ABSTRACT
Objective To investigate the effects of different doses of fentanyl on pain-activated brain areas as demonstrated by functional magnetic resonance imaging (fMRI) at 3.0 T.Methods Twenty healthy right-handed male volunteers aged 20-40 yr were randomly divided into 2 groups ( n =10 each); group F1 (fentanyl 1.0 μg/kg) and group F2 (fentanyl 1.5 μg/kg).Mechanical stimulation with von Frey filaments (vFFs,300 g) was delivered to left sole.The intensity of pain was assessed by VAS scores.fMRI was performed before and after fentanyl administration and the changes in the brain areas activated by pain were recorded.Results In group F1 ipsilateral (left) cingulate gyrus was activated after a bolus of fentanyl 1.0 μg/kg under stimulation with vFFs 300 g,while in group F2 bilateral cingulate gyrus and contralateral (right) insula were activated under vFFs stimulation after fentanyl 1.5 μg/kg.Conclusion Cingulate gyrus and insula may be the target brain areas of fentanyl analgesia.
ABSTRACT
Objective To locate the brain areas in which pain was induced by mechanical noxious stimulation by using functional magnetic resonance imaging.Methods Twenty healthy male volunteers,aged 20-40 yr,with body mass index of 18-25 kg/m2,were involved in this study.The volunteers were stimulated with 300 g von Frey filaments.Functional magnetic resonance imaging examinations were performed 1 week later.The monitoring data were collected during the scanning.The images were analyzed with SPM2 software.Results Bain areas in which pain was induced by mechanical noxious stimulation with 300 g yon Frey filaments were bilateral anterior cingulate gyrus,right contralateral insula and bilateral primary somatic sensory cortex.Conclusion The brain areas in which pain is induced by mechanical noxious stimulation include bilateral anterior cingulate gyrus,right contralateral insula and bilateral primary somatic sensory cortex.