***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: ABSTRACT Non – luminance-mediated changes in pupil diameter have been used since the first studies by Darwin in 1872 as indicators of clinical , cognitive , and arousal states . However , the relation between processes involved in motor control and changes in pupil diameter remains largely unknown . Twenty participants attempted to compensate  r and om walks of a cursor with a computer mouse to restrain its trajectory within a target circle while the authors recorded their pupil diameters . Two conditions allowed the authors to experimentally manipulate the motor and cognitive components of the task . First , the step size of the cursor 's r and om walk was either large or small leading to 2 task difficulties ( difficult or easy ) . Second , they instructed participants to imagine controlling the cursor by moving the mouse , but without actually moving it ( task modality : imagined movement or real movement condition ) . Task difficulty and modality allowed the authors to show that pupil diameters reflect processes involved in motor control and in the processing of feedback , respectively . Furthermore , the authors also demonstrate that motor learning can be quantified by pupil size . This noninvasive approach provides a promising method for investigating not only motor control , but also motor imagery , a research field of growing importance in sports and rehabilitation Cognitive processing efficiency requires both an ability to attend to task-relevant stimuli with quickness and accuracy , also while filtering distracting or task-irrelevant stimuli . This study investigated cognitive processing efficiency by using pupillary responses as an index of attentional allocation to relevant target and irrelevant masks on a visual backward masking task . The relationship between attentional allocation on this task and general cognitive ability on the scholastic aptitude test ( SAT ) was examined in college students ( n=67 ) . A principle components analysis of the pupillary response waveform isolated a late component that appeared to index the attentional dem and s associated with processing masks on the backward masking task . This pupillary response index of wasteful re source allocation to the mask accounted for significant variance in SAT scores over and above that accounted for by socio-economic status and target detection accuracy scores . Consistent with the neural efficiency hypothesis , individuals who allocated more re sources to processing irrelevant information performed more poorly on cognitive ability tests Classic theories of cognitive control conceptualized controlled processes as slow , strategic , and willful , with automatic processes being fast and effortless . The context -specific proportion compatibility ( CSPC ) effect , the reduction in the compatibility effect in a context ( e.g. , location ) associated with a high relative to low likelihood of conflict , challenged classic theories by demonstrating fast and flexible control that appears to operate outside of conscious awareness . Two theoretical questions yet to be addressed are whether the CSPC effect is accompanied by context -dependent variation in effort , and whether the exertion of effort depends on explicit awareness of context -specific task dem and s. To address these questions , pupil diameter was measured during a CSPC paradigm . Stimuli were r and omly presented in either a mostly compatible location or a mostly incompatible location . Replicating prior research , the CSPC effect was found . The novel finding was that pupil diameter was greater in the mostly incompatible location compared to the mostly compatible location , despite participants ’ lack of awareness of context -specific task dem and s. Additionally , this difference occurred regardless of trial type or a preceding switch in location . These patterns support the view that context ( location ) dictates selection of optimal attentional setting s in the CSPC paradigm , and varying levels of effort and performance accompany these setting s. Theoretically , these patterns imply that cognitive control may operate fast , flexibly , and outside of awareness , but not effortlessly Background Supporting 21st century health care and the practice of evidence -based medicine ( EBM ) requires ubiquitous access to clinical information and to knowledge-based re sources to answer clinical questions . Many questions go unanswered , however , due to lack of skills in formulating questions , crafting effective search strategies , and accessing data bases to identify best levels of evidence . Methods This r and omized trial was design ed as a pilot study to measure the relevancy of search results using three different interfaces for the PubMed search system . Two of the search interfaces utilized a specific framework called PICO , which was design ed to focus clinical questions and to prompt for publication type or type of question asked . The third interface was the st and ard PubMed interface readily available on the Web . Study subjects were recruited from interns and residents on an inpatient general medicine rotation at an academic medical center in the US . Thirty-one subjects were r and omized to one of the three interfaces , given 3 clinical questions , and asked to search PubMed for a set of relevant articles that would provide an answer for each question . The success of the search results was determined by a precision score , which compared the number of relevant or gold st and ard articles retrieved in a result set to the total number of articles retrieved in that set . Results Participants using the PICO templates ( Protocol A or Protocol B ) had higher precision scores for each question than the participants who used Protocol C , the st and ard PubMed Web interface . ( Question 1 : A = 35 % , B = 28 % , C = 20 % ; Question 2 : A = 5 % , B = 6 % , C = 4 % ; Question 3 : A = 1 % , B = 0 % , C = 0 % ) 95 % confidence intervals were calculated for the precision for each question using a lower boundary of zero . However , the 95 % confidence limits were overlapping , suggesting no statistical difference between the groups . Conclusion Due to the small number of search es for each arm , this pilot study could not demonstrate a statistically significant difference between the search protocol s. However there was a trend towards higher precision that needs to be investigated in a larger study to determine if PICO can improve the relevancy of search results The attentional learning theory of Pearce and Hall ( ) predicts more attention to uncertain cues that have caused a high prediction error in the past . We examined how the cue-elicited pupil dilation during associative learning was linked to such error-driven attentional processes . In three experiments , participants were trained to acquire associations between different cues and their appetitive ( Experiment 1 ) , motor ( Experiment 2 ) , or aversive ( Experiment 3 ) outcomes . All experiments were design ed to examine differences in the processing of continuously reinforced cues ( consistently followed by the outcome ) versus partially reinforced , uncertain cues ( r and omly followed by the outcome ) . We measured the pupil dilation elicited by the cues in anticipation of the outcome and analyzed how this conditioned pupil response changed over the course of learning . In all experiments , changes in pupil size complied with the same basic pattern : During early learning , consistently reinforced cues elicited greater pupil dilation than uncertain , r and omly reinforced cues , but this effect gradually reversed to yield a greater pupil dilation for uncertain cues toward the end of learning . The pattern of data accords with the changes in prediction error and error-driven attention formalized by the Pearce-Hall theory The size of the human pupil increases as a function of mental effort . However , this response is slow , and therefore its use is thought to be limited to measurements of slow tasks or tasks in which meaningful events are temporally well separated . Here we show that high-temporal-resolution tracking of attention and cognitive processes can be obtained from the slow pupillary response . Using automated dilation deconvolution , we isolated and tracked the dynamics of attention in a fast-paced temporal attention task , allowing us to uncover the amount of mental activity that is critical for conscious perception of relevant stimuli . We thus found evidence for specific temporal expectancy effects in attention that have eluded detection using neuroimaging methods such as EEG . Combining this approach with other neuroimaging techniques can open many research opportunities to study the temporal dynamics of the mind ’s inner eye in great detail The contributions of separate sympathetic and parasympathetic pathways to pupillary dilation during a sustained processing task were studied through environmental and pharmacological manipulations . In Experiment 1 , 22 healthy volunteers ( 11 female ) performed a serial Subtract 7 task while pupil diameter was recorded both during moderate room light and in darkness . In a control for verbalization , subjects performed an easier Add 1 task . In all conditions , pupil diameter increased significantly during the response period as compared to a pre-verbalization baseline period . Pupillary dilation was increased for the difficult task , and further increase in dilation was associated with recording in light . This suggests a major differential contribution to task difficulty mediated through inhibition of the parasympathetic pathway . In Experiment 2 , a subgroup of 12 volunteers ( seven female ) repeated all conditions at three additional sessions in which one eye was instilled with tropicamide ( to block the parasympathetic sphincter muscle ) , dapiprazole ( to block the sympathetic dilator muscle ) or placebo . All pharmacological conditions result ed in overall dilation during task performance . Differential performance similar to the placebo condition was seen only in the dapiprazole condition , when parasympathetic activation was intact . The findings suggest that sustained performance during a difficult task is modulated by cortical inhibition of the parasympathetic pathway at the oculomotor nucleus . Moreover , modulation of both ambient light intensity and pharmacological blockade of the final pupillary musculature were observed to provide converging approaches for quantifying the activity of identifiable central autonomic pathways The psychological arrow of time refers to our experience of the forward temporal progression of all natural processes . To investigate whether and how time 's arrow is mentally coded in individual everyday events , a relatedness judgment task was used . The items each consisted of a verb ( probe ) and an adjective or participle ( target ) . The temporal orientation between probe and target was varied either corresponding to the chronological orientation ( e.g. , shrinking-small ) or corresponding to the reverse orientation ( e.g. , shrinking-large ) . Reaction times , error rates , and pupillary responses were recorded . Chronological items were processed faster than reverse items . These findings suggest that time 's arrow is mentally coded in single everyday events . Pupil dilation and results of principal component analyses suggest top-down influences in the processing of temporally related items Recent studies have shown that prior knowledge about where , when , and who is going to talk improves speech intelligibility . How related attentional processes affect cognitive processing load has not been investigated yet . In the current study , three experiments investigated how the pupil dilation response is affected by prior knowledge of target speech location , target speech onset , and who is going to talk . A total of 56 young adults with normal hearing participated . They had to reproduce a target sentence presented to one ear while ignoring a distracting sentence simultaneously presented to the other ear . The two sentences were independently masked by fluctuating noise .  Target location ( left or right ear ) , speech onset , and talker variability were manipulated in separate experiments by keeping these features either fixed during an entire block or r and omized over trials . Pupil responses were recorded during listening and performance was scored after recall . The results showed an improvement in performance when the location of the target speech was fixed instead of r and omized . Additionally , location uncertainty increased the pupil dilation response , which suggests that prior knowledge of location reduces cognitive load . Interestingly , the observed pupil responses for each condition were consistent with subjective reports of listening effort . We conclude that communicating in a dynamic environment like a cocktail party ( where participants in competing conversations move unpredictably ) requires substantial listening effort because of the dem and s placed on attentional processes The effect of memory load on the cognitive pupillary response among 16 young adults and 16 older adults was investigated . Mean pupil dilation and reaction time were measured during a Sternberg memory- search task , which involved six levels of memory load . A classic interaction pattern was obtained in which the reaction times of the elderly participants increased more as a function of memory load than the reaction times of the young participants . In the encoding phase of the experiment , mean dilation increased with memory load . No age differences were observed here . In the search phase of the experiment , however , mean pupil dilation was considerably greater in the young than in the elderly participants . Moreover , mean dilation of the older participants was not sensitive to memory load , whereas mean dilation increased as a function of memory load in the young participants . The results suggest that the usefulness of the pupillary response as a correlate of subtle fluctuations in memory load diminishes with old age The influence of levels of abstract ion in picture-word matching was examined . The items each consisted of one picture and three successively presented words . Hierarchies with words for superordinate , basic , and subordinate level concepts were used ( e.g. , plant , flower , rose ) . The picture-word condition ( congruent , incongruent ) , the word position ( first , second , third ) , and the level of categorization ( subordinate , basic , superordinate ) were manipulated . Reaction times , error rates , and pupillary responses were recorded . Pupillary responses coincided with behavioral data . In general , there was an advantage for subordinate and basic level processing compared to superordinate level processing . However , switches to words for superordinate concepts were most facilitated . These findings support a two-step account of picture-word matching . First , the picture is categorized according to its concrete features . Second , amodal features are processed Previous studies have related changes in attentional load to pupil size modulations . However , studies relating changes in attentional load and task experience on a finer scale to pupil size modulations are scarce . Here , we investigated how these changes affect pupil sizes . To manipulate attentional load , participants covertly tracked between zero and five objects among several r and omly moving objects on a computer screen . To investigate effects of task experience , the experiment was conducted on three consecutive days . We found that pupil sizes increased with each increment in attentional load . Across days , we found systematic pupil size reductions . We compared the model fit for predicting pupil size modulations using attentional load , task experience , and task performance as predictors . We found that a model which included attentional load and task experience as predictors had the best model fit while adding performance as a predictor to this model reduced the overall model fit . Overall , results suggest that pupillometry provides a viable metric for precisely assessing attentional load and task experience in visuospatial tasks The aim of the present study was to evaluate whether the anticipatory pupillary dilation response is a useful indicator for the examination of complex differential conditioning problems like patterning . A human fear conditioning procedure with six groups ( n=20 each ) was used to examine conditioned stimulus ( CS ) processing when a compound stimulus was reinforced , but not its elements ( positive patterning ) or when the elements were reinforced , but not the compound ( negative patterning ) , as well as modifications in which the compound was replaced by either a new compound or by a new element . We found evidence for conditioning within 2 s after CS onset . Group differences 
    Output:
    
Conclusions Pupillary dilatation occurs with many kinds of mental or emotional processes , following sympathetic activation or parasympathetic inhibition .
Conversely , pupillary constriction may occur with anticipation of a bright stimulus ( even in its absence ) and relies on a parasympathetic activation .
All these reactions are controlled by subcortical and cortical structures that are directly or indirectly connected to the brainstem pupillary innervation system