The brain functional magnetic resonance imaging characteristics induced by contact heat stimulations in normal adults / 中华神经科杂志

ABSTRACT

Objective Aδ and C fiber nociceptors can be excited when people received contact heat stimulation(CHS) and this excitation may be reflected by functional magnetic resonance imaging(fMRI).The aim of this study was to observe the different fMRI characteristics in CHS with distinct temperatures in healthy people and to explore the pain related functional network.Depending on the fMRI results,we can evaluate the values of CHS-fMRI during the research of brain functional connectivity.Methods Twenty-two healthy volunteers were recruited to this study.During the acquisition of fMRI,the right dorsal forearm received two different CHS in 41 and 51 degree respectively(41 ℃ CHS-fMRI group and 51 ℃ CHS-fMRI group),and two series of fMRI data were obtained for each subject.The brain activation was obtained by using one sample t test for the 41 ℃CHS-fMRI group and 51 ℃CHS-fMRI group separately.The difference between 41 ℃ CHS-fMRI group and 51 ℃ CHS-fMRI group was analyzed by paired-sample t-test.Result These activated brain areas in 41 ℃ CHS-fMRI group included bilateral superior temporal gyrus (STG),contralateral transverse temporal gyrus,contralateral amygdala,bilateral insula,bilateral inferior frontal gyrus (IFG),contralateral hippocampus,bilateral putamen,contralateral supramarginal,ipsilateral postcentral,ipsilateral inferior parietal lobule,ipsilateral middle temporal gyrus (MTG),bilateral cerebelum,bilateral middle cingulate cortex and bilateral posterior cingulate cortex.These activated brain areas in 51 ℃ CHS-fMRI group included bilateral STG,bilateral amygdala,contralateral hippocampus,bilateral thalamus,contralateral putamen,bilateral insula,bilateral IFG,bilateral cerebellum,contralateral postcentral,contralateral superior parietal lobule,bilateral MTG,bilateral precuneus,and contralateral cuneus.Compared with 41 ℃ CHS-fMRI group,the 51 ℃ CHS-fMRI group showed higher brain activation in bilateral cerebellum (right4.455,left3.891),ipsilateral precuneus (4.150),contralateral insula (3.530),contralateral IFG (3.530),and contralateral postcentral (3.530; t =2.83,P ＜ 0.01).Conclusions There are common brain activated areas and specific areas for each group,which suggested that existence of two central pathways activated by Aδ and C fiber which have different effects in perception of pain and have their brain network responsively.It may become one of the ideal pain stimulation methods with CHS-fMRI,which warrant worth further research.