introduction: prior studies comparing hemodynamic response function (hrf) in the young and elderly adults based on fmri data have reported inconsistent findings for brain vision and motor regions in healthy aging. it is shown that the averaging method employed in all previous works has caused this inconsistency. the averaging is so sensitive to outliers and noise. however, fmri data are obscure...

introduction: a fixed hemodynamic response function (hrf) is commonly used for functional magnetic resonance imaging (fmri) analysis. however, hrf may vary from region to region and subject to subject. we investigated the effect of locally estimated hrf (in functionally homogenous parcels) on activation detection sensitivity in a heroin cue reactivity study. methods: we proposed a novel explora...

background : we aimed to compare hemodynamic and endocrine alterations caused by stress response due to proseal laryngeal mask airway and endotracheal tube usage in laparoscopic cholecystectomy. methods : sixty-three asa i-ii patients scheduled for elective laparoscopic cholecystectomy were included in the study. patients were randomly allocated into two groups of endotracheal tube and proseal ...

background: etomidate and propofol are common anesthetic agents. previous studies say that etomidate can be used in patients with limited hemodynamic reserve and propofol can lead to more hemodynamic instabilities. th is study was performed to explore the cardiovascular response during the induction of anesthesia with etomidate or for comparison, propofol in elective orthopedic surgeries. mater...

background: although a variety of methods have been suggested to reduce stress, anxiety and pain intensity due to spinal needle skin puncture, their adverse effects restrict theirs widespread administration. in this study we evaluated the effects of oral tizanidine on the reduction of pain caused by spinal needle puncture and hemodynamic responses. methods : in this double blind randomized clin...