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Steering clear of tip-of-the-tongue experiences
SCIENCE AND MEDICINE
Steering clear of tip-of-the-tongue experiences
T
he ability to retrieve a word that is on the “tip of the tongue” depends on memory of both a word’s meaning and its sound, says Deborah Burke (Pomona College, Claremont, CA, USA). “Names are the worst. You can remember everything about the person—all that’s missing is the sound. And so tip-of-the tongue experiences result in the well-known situation of ‘I’ll never forget what’s her name’”, she quips. Burke and colleague Lori James asked 108 study participants a series of questions designed to provoke a high rate of tip-of-the tongue experiences because the answers were seldom-used words or names (for example, “what word means to formally renounce a throne?”). Pronouncing “priming” words that shared at least one phonological feature of the target word beforehand (for example, saying the word “abstract” before being queried for the target word
“abdicate”) led to fewer wordfinding errors overall than did pronouncing words that did not
Maintain those language skills!
have a sound similar to the target. Subsequently, 28 participants were “primed” only when they had a tip-the-tongue experience; 21 were more likely to retrieve the word after priming (J Exp Psychol Learn Mem Cogn 2000; 26: 1378–91). Tip-of-tongue experiences are “completely normal” for seldom-
Robots mimic monkeys—promise for paralysis? ontrolling robots by the power of thought was “once in the realm of science fiction”, says Sandro MussaIvaldi (Northwestern University Medical School, Chicago, USA). But a new report of robot arms driven by real-time cortical signals in monkeys brings this goal closer to reality. Ultimately, explains lead author Miguel Nicolelis (Duke University, Durham, NC, USA), “we are looking for a brain–machine interface for use in many clinical situations”. Initially, his team used arrays of microelectrodes to directly record cortical activity from large populations of neurons in two owl monkeys while they were trained to do one-dimensional and three-dimensional motor tasks. Then, the group applied different algorithms to real-time cortical activity in an attempt to predict the monkeys’ arm movements. For both motor tasks, even a simple linear algorithm successfully predicted subsequent movements. This system was then used to enable two robot arms—one local and one hundreds of miles away—to mimic the monkeys’ movements in real-time (Nature 2000; 408: 361–65). Although Nicolelis cautions that there are “many steps ahead”, he is enthusiastic about the future potential of the technology to restore voluntary
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THE LANCET • Vol 356 • 18 November, 2000
control of paralysed limbs. He speculates that an intracerebral implant to collect, process, and transmit activity from ensembles of cortical neurons could one day be used to bypass spinal cord lesions “by acquiring a signal directly from the motor cortex and feeding it into nerves of paralysed limbs”. And for patients who have muscle atrophy or peripheral degeneration, Nicolelis envisages the same implant driving a robotic prosthetic limb. His team is now studying the system in Rhesus monkeys, the final stage of study before planning clinical trials. However, he cautions that before human trials can begin, the potential applications will need to be evaluated with the risks and costs of the procedure and the community reaction to such technology. In a commentary, Mussa-Ivaldi also points out the potential of such “neurorobotic systems” to further reveal the workings of the brain, including the functions of specific cortical areas, and whether and how neurons can be “programmed”. Artificial devices that test the learning ability of real neuronal networks may also provide insights into the fundamental mechanisms of biological learning.
used words, although the incidence of such experiences increases with age, says Burke. By contrast, in disorders such as Alzheimer’s disease, word-finding failures occur for common words and names of close relatives, indicating that a different mechanism may be at work. Older adults should keep up their language skills by doing crossword puzzles and anagrams, playing Scrabble, and interacting with others, emphasises Burke. “Otherwise, they may fall into a vicious cycle: they start having trouble with names, they avoid settings such as the dining hall in the retirement community because there are so many people whose names they don’t remember, and they end up eating alone in their rooms. The more they pull back from social interaction, the more word-finding problems they are likely to have”, she warns. Marilynn Larkin
News in brief Oesophageal cancer: genetic biomarker discovered A biomarker, an altered gene APC, can be detected and measured in oesophageal tumours and in the patient’s bloodstream. Measuring this biomarker will help doctors more accurately determine the stage of the cancer, monitor the effectiveness of treatment, and check for recurrence of disease, the authors propose. They found that APC, a tumour suppressor gene, was deactivated in most of the patients. When high levels of the altered gene were present in the bloodstream, survival rate was low (J Natl Can Inst 2000: Nov 15). Success of bypass-surgery prediction An advance in magnetic resonance imaging from the USA has improved the ability to determine which patients with coronaryartery disease will benefit from bypass surgery or angioplasty. The new technique enables doctors to assess damage to the heart wall, thus distinguishing between reversible and irreversible heart injury—important when making surgical decisions (N Engl J Med 2000; 343: Nov 16).
Kelly Morris
1743
For personal use only. Not to be reproduced without permission of The Lancet.
Steering clear of tip-of-the-tongue experiences
T
he ability to retrieve a word that is on the “tip of the tongue” depends on memory of both a word’s meaning and its sound, says Deborah Burke (Pomona College, Claremont, CA, USA). “Names are the worst. You can remember everything about the person—all that’s missing is the sound. And so tip-of-the tongue experiences result in the well-known situation of ‘I’ll never forget what’s her name’”, she quips. Burke and colleague Lori James asked 108 study participants a series of questions designed to provoke a high rate of tip-of-the tongue experiences because the answers were seldom-used words or names (for example, “what word means to formally renounce a throne?”). Pronouncing “priming” words that shared at least one phonological feature of the target word beforehand (for example, saying the word “abstract” before being queried for the target word
“abdicate”) led to fewer wordfinding errors overall than did pronouncing words that did not
Maintain those language skills!
have a sound similar to the target. Subsequently, 28 participants were “primed” only when they had a tip-the-tongue experience; 21 were more likely to retrieve the word after priming (J Exp Psychol Learn Mem Cogn 2000; 26: 1378–91). Tip-of-tongue experiences are “completely normal” for seldom-
Robots mimic monkeys—promise for paralysis? ontrolling robots by the power of thought was “once in the realm of science fiction”, says Sandro MussaIvaldi (Northwestern University Medical School, Chicago, USA). But a new report of robot arms driven by real-time cortical signals in monkeys brings this goal closer to reality. Ultimately, explains lead author Miguel Nicolelis (Duke University, Durham, NC, USA), “we are looking for a brain–machine interface for use in many clinical situations”. Initially, his team used arrays of microelectrodes to directly record cortical activity from large populations of neurons in two owl monkeys while they were trained to do one-dimensional and three-dimensional motor tasks. Then, the group applied different algorithms to real-time cortical activity in an attempt to predict the monkeys’ arm movements. For both motor tasks, even a simple linear algorithm successfully predicted subsequent movements. This system was then used to enable two robot arms—one local and one hundreds of miles away—to mimic the monkeys’ movements in real-time (Nature 2000; 408: 361–65). Although Nicolelis cautions that there are “many steps ahead”, he is enthusiastic about the future potential of the technology to restore voluntary
C
THE LANCET • Vol 356 • 18 November, 2000
control of paralysed limbs. He speculates that an intracerebral implant to collect, process, and transmit activity from ensembles of cortical neurons could one day be used to bypass spinal cord lesions “by acquiring a signal directly from the motor cortex and feeding it into nerves of paralysed limbs”. And for patients who have muscle atrophy or peripheral degeneration, Nicolelis envisages the same implant driving a robotic prosthetic limb. His team is now studying the system in Rhesus monkeys, the final stage of study before planning clinical trials. However, he cautions that before human trials can begin, the potential applications will need to be evaluated with the risks and costs of the procedure and the community reaction to such technology. In a commentary, Mussa-Ivaldi also points out the potential of such “neurorobotic systems” to further reveal the workings of the brain, including the functions of specific cortical areas, and whether and how neurons can be “programmed”. Artificial devices that test the learning ability of real neuronal networks may also provide insights into the fundamental mechanisms of biological learning.
used words, although the incidence of such experiences increases with age, says Burke. By contrast, in disorders such as Alzheimer’s disease, word-finding failures occur for common words and names of close relatives, indicating that a different mechanism may be at work. Older adults should keep up their language skills by doing crossword puzzles and anagrams, playing Scrabble, and interacting with others, emphasises Burke. “Otherwise, they may fall into a vicious cycle: they start having trouble with names, they avoid settings such as the dining hall in the retirement community because there are so many people whose names they don’t remember, and they end up eating alone in their rooms. The more they pull back from social interaction, the more word-finding problems they are likely to have”, she warns. Marilynn Larkin
News in brief Oesophageal cancer: genetic biomarker discovered A biomarker, an altered gene APC, can be detected and measured in oesophageal tumours and in the patient’s bloodstream. Measuring this biomarker will help doctors more accurately determine the stage of the cancer, monitor the effectiveness of treatment, and check for recurrence of disease, the authors propose. They found that APC, a tumour suppressor gene, was deactivated in most of the patients. When high levels of the altered gene were present in the bloodstream, survival rate was low (J Natl Can Inst 2000: Nov 15). Success of bypass-surgery prediction An advance in magnetic resonance imaging from the USA has improved the ability to determine which patients with coronaryartery disease will benefit from bypass surgery or angioplasty. The new technique enables doctors to assess damage to the heart wall, thus distinguishing between reversible and irreversible heart injury—important when making surgical decisions (N Engl J Med 2000; 343: Nov 16).
Kelly Morris
1743
For personal use only. Not to be reproduced without permission of The Lancet.