In the new movie, 'Inception,' a master thief is able to infiltrate peoples' dreams and steal their subconscious secrets -- even plant a dream idea they'll think is their own.

As fantastical as that seems, an evolving area of sleep research holds that it is possible for people to direct their own dreams, in a limited way.

For example, people who suffer from recurring nightmares can learn to substitute happier endings. Practitioners of lucid dreaming -- who train themselves to be aware that they are dreaming -- say they can try out fantasies like flying.

Ordering up a dream about a nagging personal problem is difficult, but possible, says Robert Stickgold, an associate professor of psychiatry at Harvard Medical School. 'As you go to bed tonight, really think about some of those emotional" target="_blank" title="a.易动感情的；情感的">emotional issues that you haven't wanted to deal with. You've got about a 10% to 20% shot.'

That fits with the current understanding of what dreams are and why we have them. Once thought to represent repressed sexual urges, or simply neurons firing randomly, dreams are now believed to be mash-ups created by the unconscious mind as it processes, sorts and stores emotions from the day.

'We take our problems to sleep and we work through them during the night,' says Rosalind Cartwright, an emeritus professor of neuroscience at Rush University Medical Center in Chicago, who has spent nearly 50 years studying sleep and dreams.

Her new book, 'The Twenty-Four Hour Mind,' explains that the mind latches onto some thread of unfinishedemotional" target="_blank" title="a.易动感情的；情感的">emotional business from the day. Then, in REM sleep (the rapid eye movement period when most dreaming occurs), it calls up bits of older memories that are somehow related, and melds them together. 'That's why dreams look so peculiar. You have old memories and new memories Scotch-plaided into each other,' she says. 'They are emotional" target="_blank" title="a.易动感情的；情感的">emotional connections rather than logical ones.'

Usually, people work through the most negativeemotions first, and their dreams become more positive as the night goes on. (How do researchers know that? 'The old-fashioned way. We wake them up and ask them,' Dr. Cartwright says.)

But nightmares interrupt that process; people usually wake up before the frightening emotion is resolved, so the dream keeps repeating.

'Your brain seems to think that it's helping you to prepare, but you don't allow yourself to finish it so it becomes a broken record,' says Shelby Freedman Harris, director of the Behavioral Sleep Medicine Program at Montefiore Medical Center in Bronx, N.Y.

Dr. Harris's program is one of a small number around the country that helps nightmare sufferers and people with post-traumatic stressdisorder learn to rewrite the script of their recurring dreams using a technique called Image Rehearsal Therapy.

After recalling the nightmare in detail, the dreamer writes out the new script and envisions it several times a day. Dr. Harris says one of her patients had recurring nightmares of being surrounded by sharks. She imagined they were dolphins instead and rehearsed the scene during five sessions, and the nightmares vanished. A young patient having nightmares of being chased turned the pursuer into chocolate and ate him.

'It gives the patient control over the nightmare,' says Dr. Harris. Studies have found that after several sessions practicing with a therapist, some patients dream the new ending just as they envision it, some dream another version of it, and some stop having the nightmare altogether.

Can you order up a dream on a specific topic, or can somebody else influence your dreams? Numerous experiments with so-called dream incubation have tried, with mixed results.

'I can control people's dreams. I can get them to dream about videogames by having them play intensely,' says Dr. Stickgold. His studies at Harvard found that when volunteers played the game Tetris for hours a day, 60% reported dreaming about it at least once as they were falling asleep.

In a follow-up study with the virtual-skiing game Alpine Racer, 14 of 16 students reported seeing skiing images at sleep onset (as did three people who were merely observing the experiment.)

It's unclear how far into the night's dreams those images persisted. Dr. Stickgold and colleagues are now repeating the study having subjects play 'Dance, Dance Revolution' and waking them later in the night to ask about their dreams.

Melinda Beck

• research [ri´sə:tʃ] n.&vi.调查；探究；研究 (初中英语单词)
• substitute [´sʌbstitju:t] n.代理人 v.代替，取代 (初中英语单词)
• associate [ə´səuʃieit] v.联合a.同伴的n.伙伴 (初中英语单词)
• medical [´medikəl] a.医学的；医疗的 (初中英语单词)
• emotional [i´məuʃənəl] a.易动感情的；情感的 (初中英语单词)
• movement [´mu:vmənt] n.活动；运动；动作 (初中英语单词)
• peculiar [pi´kju:liə] a.特有的；奇异的 (初中英语单词)
• old-fashioned [´əuld´feʃənd] a.老式的；过时的 (初中英语单词)
• interrupt [,intə´rʌpt] v.中断；打扰 (初中英语单词)
• emotion [i´məuʃən] n.感情；情绪；激动 (初中英语单词)
• director [di´rektə] n.指导者；....长；导演 (初中英语单词)
• program [´prəugræm] n.说明v.为...安排节目 (初中英语单词)
• stress [stres] n.强调；压力 vt.强调 (初中英语单词)
• limited [´limitid] a.有限(制)的 (高中英语单词)
• harvard [´hɑ:vəd] n.哈佛大学 (高中英语单词)
• unconscious [ʌn´kɔnʃəs] a.无意识的；不觉察的 (高中英语单词)
• related [ri´leitid] a.叙述的；有联系的 (高中英语单词)
• negative [´negətiv] a.否定的 n.否定词 (高中英语单词)
• positive [´pɔzətiv] a.确定的 (高中英语单词)
• disorder [dis´ɔ:də] n.杂乱 vt.扰乱 (高中英语单词)
• ending [´endiŋ] n.结尾，结局 (高中英语单词)
• specific [spi´sifik] a.具体的；特有的 (高中英语单词)
• so-called [´sou ´kɔ:ld] a.所谓的，号称的 (高中英语单词)
• seeing [si:iŋ] see的现在分词 n.视觉 (高中英语单词)
• chicago [ʃi´kɑ:gəu] n.芝加哥 (英语四级单词)
• unfinished [´ʌn´finiʃt] a.未完成的，未完工的 (英语四级单词)
• logical [´lɔdʒikəl] a.逻辑(上)的 (英语四级单词)
• resolved [ri´zɔlvd] a.决心的；坚定的 (英语四级单词)
• nightmare [´naitmeə] n.梦魇；恶梦 (英语四级单词)
• rehearsal [ri´hə:səl] v.(使)排练；背诵 (英语四级单词)
• version [´və:ʃən, ´və:rʒən] n.翻译；说明；译本 (英语四级单词)
• alpine [´ælpain] a.高山的 (英语四级单词)
• sexual [´sekʃuəl] a.性(欲)的 (英语六级单词)
• script [skript] n.笔迹；手稿；剧本 (英语六级单词)
• technique [tek´ni:k] n.技术；技巧；方法 (英语六级单词)
• dreamer [´dri:mə] n.做梦的人；梦想者 (英语六级单词)
• pursuer [pə´sju:ə] n.追赶者；追求者；从事者 (英语六级单词)