Scientists researching hypnosis have uncovered evidence that counters some of the skepticism about the technique. One skeptical

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问题     Scientists researching hypnosis have uncovered evidence that counters some of the skepticism about the technique. One skeptical hypothesis is that hypnosis may be the product of "vivid imagination", a now discredited charge stemming from the observation that many people who are hypnotizable can be led to experience compellingly realistic auditory and visual hallucinations. Nothing that an auditory hallucination and the act of imagining a sound are both self-generated and that,like real hearing,a hallucination is experienced as the product of an external source, Henry Szechtman used PET (positron emission tomography) to image the brain activity of hypnotized subjects invited to imagine a scenario and then experiencing a hallucination. By monitoring regional blood flow in areas activated during both hearing and auditory hallucination but not during simple imagining, the investigators sought to determine where in the brain a hallucinated sound is mistakenly "tagged"as authentic and originating in the outside world.
    Szechtman imaged the brain activity of eight very hypnotizable subjects who had been prescreened for their ability to hallucinate under hypnosis. During the session,the subjects were under hypnosis and lay in the PET scanner with their brain activity being monitored under four conditions:at rest;while hearing an audiotape of a voice,while imagining hearing the voice again;and during the auditory hallucination they experienced after being informed that the tape was playing once more,although it was not. The tests suggested that a region of the brain called the right anterior cingulate cortex was just as active while the vol-unteers were hallucinating as it was while they were actually hearing the stimulus. In contrast, that brain area remained dormant while the subjects were imagining that they heard the stimulus.
    The second major objection raised by critics argues that hypnosis’ ability to blunt pain results from either simple relaxation or a placebo response. McGlashan established that while hypnosis was only as effective in reducing pain as a sugar pill for poorly hypnotizable people,highly hypnotizable subjects benefited three times more from hypnosis than from the placebo. In response to these successes,Rainville devised experiments to determine which brain structures are involved in pain relief during hypnosis,attempting to locate the brain structures associated with the suffering component of pain,as distinct from its sensory aspects. Using PET, he and other scientists found that hypnosis reduced the activity of the anterior cingulate cortex—an area known to be involved in pain—but did not affect the activity of the somatosensory cortex, where the sensations of pain are processed.
    Despite the value of these findings,the mechanisms underlying hypnotic pain relief are still poorly understood. The model favored by most researchers is that the analgesic effect of hypnosis occurs in higher brain centers than those involved in registering the painful sensation, accounting for the fact that most autonomic responses that routinely accompany pain—such as increased heart rate—are relatively unaffected by hypnotic suggestions of analgesia.
According to the passage,which of the following is one of the primary factors that led researchers studying hypnosis to compare auditory hallucinations and imagined sounds?

选项 A、The high level of realism involved in auditory hallucinations but not in the experience of external sounds.
B、The observed similarities between visual and auditory hallucinations in hypnotized subjects.
C、The fact that both auditory hallucinations and simple imagining are generated by the research subjects.
D、The blood flow in areas activated by simple imagining but not by auditory hallucination.

答案D

解析 推理题。解题点在文章第一段最后一句。文章提到“By monitoring regional blood flow in areas activated during both hearing and auditory hallucination but not during simple imagining,the investigators sought to determine…”,可知通过监视不同条件下的局部血流量,研究人员试图找到幻听和想象的声音之间的区别,所以正确答案是D选项。
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