***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: The experience of pain arises from both physiological and psychological factors , including one 's beliefs and expectations . Thus , placebo treatments that have no intrinsic pharmacological effects may produce analgesia by altering expectations . However , controversy exists regarding whether placebos alter sensory pain transmission , pain affect , or simply produce compliance with the suggestions of investigators . In two functional magnetic resonance imaging ( fMRI ) experiments , we found that placebo analgesia was related to decreased brain activity in pain-sensitive brain regions , including the thalamus , insula , and anterior cingulate cortex , and was associated with increased activity during anticipation of pain in the prefrontal cortex , providing evidence that placebos alter the experience of pain Abstract Although individual differences in fear and anxiety modulate the pain response and may even cause more suffering than the initiating physical stimulus , little is known about the neural systems mediating this relationship . The present study provided the first examination of the neural correlates of individual differences in the tendency to ( 1 ) feel anxious about the potentially negative implication s of physical sensations , as measured by the anxiety sensitivity index ( ASI ) , and ( 2 ) fear various types of physical pain , as indexed by the fear of pain question naire ( FPQ ) . In separate sessions , participants completed these question naires and experienced alternating blocks of noxious thermal stimulation ( 45–50 ° C ) and neutral thermal stimulation ( 38 ° C ) during the collection of whole‐brain fMRI data . Regression analyses demonstrated that during the experience of pain , ASI scores predicted activation of a medial prefrontal region associated with self‐focused attention , whereas FPQ scores predicted activation of a ventral lateral frontal region associated with response regulation and anterior and posterior cingulate regions associated with monitoring and evaluation of affective responses . These functional relationships can not be wholly explained by generalized anxiety ( indexed by STAI‐T scores ) , which did not significantly correlate with activation of any regions . The present findings may help clarify both the impact of individual differences in emotion on the neural correlates of pain , and the roles in anxiety , fear , and pain processing played by medial and orbitofrontal systems The endogenous opioid system is involved in stress responses , in the regulation of the experience of pain , and in the action of analgesic opiate drugs . We examined the function of the opioid system and μ-opioid receptors in the brains of healthy human subjects undergoing sustained pain .  Sustained pain induced the regional release of endogenous opioids interacting with μ-opioid receptors in a number of cortical and subcortical brain regions . The activation of the μ-opioid receptor system was associated with reductions in the sensory and affective ratings of the pain experience , with distinct neuroanatomical involvements . These data demonstrate the central role of the μ-opioid receptors and their endogenous lig and s in the regulation of sensory and affective components of the pain experience OBJECTIVE : The lack of a suitable disease-specific , health-related quality of life instrument for dyspepsia prompted the development of the Nepean Dyspepsia Index ( NDI ) . The utility of the NDI in functional dyspepsia is unknown . We aim ed to assess the validity of this new quality of life instrument for the first time in United States patients with documented functional dyspepsia . METHODS : The long form of the NDI contains a symptom index and 42 items design ed to measure impairment of subjects ’ ability to engage in and to enjoy relevant aspects of their life because of dyspepsia , as well as a ranking of the individual importance of each aspect . Patients ( n = 101 , mean age 51 yr , 62 % female ) who had a history of functional dyspepsia for ≥1 month and a negative endoscopy within the prior 1 yr were followed for 14 days . Patients completed the NDI and the vali date d Speilberger State-Trait Anxiety Inventory , Beck Depression Inventory , Short Form-36 , and a global assessment of symptoms and quality of life at baseline and 14 days later ; the NDI was also retested at 48 h and 2 wk . RESULTS : Five clinical ly relevant factors ( subscales ) , namely , tension/sleep , interference , eating/drinking , knowledge/control , and work/ study were identified by factor analysis , after incorporating individual importance ratings ( 25 items total ) . All subscales had excellent face validity and internal consistency ( Chronbach 's α , all > 0.85 ) . Reliability was also excellent ( intraclass correlations all > 0.84 ) . There were modest typically negative correlations between a number of the NDI subscales and the Short Form-36 , anxiety , and depression , indicating that the NDI is disease-specific and supporting its validity . Changes in NDI scales correlated moderately with global assessment of change ( total score r = −0.49 ) , indicating initial responsiveness . CONCLUSIONS : The Nepean Dyspepsia Index is a valid , disease-specific index for functional dyspepsia , measuring symptoms and health-related quality of life BACKGROUND & AIMS Hypersensitivity to proximal gastric distention as a result of abnormal central nervous system processing of visceral stimuli is a possible pathophysiologic mechanism in functional dyspepsia ( FD ) . Increasing evidence suggests involvement of both lateral and medial pain systems in normal visceral sensitivity and aberrant brain activation patterns in visceral hypersensitivity . We hypothesized that there is involvement of aberrant brain activation in FD with hypersensitivity to gastric distention . Our aim was to investigate regional cerebral blood flow during painful proximal gastric distention in hypersensitive FD . METHODS Brain (15)O-water positron emission tomography was performed in 13 FD patients with symptoms of gastric hypersensitivity during 3 conditions : no distention , sham distention , and isobaric distention to unpleasant or painful sensation .  Pain , discomfort , nausea , and bloating during maximal distention were rated on visual analogue scales . Data were analyzed using statistical parametric mapping . RESULTS The threshold for painful distention was 6.6 + /- 3.8 mm Hg greater than the minimal distending pressure . At the corrected P level of less than .05 , subtraction analysis ( painful distention - no distention ) showed activations in bilateral gyrus pre central is , bilateral gyrus frontalis inferior , bilateral gyrus frontalis medialis , bilateral gyrus temporalis superior , bilateral cerebellar hemisphere , and left gyrus temporalis inferior . Sham distention minus no distention showed no activations . CONCLUSIONS Similar to healthy volunteers , proximal stomach distention in FD activates components of the lateral pain system and bilateral frontal inferior gyri , putatively involved in regulation of hunger and satiety . In hypersensitive FD , these activations occur at significantly lower distention pressures . In contrast to findings in normosensitivity , none of the components of the medial pain system were significantly activated & NA ; Irritable bowel syndrome ( IBS ) is one of the most common gastrointestinal illnesses and is characterized by altered visceral perception . Previous studies in IBS have failed to demonstrate altered somatic or cutaneous perception . The aims of the study were to determine whether IBS patients have visceral hypersensitivity and cutaneous heat‐induced hyperalgesia restricted to lumbosacral dermatomes , consistent with a localized segmental mechanism . Twelve patients ( ten women , two men ) with IBS and 17 control subjects ( 13 women , four men ) rated pain intensity and unpleasantness to distension of the rectum ( 35 , 55 mmHg ) and thermal stimulation ( 45 , 47 ° C ) of the h and and foot . Patients with IBS demonstrated cutaneous allodynia/hyperalgesia to thermal pain applied to the h and and foot . The cutaneous hyperalgesia was pronounced in the lower extremity yet present in the upper extremity to a lesser extent . Psychological testing revealed the IBS patients report more state anxiety and a greater number of somatic symptoms that significantly correlated with most of the pain measures . However , they did not differ from controls on several personality trait measures . These results suggest that patients with IBS have visceral hyperalgesia and cutaneous hyperalgesia that is distributed over a considerable rostral‐caudal distance yet optimally expressed in lumbosacral dermatomes . This distribution is consistent with patterns of spinal hyperexcitability observed in experimentally induced persistent pain conditions OBJECTIVES : Acupuncture is a commonly used therapy for treating functional dyspepsia ( FD ) , although the mechanism remains unclear . The objectives of this study were to investigate the differences in cerebral glycometabolism changes evoked by acupuncture and sham acupuncture and to explore the possible correlations between brain responses and clinical efficacy . METHODS : In all , 72 FD patients were r and omly assigned to receive either acupuncture or sham acupuncture treatment for 4 weeks . Ten patients in each group were r and omly selected for fluorine-18 fluorodeoxyglucose positron emission tomography computed tomography scans to detect cerebral glycometabolism changes . The Nepean Dyspepsia Index ( NDI ) and Symptom Index of Dyspepsia ( SID ) were used to evaluate the therapeutic effect . RESULTS : ( i ) The clinical data showed that after treatment the decrease in SID score in the acupuncture group was significantly greater than that in the sham acupuncture group ( P<0.05 ) . The increase in NDI score between the two groups did not differ ( P>0.05 ) , and only the improvement in NDI score in the acupuncture group was clinical ly significant . ( ii ) The neuroimaging data indicated that after treatment the acupuncture group showed extensive deactivation in cerebral activities compared with the sham acupuncture group . In the acupuncture group , the deactivations of the brainstem , anterior cingulate cortex ( ACC ) , insula , thalamus , and hypothalamus were nearly all related to the decrease in SID score and the increase in NDI score ( P<0.05 , corrected ) . In the sham acupuncture group , the deactivations of the brainstem and thalamus tended to be associated with the increase in NDI score ( P<0.1 , corrected ) . CONCLUSIONS : Acupuncture and sham acupuncture have relatively different clinical efficacy and brain responses . Acupuncture treatment more significantly improves the symptoms and quality of life of FD patients . The more remarkable modulation on the homeostatic afferent network , including the insula , ACC , and hypothalamus , might be the specific mechanism of acupuncture It has been suggested that placebo analgesia involves both higher order cognitive networks and endogenous opioid systems . The rostral anterior cingulate cortex ( rACC ) and the brainstem are implicated in opioid analgesia , suggesting a similar role for these structures in placebo analgesia . Using positron emission tomography , we confirmed that both opioid and placebo analgesia are associated with increased activity in the rACC . We also observed a covariation between the activity in the rACC and the brainstem during both opioid and placebo analgesia , but not during the pain-only condition . These findings indicate a related neural mechanism in placebo and opioid analgesia & NA ; Visceral pain/discomfort is the cardinal complaints and treatment targets for functional gastrointestinal disorders ( FGID ) . However , effective treatment for such pain is limited and often associated with high placebo effects . The mechanisms of placebo effects in visceral pain are unclear . We used functional neuroimaging to study the central representations of the placebo effect and its anticipation during esophageal pain in healthy adults . Fourteen subjects were enrolled .  Pain extent , psychophysical inventories [ Pain Catastrophizing Scale ( PAS ) , visual analogue scale ( VAS ) and short‐form McGill question naire ]  , and  brain activity upon placebo intervention and upon anticipation were assessed in response to esophageal balloon distension . Large reductions of pain extent , VAS rating , short‐form McGill question naire scores , and brain activity in the visceral pain matrix [ thalamus , somatosensory cortices , insula , prefrontal cortex ( PFC ) , anterior cingulate cortex ] were observed upon placebo treatment . The aforementioned brain areas and the bilateral amygdala were significantly correlated with decreased pain extent and VAS in response to placebo . The ventral lateral PFC ( VLPFC ) was associated with increased activity during anticipation of visceral pain . PAS can not predict the placebo effect in visceral pain . In conclusion , pronounced placebo analgesia was coupled with prominent changes of brain activity in visceral pain matrix , which are thus likely involved in high placebo efficacy during the treatment of visceral pain in FGID . VLPFC activation during the anticipation of placebo analgesia suggests top‐down control in the modulation of pain experience 
    Output:
    
Changes were reported in several brain areas in FD patients including the frontal cortex , somatosensory cortex , insula , anterior cingulate cortex , thalamus , hippocampus , and amygdala .
These brain activity changes were associated with visceral hypersensitivity , dyspeptic symptoms , poorer quality of life , anxiety , and depression .
The results show that FD is associated with functional abnormalities in sensory and pain modulation , emotion , saliency , and homeostatic processing regions .