***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 evoked response to repeated auditory stimuli generally decreases in amplitude , a phenomenon that demonstrates the activity of sensory gating mechanisms in the central nervous system ( CNS ) . Gating of the P50 wave of the auditory evoked response shows such behavior in normals , but not in schizophrenic or manic subjects . In mania , diminished gating of the auditory evoked response is correlated with elevated levels of noradrenergic metabolites . In animals , yohimbine , a presynaptic α-2 antagonist , increases noradrenergic neuronal transmission in the CNS and diminished gating of the auditory evoked response . The aim of this experiment was to test whether yohimbine causes diminished auditory sensory gating in normal human controls . Seven normal subjects with normal P50 auditory gating  were treated either with 0.4 mg/kg of oral yohimbine on one day or placebo on a different day . Each subject acted as his own control . Yohimbine , but not placebo , caused a significant but transient decrease in P50 auditory gating in these subjects . Thus , increasing CNS noradrenergic neuronal transmission in normal controls can cause a transient impairment in auditory sensory gating BACKGROUND Stressful life events have long been suspected to contribute to multiple sclerosis ( MS ) disease activity . The few studies examining the relationship between stressful events and neuroimaging markers have been small and inconsistent . This study examined whether different types of stressful events and perceived stress could predict the development of brain lesions . METHOD This was a secondary analysis of 121 patients with MS followed for 48 weeks during a r and omized controlled trial comparing stress management therapy for MS ( SMT-MS ) to a waitlist control ( WLC ) .  Patients underwent magnetic resonance imaging ( MRI ) scans every 8 weeks . Every month , patients completed an interview measure assessing stressful life events  and  self-report measures of perceived stress , anxiety and depressive symptoms , which were used to predict the presence of gadolinium-enhancing ( Gd+ ) and T2 lesions on MRI scans 29 - 62 days later . Participants classified stressful events as positive or negative . Negative events were considered ' major ' if they involved physical threat or threat to the patient 's family structure , and ' moderate ' otherwise . RESULTS Positive stressful events predicted decreased risk for subsequent Gd+ lesions in the control group [ odds ratio ( OR ) 0.53 for each additional positive stressful event , 95 % confidence interval ( CI ) 0.30 - 0.91 ] and less risk for new or enlarging T2 lesions regardless of group assignment ( OR 0.74 , 95 % CI 0.55 - 0.99 ) . Across groups , major negative stressful events predicted Gd+ lesions ( OR 1.77 , 95 % CI 1.18 - 2.64 ) and new or enlarging T2 lesions ( OR 1.57 , 95 % CI 1.11 - 2.23 ) whereas moderate negative stressful events , perceived stress , anxiety and depressive symptoms did not . CONCLUSIONS Major negative stressful events predict increased risk for Gd+ and T2 lesions whereas positive stressful events predict decreased risk This study aim ed to evaluate neuroendocrine responses and changes in perceptual asymmetry following an induced negative affect . Cortisol increasing in response to negative affect has been reported , while current brain models of emotion processing link negative affect to the right hemisphere . In this study , the Velten Mood Induction Procedure was used to generate neutral or negative affect in 44 healthy subjects . The PANAS scales were used to assess self-reported mood . A consonant-vowel dichotic listening ( DL ) test was applied after the neutral and negative affect inductions , and levels of salivary cortisol were determined by radioimmunoassay . For the negative affect condition , and congruent with the hypothesis tested , PANAS positive scores diminished ( p<0.001 ) and PANAS negative scores increased ( p<0.001 ) , yielding an inverse correlation between them . A significant increase in cortisol levels was also seen ( p<0.04 ) . When taking cortisol reactivity into account , PANAS negative scores were higher for high-than for low-cortisol responders ( p<0.02 ) . Regarding DL , an increase in left ear items ( p<0.04 ) and a decrease in right ear items ( p<0.03 ) reported for those subjects who obtained a right ear advantage in the neutral condition . An explanation in terms of Kinsbourne 's model for attentional-activation influences on DL is postulated and implication s for the issue of affective illness are also discussed Electrophysiological studies have revealed a pre-attentive change-detection system in the auditory modality . This system emits a signal termed the mismatch negativity ( MMN ) when any detectable change in a regular pattern of auditory stimulation occurs . The precise intracranial sources underlying MMN generation , and in particular whether these vary as a function of the acoustic feature that changes , is a matter of some debate . Using functional magnetic resonance imaging , we show that anatomically distinct networks of auditory cortices are activated as a function of the deviating acoustic feature -- in this case , tone frequency and tone duration --strongly supporting the hypothesis that MMN generators in auditory cortex are feature dependent . We also detail regions of the frontal and parietal cortices activated by change-detection processes . These regions also show feature dependence and we hypothesize that they reflect recruitment of attention-switching mechanisms The cold pressor test ( CPT ) is an empirically vali date d test commonly used in research on stress , pain and cardiovascular reactivity . Surprisingly , the equivalent test with water heated to noxious temperatures ( hot water immersion test , HIT ) has not been thoroughly investigated . The aim of the present study was to characterize the physiological effects and psychophysics of both tests and to analyze whether the autonomic responses are mainly induced by baroreflexes or a consequence of the pain experience itself . The study consisted of a single session including one CPT ( 4 ± 0.2 ° C ) and one HIT ( 47 ± 0.5 ° C ; cut‐off point 5 min ) trial performed on 30 healthy drug free volunteers aged 19–57 ( median 24 ) yrs . The sequence of both trials was alternated and participants were r and omly assigned to sequence order and parallelized with respect to gender . Physiological parameters ( cardiovascular , respiratory and electrodermal activity ) and subjective pain intensity were continuously monitored . In addition , pain detection and tolerance thresholds as well as pain unpleasantness were assessed . Both tests were comparable with regard to the time course and intensity of subjective pain . However , a significantly higher increase of blood pressure could be observed during the CPT when compared to the HIT . The HIT appears less confounded with thermoregulatory baroreflex activity and therefore seems to be a more appropriate model for tonic pain Data from five independent studies were reanalyzed in order to investigate the impact of age and gender on HPA axis responses to an acute psychosocial laboratory stress task . The total sample consisted of 102 healthy subjects with 30 older adults ( mean age : 67.3 y ) , 41 young adults ( mean age : 23.5 y ) , and 31 children ( mean age : 12.1 y ) . All participants were exposed to the Trier Social Stress Test ( TSST ) . The stress protocol caused highly significant ACTH and total plasma cortisol responses in older and younger male and female adults ( all p<0.0001 ) as well as salivary free cortisol responses in all six age and gender groups ( all p<0.0001 ) . Three-way ANOVAs for repeated measurement were applied to investigate the impact of age and gender on ACTH and cortisol responses . Results showed that the ACTH response to stress was higher in younger adults compared to older adults ( main effect : p=0.009 , interaction : p=0.06 ) . Post hoc analyses revealed that there was no age effect in the subgroup of women ( p = n.s . ) , while younger men had higher ACTH responses compared to older men ( p=0.01 ) . For total plasma cortisol , ANOVA results showed that the pattern of reactivity did not differ between age and gender groups ( all interactional effects p = n.s . ) , although older females had hightened overall cortisol levels compared to the other groups , as proofed in post hoc analyses ( all p<0.05 ) . For free salivary cortisol , a significant main effect of gender ( p=0.05 ) and an almost significant three-way-interaction ( p=0.09 ) emerged . Post hoc analyses showed an elevated overall free salivary cortisol response in elderly men compared to elderly women ( p=0.006 ) , while no gender differences emerged in neither young adults nor children ( both p = n.s . ) . In sum , the stressor induced significant HPA axis responses in all age and gender groups . The observed ACTH response patterns in young and elderly adults may suggest that a heightened hypothalamic drive in young men decreases with age , result ing in similar ACTH responses in elderly men and women . Alternative interpretations are also discussed . The data also supports the idea of a greater adrenal cortex sensitivity to ACTH signals in young females . Free salivary cortisol responses were elevated in elderly men compared to elderly women , an effect which can not be explained by gender differences in perceived stress responses to the TSST . It can be speculated if corticosteroid binding globulin ( CBG ) and /or sex steroids are important modulators of these effects White and Yee ( 1997 ) found that normal suppression of the P50 component of the event-related potential was disrupted during a paired-click paradigm when nonpsychiatric subjects performed mental arithmetic ( MA ) problems aloud , concurrently with the presentation of auditory stimuli . In fact , the degree of disruption reflected in the P50 suppression ratio fell within the range that is typically observed in schizophrenia patients . The present study was conducted to clarify the processes that might underlie the apparent disruption of P50 suppression during performance of an oral MA task .  Participants completed a series of tasks design ed to examine the impact of competing cognitive activity , competing auditory stimulation , muscle activity , and acute psychological stress on P50 amplitude and P50 suppression . Results suggested that psychological stress and heightened facial muscle activity may exert modulatory effects on P50 suppression Inhibitory gating of response to repeated stimuli is demonstrated by several event-related potentials , including the auditory P50 wave . The present study examined the effects of variation in sound intensity on this phenomenon in schizophrenics and normal subjects .  Paired clicks , 500 ms apart , were presented 50 dB above threshold to 10 normal subjects and 10 schizophrenics . The normal subjects demonstrated significantly more decrement of response to the second stimulus than did the schizophrenics . When the sounds were noticeably louder(70 dB above threshold ) , no such difference was observed . Rather , both groups had similarly diminished gating of response . A significant difference between schizophrenics and normal subjects was also observed when the sounds were 30 dB above threshold , but the difference was smaller than that at 50 dB. At any stimulus intensity , concomitant eye movements led to loss of gating of P50 in the normal subjects This study examined stress cortisol responses and cognitive performance . We initially measured cortisol responses of 40 right-h and ed healthy male volunteers to counterbalanced mental arithmetic and public speaking stressors . We then examined the relationship between cortisol reactivity and  dichotic listening and mental arithmetic performance . High cortisol responders made more errors and completed fewer mental arithmetic items than low reactors . On dichotic listening , high responders tended toward better performance in all conditions and to both ears . High responders showed better performance to the right ear in the forced right than in the nonforced condition , whereas no difference between these conditions was found in low responders . High cortisol responders may have an increased focus on sensory stimuli and a decreased allocation of re sources to working memory tasks UNLABELLED As a method of experimental pain induction , the cold pressor test is thought to mimic the effects of chronic conditions effectively . A survey of previous studies using the cold pressor , however , revealed a lack of st and ardization and control of water temperature , question ing comparability and reliability . This study reports the influence of temperature on pain tolerance and intensity by using a commercially available circulating water bath . Twenty-six participants ( 12 men , 14 women ) underwent 4 cold pressor trials with temperature order counterbalanced across 1 degrees C , 3 degrees C , 5 degrees C , and 7 degrees C , temperatures representative of the range used in previous literature . After each cold immersion participants rated pain intensity on a visual analogue scale and the McGill Pain Question naire . Tolerance times were recorded for each trial . Significant main effects of temperature were found for tolerance time , with higher temperatures result ing in longer times , and pain intensity , with lower temperatures result ing in higher intensities . Gender differences were found , with men tolerating the stimulus for significantly longer than women . It was concluded that small differences in water temperature have a significant effect on pain intensity and tolerance time . The use of cold pressor equipment that ensures a precise constant temperature of circulating water is necessary to ensure comparable and reliable results . PERSPECTIVE The cold pressor method of experimental pain induction has been widely used in the evaluation of psychological and physiological pain treatments . This article highlights the need for clear method ologic guidelines for the technique and demonstrates that very minor changes in experimental protocol can produce significant differences The reproducibility of the cold pressor test was studied in healthy subjects . A non-invasive method was utilized for estimating beat-to-beat arterial blood pressure ( BP ) and heart rate ( HR ) . The study population of 17 healthy volunteers consisted of two groups . In the first group ( Group 1 , n=11 ) , a 1-min test was performed three times during the same day . In the second group ( Group 2 , n=6 ) , a 2-min test was repeated at the same time of the day on three consecutive days . In both groups , the test response was defined as the 46- to 6 
    Output:
    
The results revealed the adverse effects of acute physical and psychological stresses on auditory processing .