摘要目的 利用质子磁共振波谱(proton magnetic resonance spectroscopy,1H-MRS)技术观察纯音刺激后正常人左右半球听皮层代谢物偏侧性变化.方法 12例健康受试者听皮层在纯音刺激前后各接受一次多体素磁共振波谱检查.刺激声音为声强90dB、频率1000Hz的正弦波纯音脉冲.观察双侧听皮层N-乙酰天门冬氨酸(NAA)、肌酸(Cr)、胆碱(Cho)、谷氨酰胺和谷氨酸(Glx)、GABA等代谢物的波峰变化,并进行半定量分析,比较刺激前后听皮层代谢物左右半球偏侧性变化.结果 纯音刺激后左侧听皮层NAA/(Cho+Cr)、GABA/Cr比值[分别为(1.28±0.14),(0.21±0.08)],高于刺激前[分别为(1.02±0.18),(0.10±0.05)],Glx/Cr比值[(0.03±0.02)]明显低于刺激前[(0.10±0.04)],差异均有统计学意义(P<0.05);右侧听皮层刺激后NAA/(Cho+Cr)、Glx/Cr比值[分别为(0.92±0.13),(0.09±0.05)]均高于刺激前[分别为(0.90±0.11),(0.08±0.03)],但差异无统计学意义(P>0.05);GABA/Cr比值[(0.01±0.11)]明显低于刺激前[(0.11±0.07)],差异有显著性(P<0.002),纯音刺激后双侧听皮层Glx/Cr比值呈明显的非对称性.结论 纯音刺激后双侧听皮层代谢存在半球非对称性,可能为功能的非对称性提供生化方面的信息.

abstractsObjective To explore the asymmetry of metabolic products of the auditory cortex in normal human brain after being stimulated by the pure tone with the proton magnetic resonance spectroscopy(1 H-MRS). Methods Twelve healthy volunteers, including 7 males and 5 females, were performed MRS tests before and after the stimulation of the pure tone of 90 dB in intensity and 1000 Hz in frequency. The the metabolites peak of the N-acetylaspartate (NAA) ,creatine(Cr) ,choline( Cho) , glutamine/glutamate ( Glx) and GABA in auditory cortex were investigated, The content of metabolic products were conducted with half-quantitative analysis. The differences of the NAA/( Cho + Cr) ,Glx/Cr and GABA/ Cr ratios before and after pure tone stimulation in the bilateral auditory cortex were analyzed. The difference of distribution of the metabolic products between the left and right auditory cortex was also analyzed to explore the asymmetry of the auditory cortex. Results The NAA/( Cho + Cr) and GABA/Cr ratios increased,the Glx/Cr ratio decreased in the left auditory cortex after being stimulated by the pure tone. There were significant differences in the NAA/( Cho + Cr) , Glx/Cr and GABA/Cr ratios before and after pure tone stimulation (P<0.05) ;the GABA/Cr ratio decreased,the Glx/Cr and NAA/( Cho + Cr) ratios increased in the right auditory cortex after being stimulated by the pure tone, and statistical difference of the GABA/Cr ratio was found before and after pure tone stimulation (P<0. 05) ,however the difference of the Glx/Cr and NAA/(Cho + Cr) ratios before and after pure tone stimulation was not significant (P>0.05). There were statistically significant differences in the Glx/Cr ratio of the auditory cortex between two sides after being stimulated by the pure tone. Conclusion The metabolic lateralization exists in auditory cortex of normal human brain after being stimulated by the pure tone, which may be the bases of the functional asymmetry.