human
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: OBJECTIVES Stimulant medications appear effective at restoring simple alertness and psychomotor vigilance in sleep deprived individuals , but it is not clear whether these medications are effective at restoring higher order complex cognitive capacities such as planning , sequencing , and decision making . DESIGN After 44 hours awake , participants received a double-blind dose of one of 3 stimulant medications or placebo . After 45 - 50 hours awake , participants were tested on computerized versions of the 5-Ring Tower of Hanoi ( TOH ) , the Tower of London ( TOL ) , and the Wisconsin Card Sorting Test ( WCST ) .  SETTING In-residence sleep-laboratory facility at the Walter Reed Army Institute of Research . PARTICIPANTS Fifty-four healthy adults ( 29 men , 25 women ) , ranging in age from 18 to 36 years . INTERVENTIONS Participants were r and omly assigned to 1 of 3 stimulant medication groups , including caffeine , 600 mg ( n=12 ) , modafinil , 400 mg ( n=12 ) , dextroamphetamine , 20 mg ( n=16 ) , or placebo ( n=14 ) . MEASUREMENTS AND RESULTS At the doses tested , modafinil and dextroamphetamine groups completed the TOL task in significantly fewer moves than the placebo group , and the modafinil group demonstrated greater deliberation before making moves . In contrast , subjects receiving caffeine completed the TOH in fewer moves than all 3 of the other groups , although speed of completion was not influenced by the stimulants . Finally , the modafinil group outperformed all other groups on indices of perseverative responding and perseverative errors from the WCST . CONCLUSIONS Although comparisons across tasks can not be made due to the different times of administration , within-task comparisons suggest that , at the doses tested here , each stimulant may produce differential advantages depending on the cognitive dem and s of the task Abstract Rationale . Modafinil , a novel wake-promoting agent , has been shown to have a similar clinical profile to that of conventional stimulants such as methylpheni date . We were therefore interested in assessing whether modafinil , with its unique pharmacological mode of action , might offer similar potential as a cognitive enhancer , without the side effects commonly experienced with amphetamine-like drugs . Objectives . The main aim of this study was to evaluate the cognitive enhancing potential of this novel agent using a comprehensive battery of neuropsychological tests . Methods . Sixty healthy young adult male volunteers received either a single oral dose of placebo , or 100 mg or 200 mg modafinil prior to performing a variety of tasks design ed to test memory and attention . A r and omised double-blind , between-subjects design was used . Results . Modafinil significantly enhanced performance on tests of digit span , visual pattern recognition memory , spatial planning and stop-signal reaction time . These performance improvements were complemented by a slowing in latency on three tests : delayed matching to sample , a decision-making task and the spatial planning task . Subjects reported feeling more alert , attentive and energetic on drug . The effects were not clearly dose dependent , except for those seen with the stop-signal paradigm . In contrast to previous findings with methylpheni date , there were no significant effects of drug on spatial memory span , spatial working memory , rapid visual information processing or attentional set-shifting . Additionally , no effects on paired associates learning were identified . Conclusions . These data indicate that modafinil selectively improves neuropsychological task performance . This improvement may be attributable to an enhanced ability to inhibit pre-potent responses . This effect appears to reduce impulsive responding , suggesting that modafinil may be of benefit in the treatment of attention deficit hyperactivity disorder The authors present a unified account of 2 neural systems concerned with the development and expression of adaptive behaviors : a mesencephalic dopamine system for reinforcement learning and a " generic " error-processing system associated with the anterior cingulate cortex . The existence of the error-processing system has been inferred from the error-related negativity ( ERN ) , a component of the event-related brain potential elicited when human participants commit errors in reaction-time tasks . The authors propose that the ERN is generated when a negative reinforcement learning signal is conveyed to the anterior cingulate cortex via the mesencephalic dopamine system and that this signal is used by the anterior cingulate cortex to modify performance on the task at h and . They provide support for this proposal using both computational modeling and psychophysiological experimentation Abstract . Rationale : In 1998 , the FDA approved modafinil for treating  excessive daytime sleepiness in narcoleptics , and this has raised questions about the appropriateness of this compound for enhancing alertness in sleep-deprived controls . This study explored the efficacy of modafinil for maintaining the performance of volunteers required to accomplish highly dem and ing tasks despite sleep loss . Objective : The principal objective was to determine whether prophylactic doses of modafinil would attenuate decrements in aviator performance and arousal throughout 2 days and 1 night without sleep . Methods : Six pilots were exposed to two 40-h periods of continuous wakefulness . In one , three 200-mg doses of modafinil were given and in the other , matching placebos were administered . Helicopter simulator flights , resting EEGs , and Profile of Mood States ( POMS ) question naires were evaluated . Results : Modafinil attenuated sleep deprivation effects on four of six flight maneuvers , reduced slow-wave EEG activity , and lessened self-reported problems with mood and alertness in comparison to placebo . The most noticeable benefits occurred between 0330 and 1130 hours , when the combined impact of sleep loss and the circadian trough was most severe . The most frequently observed drug side effects were vertigo , nausea , and dizziness . These could have been related to : 1 ) the motion-based testing , 2 ) the use of a simulator rather than an actual aircraft ( i.e. , " simulator sickness " ) , and /or 3 ) the administration of more than 400 mg modafinil . Conclusions : Modafinil is a promising countermeasure for  sleep loss in normals ; however , additional studies aim ed at reducing side effects are needed before it should be used in aviators BACKGROUND Response inhibition is an executive function that requires voluntary control over responses when there is a change of context . The right inferior frontal cortex is necessary for response inhibition , and a deficit in right frontostriatal circuitry might underlie attention-deficit/hyperactivity disorder ( ADHD ) . Many studies of childhood ADHD have demonstrated impaired response inhibition and its amelioration by methylpheni date ( MPH ) . The current study tested response inhibition and the effect of MPH in adult ADHD . METHODS Response inhibition was assessed with the " tracking " stop-signal test in 13 adults with a diagnosis of ADHD , both while taking and while not taking medication , and 13 healthy , unmedicated , age- and intelligence quotient-matched control subjects . RESULTS Stop-signal reaction time was significantly slower in unmedicated adults with ADHD relative to healthy control subjects , and this deficit was significantly ameliorated by medication . CONCLUSIONS Adult ADHD patients had a response inhibition profile similar to that produced by lesions to the right inferior frontal cortex , which was remedied by stimulant medication Nonmedical use of prescription-stimulant medication such as methylpheni date ( MPH ) has increased among college students over the past several years . Common motivations for use include enhancements in cognition and subjective arousal . As it is unclear whether stimulant medication exerts the same effect on healthy individuals as for those with attention-deficit/hyperactivity disorder , it is possible that many reported effects of prescription stimulants by healthy individuals may stem from placebo effects , which may be an important mechanism underlying initiation and maintenance of nonmedical use . This study examined whether placebo effects influence reports of subjective mood and cognitive performance among college students who endorsed several risk factors for prescription-stimulant misuse ( i.e. , low grade point average , fraternity/sorority involvement , binge drinking , cannabis use ) . Ninety-six subjects ( 60 % male ) completed cognitive tests and question naires assessing present mood state on two occasions . Forty-seven participants were r and omized to an experimental condition and orally ingested what they believed to be MPH , though actually placebo , on one visit and received no medication on the other visit . The control group received no medication on either visit . During the administration visit , experimental participants reported feeling significantly more high and stimulated compared with the nonadministration visit and to the control subjects . However , cognitive enhancement differences were not generally seen between visits or groups . This research demonstrates that placebo effects for prescription stimulants do influence subjective mood and may be implicated in nonmedical stimulant use . This knowledge may be useful in challenging prescription-stimulant-related expectancies to decrease the prevalence of use among college students How the brain monitors ongoing behavior for performance errors is a central question of cognitive neuroscience . Diminished awareness of performance errors limits the extent to which humans engage in corrective behavior and has been linked to loss of insight in a number of psychiatric syndromes ( e.g. , attention deficit hyperactivity disorder , drug addiction ) . These conditions share alterations in monoamine signaling that may influence the neural mechanisms underlying error processing , but our underst and ing of the neurochemical drivers of these processes is limited . We conducted a r and omized , double-blind , placebo-controlled , cross-over design of the influence of methylpheni date , atomoxetine , and citalopram on error awareness in 27 healthy participants . The error awareness task , a go/no-go response inhibition paradigm , was administered to assess the influence of monoaminergic agents on performance errors during fMRI data acquisition . A single dose of methylpheni date , but not atomoxetine or citalopram , significantly improved the ability of healthy volunteers to consciously detect performance errors . Furthermore , this behavioral effect was associated with a strengthening of activation differences in the dorsal anterior cingulate cortex and inferior parietal lobe during the methylpheni date condition for errors made with versus without awareness . Our results have implication s for the underst and ing of the neurochemical underpinnings of performance monitoring and for the pharmacological treatment of a range of disparate clinical conditions that are marked by poor awareness of errors Psychostimulants such as mixed amphetamine salts ( MAS , br and name Adderall ) are widely used for cognitive enhancement by healthy young people , yet laboratory research on effectiveness has yielded variable results . The present study assessed the effects of MAS in healthy young adults with an adequately powered double-blind cross-over placebo-controlled trial . We examined effects in 13 measures of cognitive ability including episodic memory , working memory , inhibitory control , convergent creativity , intelligence and scholastic achievement  , with the goals of determining ( 1 ) whether the drug is at least moderately enhancing ( Cohen 's d > = .5 ) to some or all cognitive abilities tested , ( 2 ) whether its effects on cognition are moderated by baseline ability or COMT genotype , and ( 3 ) whether it induces an illusory perception of cognitive enhancement . The results did not reveal enhancement of any cognitive abilities by MAS for participants in general . There was a suggestion of moderation of enhancement by baseline ability and COMT genotype in a minority of tasks , with MAS enhancing lower ability participants on word recall , embedded figures and Raven 's Progressive Matrices . Despite the lack of enhancement observed for most measures and most participants , participants nevertheless believed their performance was more enhanced by the active capsule than by placebo . We conclude that MAS has no more than small effects on cognition in healthy young adults , although users may perceive the drug as enhancing their cognition . This article is part of a Special Issue entitled ' Cognitive Enhancers ' OBJECTIVES To explore the illicit use of specific prescription stimulants among college students and add to our underst and ing of reasons ( motives ) and routes of administration associated with illicit use of these drugs . METHODS A r and om sample of 4580 college students self-administered a Web-based survey . The survey contained a variety of items pertaining to the illicit use of prescription stimulants . An extensive list of prescription stimulants was provided , and students were asked to select all the specific prescription stimulants that they had used illicitly . Items were also included to assess the motives and routes of administration associated with illicit use of prescription stimulants . RESULTS Lifetime and past-year prevalence rates for illicit use of prescription stimulants were 8.3 % ( 382 students ) and 5.9 % ( 269 students ) , respectively . Approximately three fourths ( 75.8 % ) of the 269 past-year illicit users of prescription stimulants reported using an amphetamine-dextroamphetamine combination agent ( e.g. , Adderall ) in the past year , and approximately one fourth ( 24.5 % ) reported using methylpheni date ( e.g. , Ritalin , Concerta , Meta date , Methylin ) . Past-year illicit use of prescription stimulants was more than 3 times more likely among Caucasians ( odds ratio [ OR ] 3.1 , 95 % confidence interval [ CI ] 1.5 - 6.6 ) and Hispanics ( OR 3.8 , 95 % CI 1.6 - 9.3 ) compared with African-Americans , and more than twice as likely among Caucasians ( OR 2.1 , 95 % CI 1.3 - 3.4 ) and Hispanics ( OR 2.6 , 95 % CI 1.4 - 5.1 ) compared with A 
    Output:
    
agent
RESULTS Modafinil appears to improve reaction time ( P ≤ 0.04 ) , logical reasoning ( P ≤ 0.05 ) and problem-solving .
Across all three types of prescription stimulants , research shows improved attention with lack of consensus on whether these improvements are limited to simple versus complex tasks in varying youth population s. CONCLUSIONS The heterogeneity of the non-attention deficit hyperactivity disorder youth population , the variation in cognitive task characteristics and lack of replication of studies makes assessing the potential global neurocognitive benefits of stimulants among non-attention deficit hyperactivity disorder youth difficult ; however , some youth may derive benefit in specific cognitive domains
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: OBJECTIVES Stimulant medications appear effective at restoring simple alertness and psychomotor vigilance in sleep deprived individuals , but it is not clear whether these medications are effective at restoring higher order complex cognitive capacities such as planning , sequencing , and decision making . DESIGN After 44 hours awake , participants received a double-blind dose of one of 3 stimulant medications or placebo . After 45 - 50 hours awake , participants were tested on computerized versions of the 5-Ring Tower of Hanoi ( TOH ) , the Tower of London ( TOL ) , and the Wisconsin Card Sorting Test ( WCST ) .  SETTING In-residence sleep-laboratory facility at the Walter Reed Army Institute of Research . PARTICIPANTS Fifty-four healthy adults ( 29 men , 25 women ) , ranging in age from 18 to 36 years . INTERVENTIONS Participants were r and omly assigned to 1 of 3 stimulant medication groups , including caffeine , 600 mg ( n=12 ) , modafinil , 400 mg ( n=12 ) , dextroamphetamine , 20 mg ( n=16 ) , or placebo ( n=14 ) . MEASUREMENTS AND RESULTS At the doses tested , modafinil and dextroamphetamine groups completed the TOL task in significantly fewer moves than the placebo group , and the modafinil group demonstrated greater deliberation before making moves . In contrast , subjects receiving caffeine completed the TOH in fewer moves than all 3 of the other groups , although speed of completion was not influenced by the stimulants . Finally , the modafinil group outperformed all other groups on indices of perseverative responding and perseverative errors from the WCST . CONCLUSIONS Although comparisons across tasks can not be made due to the different times of administration , within-task comparisons suggest that , at the doses tested here , each stimulant may produce differential advantages depending on the cognitive dem and s of the task Abstract Rationale . Modafinil , a novel wake-promoting agent , has been shown to have a similar clinical profile to that of conventional stimulants such as methylpheni date . We were therefore interested in assessing whether modafinil , with its unique pharmacological mode of action , might offer similar potential as a cognitive enhancer , without the side effects commonly experienced with amphetamine-like drugs . Objectives . The main aim of this study was to evaluate the cognitive enhancing potential of this novel agent using a comprehensive battery of neuropsychological tests . Methods . Sixty healthy young adult male volunteers received either a single oral dose of placebo , or 100 mg or 200 mg modafinil prior to performing a variety of tasks design ed to test memory and attention . A r and omised double-blind , between-subjects design was used . Results . Modafinil significantly enhanced performance on tests of digit span , visual pattern recognition memory , spatial planning and stop-signal reaction time . These performance improvements were complemented by a slowing in latency on three tests : delayed matching to sample , a decision-making task and the spatial planning task . Subjects reported feeling more alert , attentive and energetic on drug . The effects were not clearly dose dependent , except for those seen with the stop-signal paradigm . In contrast to previous findings with methylpheni date , there were no significant effects of drug on spatial memory span , spatial working memory , rapid visual information processing or attentional set-shifting . Additionally , no effects on paired associates learning were identified . Conclusions . These data indicate that modafinil selectively improves neuropsychological task performance . This improvement may be attributable to an enhanced ability to inhibit pre-potent responses . This effect appears to reduce impulsive responding , suggesting that modafinil may be of benefit in the treatment of attention deficit hyperactivity disorder The authors present a unified account of 2 neural systems concerned with the development and expression of adaptive behaviors : a mesencephalic dopamine system for reinforcement learning and a " generic " error-processing system associated with the anterior cingulate cortex . The existence of the error-processing system has been inferred from the error-related negativity ( ERN ) , a component of the event-related brain potential elicited when human participants commit errors in reaction-time tasks . The authors propose that the ERN is generated when a negative reinforcement learning signal is conveyed to the anterior cingulate cortex via the mesencephalic dopamine system and that this signal is used by the anterior cingulate cortex to modify performance on the task at h and . They provide support for this proposal using both computational modeling and psychophysiological experimentation Abstract . Rationale : In 1998 , the FDA approved modafinil for treating  excessive daytime sleepiness in narcoleptics , and this has raised questions about the appropriateness of this compound for enhancing alertness in sleep-deprived controls . This study explored the efficacy of modafinil for maintaining the performance of volunteers required to accomplish highly dem and ing tasks despite sleep loss . Objective : The principal objective was to determine whether prophylactic doses of modafinil would attenuate decrements in aviator performance and arousal throughout 2 days and 1 night without sleep . Methods : Six pilots were exposed to two 40-h periods of continuous wakefulness . In one , three 200-mg doses of modafinil were given and in the other , matching placebos were administered . Helicopter simulator flights , resting EEGs , and Profile of Mood States ( POMS ) question naires were evaluated . Results : Modafinil attenuated sleep deprivation effects on four of six flight maneuvers , reduced slow-wave EEG activity , and lessened self-reported problems with mood and alertness in comparison to placebo . The most noticeable benefits occurred between 0330 and 1130 hours , when the combined impact of sleep loss and the circadian trough was most severe . The most frequently observed drug side effects were vertigo , nausea , and dizziness . These could have been related to : 1 ) the motion-based testing , 2 ) the use of a simulator rather than an actual aircraft ( i.e. , " simulator sickness " ) , and /or 3 ) the administration of more than 400 mg modafinil . Conclusions : Modafinil is a promising countermeasure for  sleep loss in normals ; however , additional studies aim ed at reducing side effects are needed before it should be used in aviators BACKGROUND Response inhibition is an executive function that requires voluntary control over responses when there is a change of context . The right inferior frontal cortex is necessary for response inhibition , and a deficit in right frontostriatal circuitry might underlie attention-deficit/hyperactivity disorder ( ADHD ) . Many studies of childhood ADHD have demonstrated impaired response inhibition and its amelioration by methylpheni date ( MPH ) . The current study tested response inhibition and the effect of MPH in adult ADHD . METHODS Response inhibition was assessed with the " tracking " stop-signal test in 13 adults with a diagnosis of ADHD , both while taking and while not taking medication , and 13 healthy , unmedicated , age- and intelligence quotient-matched control subjects . RESULTS Stop-signal reaction time was significantly slower in unmedicated adults with ADHD relative to healthy control subjects , and this deficit was significantly ameliorated by medication . CONCLUSIONS Adult ADHD patients had a response inhibition profile similar to that produced by lesions to the right inferior frontal cortex , which was remedied by stimulant medication Nonmedical use of prescription-stimulant medication such as methylpheni date ( MPH ) has increased among college students over the past several years . Common motivations for use include enhancements in cognition and subjective arousal . As it is unclear whether stimulant medication exerts the same effect on healthy individuals as for those with attention-deficit/hyperactivity disorder , it is possible that many reported effects of prescription stimulants by healthy individuals may stem from placebo effects , which may be an important mechanism underlying initiation and maintenance of nonmedical use . This study examined whether placebo effects influence reports of subjective mood and cognitive performance among college students who endorsed several risk factors for prescription-stimulant misuse ( i.e. , low grade point average , fraternity/sorority involvement , binge drinking , cannabis use ) . Ninety-six subjects ( 60 % male ) completed cognitive tests and question naires assessing present mood state on two occasions . Forty-seven participants were r and omized to an experimental condition and orally ingested what they believed to be MPH , though actually placebo , on one visit and received no medication on the other visit . The control group received no medication on either visit . During the administration visit , experimental participants reported feeling significantly more high and stimulated compared with the nonadministration visit and to the control subjects . However , cognitive enhancement differences were not generally seen between visits or groups . This research demonstrates that placebo effects for prescription stimulants do influence subjective mood and may be implicated in nonmedical stimulant use . This knowledge may be useful in challenging prescription-stimulant-related expectancies to decrease the prevalence of use among college students How the brain monitors ongoing behavior for performance errors is a central question of cognitive neuroscience . Diminished awareness of performance errors limits the extent to which humans engage in corrective behavior and has been linked to loss of insight in a number of psychiatric syndromes ( e.g. , attention deficit hyperactivity disorder , drug addiction ) . These conditions share alterations in monoamine signaling that may influence the neural mechanisms underlying error processing , but our underst and ing of the neurochemical drivers of these processes is limited . We conducted a r and omized , double-blind , placebo-controlled , cross-over design of the influence of methylpheni date , atomoxetine , and citalopram on error awareness in 27 healthy participants . The error awareness task , a go/no-go response inhibition paradigm , was administered to assess the influence of monoaminergic agents on performance errors during fMRI data acquisition . A single dose of methylpheni date , but not atomoxetine or citalopram , significantly improved the ability of healthy volunteers to consciously detect performance errors . Furthermore , this behavioral effect was associated with a strengthening of activation differences in the dorsal anterior cingulate cortex and inferior parietal lobe during the methylpheni date condition for errors made with versus without awareness . Our results have implication s for the underst and ing of the neurochemical underpinnings of performance monitoring and for the pharmacological treatment of a range of disparate clinical conditions that are marked by poor awareness of errors Psychostimulants such as mixed amphetamine salts ( MAS , br and name Adderall ) are widely used for cognitive enhancement by healthy young people , yet laboratory research on effectiveness has yielded variable results . The present study assessed the effects of MAS in healthy young adults with an adequately powered double-blind cross-over placebo-controlled trial . We examined effects in 13 measures of cognitive ability including episodic memory , working memory , inhibitory control , convergent creativity , intelligence and scholastic achievement  , with the goals of determining ( 1 ) whether the drug is at least moderately enhancing ( Cohen 's d > = .5 ) to some or all cognitive abilities tested , ( 2 ) whether its effects on cognition are moderated by baseline ability or COMT genotype , and ( 3 ) whether it induces an illusory perception of cognitive enhancement . The results did not reveal enhancement of any cognitive abilities by MAS for participants in general . There was a suggestion of moderation of enhancement by baseline ability and COMT genotype in a minority of tasks , with MAS enhancing lower ability participants on word recall , embedded figures and Raven 's Progressive Matrices . Despite the lack of enhancement observed for most measures and most participants , participants nevertheless believed their performance was more enhanced by the active capsule than by placebo . We conclude that MAS has no more than small effects on cognition in healthy young adults , although users may perceive the drug as enhancing their cognition . This article is part of a Special Issue entitled ' Cognitive Enhancers ' OBJECTIVES To explore the illicit use of specific prescription stimulants among college students and add to our underst and ing of reasons ( motives ) and routes of administration associated with illicit use of these drugs . METHODS A r and om sample of 4580 college students self-administered a Web-based survey . The survey contained a variety of items pertaining to the illicit use of prescription stimulants . An extensive list of prescription stimulants was provided , and students were asked to select all the specific prescription stimulants that they had used illicitly . Items were also included to assess the motives and routes of administration associated with illicit use of prescription stimulants . RESULTS Lifetime and past-year prevalence rates for illicit use of prescription stimulants were 8.3 % ( 382 students ) and 5.9 % ( 269 students ) , respectively . Approximately three fourths ( 75.8 % ) of the 269 past-year illicit users of prescription stimulants reported using an amphetamine-dextroamphetamine combination agent ( e.g. , Adderall ) in the past year , and approximately one fourth ( 24.5 % ) reported using methylpheni date ( e.g. , Ritalin , Concerta , Meta date , Methylin ) . Past-year illicit use of prescription stimulants was more than 3 times more likely among Caucasians ( odds ratio [ OR ] 3.1 , 95 % confidence interval [ CI ] 1.5 - 6.6 ) and Hispanics ( OR 3.8 , 95 % CI 1.6 - 9.3 ) compared with African-Americans , and more than twice as likely among Caucasians ( OR 2.1 , 95 % CI 1.3 - 3.4 ) and Hispanics ( OR 2.6 , 95 % CI 1.4 - 5.1 ) compared with A 
    Output:
    