VOA慢速英語:研究發(fā)現(xiàn)咖啡因有助于增加長期記憶

[00:00.00]From VOA Learning English, [00:02.88]this is the Health Report. [00:05.42]Many people say they can not start their day [00:09.30]without first having a cup of coffee or tea. [00:13.83]People say these drinks help them think clearly [00:17.56]and feel more awake. [00:20.15]This is because of caffeine, [00:23.14]a substance found in some plants. [00:26.62]Caffeine helps to give a jumpstart to the nervous system. [00:32.54]Now a new report says it may also improve long-term memory. [00:39.41]The report was published earlier this year [00:42.55]in the journal Nature Neuroscience. [00:45.83]Michael Yassa is a neurobiology professor [00:49.71]at the University of California, Irvine. [00:53.15]He and other researchers wanted to know [00:56.73]if caffeine could improve what they called memory consolidation. [01:02.59]They asked a group of individuals to learn something new, [01:07.87]then the same people were given caffeine, [01:11.95]the active ingredient in coffee, tea and chocolate. [01:18.04]He and the other researchers worked [01:21.40]with a group of 160 people who were caffeine free. [01:26.33]On the first day, [01:28.32]all the subjects were shown pictures of everyday objects. [01:33.89]They were asked to identify whether the pictures [01:38.08]could be found inside the house or outdoors. [01:42.76]Some of the subjects were then given a caffeine pill, [01:47.97]the others were given a placebo [01:50.76]- a pill containing an inactive substance. [01:54.65]On the second day, all of the subjects [01:58.13]were asked to look at more pictures. [02:01.02]Some of the images were exactly like the ones [02:05.00]they had seen 24 hours early. [02:08.38]But other images were different. [02:11.32]And a third group of pictures [02:14.10]was similar to the first group but a little different. [02:19.18]The participants had to decide whether the images they saw [02:24.42]were the same or different from the ones on the first day. [02:30.29]Professor Yassa says their answers [02:33.08]help to show the effects of caffeine on memory. [02:37.60]He says those who took the caffeine pills [02:40.64]had a ten to twelve percent increase [02:44.07]in their ability to remember the objects. [02:48.20]The amount of caffeine the researchers used in the study [02:52.28]was similar to one strong cup of coffee. [02:56.32]Professor Yassa says pills [02:59.15]with a little more coffeine also increased memory, [03:03.18]but resulted in some participants appearing more nervous. [03:08.56]And that's the Health Report from VOA Learning English. [03:13.93]For more stories about health, [03:16.97]go to our website 51voa.com. [03:24.00]I'm Christopher Cruise.

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