarks, "A regular sleep schedule still plays an important role in overall well-being and health."dy, however, has shown that if you really want to refresh your brain, a six-minute catnap will do it. Not only will you feel better afterward, but your ability to learn and remember will have improved as well. As described in a recent article in the Journal of Sleep Research, students at the University of Dusseldorf participated in experiments in which they had to memorize a list of words and then either take a nap or play a video game. The ones who napped scored consistently higher than those who stayed awake. The study may help scientists learn more about what happens when people go to sleep. They already know that the brain undergoes a number of significant changes in the process. “There are dramatic shifts in brain chemistry and electrophysiology,†said Dr. Matthew Tucker, researcher at Harvard University School of Medicine and the Center for Sleep and Cognition. “For example, we know that levels of the transmitter acetylcholine go down. And we think that when acetylcholine gets to a low point, it should have an enhancing effect on memory.†Experts believe that sleeping is the brain's chance to decide which details and memories from the day need to be placed in permanent storage and which ones need to be thrown out. It has to do this because there is only so much room in the brain for information. Of course, those catnaps may be wonderful, but they can never replace the value of a solid eight hours of sleep. As Dr. Olaf Lahl, the study's lead author, remarks, “A regular sleep schedule still plays an important role in overall well-being and health.â€
What is the meaning of the word 'shifts' as used in the third paragraph?
Correct Answer: A
Rationale: In this context, 'shifts' refers to changes or alterations in brain chemistry and electrophysiology. The word 'alterations' best captures the idea that significant changes are occurring in the brain. 'Stints' (choice B) refer to short periods of time or work, which is not the meaning intended here. 'Removals' (choice C) and 'transfers' (choice D) do not fit the context of the sentence and are not related to the changes happening in the brain as described in the extract.
Nokea