纯音刺激前后正常人听皮层代谢变化1HMRS研究

Biochemical changes in auditory cortex in response to pure tone stimulation： a 1H-MRS study

目的利用质子磁共振波谱(protonmagnetic resonance spectroscopy,1H-MRS)技术研究纯音刺激前后正常人大脑听皮层代谢变化。方法 10例健康受试者双侧听皮层在纯音刺激前后接受两次多体素磁共振波谱检查。刺激声为声强90dB、频率1000Hz的正弦波纯音脉冲,左耳给声。观察双侧听皮层N-乙酰天门冬氨酸(N-aceytlaspartate,NAA)、肌酸(creatine,Cr)、胆碱(choline,Cho)、谷氨酰胺和谷氨酸(glutamate/glutamine,Glx)等代谢物的波峰变化并进行半定量分析。结果左耳纯音刺激后双侧听皮层NAA/(Cho+Cr)、Glx/(Cho+Cr)比值均增高,Cho/Cr比值降低,NAA/(Cho+Cr)、Glx/(Cho+Cr)、Cho/Cr刺激前后差异在右侧听皮层均具有统计学意义(P<0.05),但在左侧听皮层差异无统计学意义(P>0.05)。结论 1HMRS可无创性检测听皮层中与能量代谢及神经递质有关的化合物,纯音刺激单耳时,正常人对侧听皮层代谢变化明显大于同侧,表现为对侧半球传导优势。

Objective To study biochemical changes in the auditory cortex evoked by pure tone stimuli in healthy subjects using proton magnetic resonance spectroscopy （1H-MRS）. Methods MRS tests were performed in 10 healthy volunteers （6 males and 4 females） before and after left ear stimulation with a 1000 Hz pure tone at 90 dB HL. N-aeeytlaspartate （NAA）, ereatine （Cr）, choline （Cho） and glutamate/glutamine （Glx） values in the auditory cortex were analyzed with semi-quantitative methodologies. Results The NAA/（Cho＋Cr） and Glx/（Cho＋Cr） ratios increased in the Hesehl＇s gyrus bilaterally after pure tone stimulation, while the Cho/Cr ratio decreased. The changes were statistically significant on the right side （P 〈 0.05）, but not in the left auditory cortex （P 〉 0.05）. Conclusion Proton MR spectroscopy is a new noninvasive method which can be used to detect a number of chemical compounds pertaining to energy metabolism and neurotransmitters in the auditory cortex. Unilateral pure tone stimulation induces biochemical changes greater in the contralateral auditory cortex than in the ipsilateral auditory cortex, showing a clear contralateral predominancey.