幼年和成年豚鼠失匹配负波反应的特性

Responsibility of mismatch negativity in infant and adult guinea pigs

目的探讨豚鼠失匹配负波(mismatch negativity,MMN)的反应特点,观察声刺激频率和强度对不同年龄豚鼠MMN潜伏期和振幅的影响,建立测试动物MMN的方法。方法选择正常幼年和成年豚鼠各10只(20耳),在麻醉状态下行MMN和听觉脑干反应(auditory brainstem response,ABR)测试,分别比较两组豚鼠听觉功能差异。结果频率和强度差异诱发MMN成年鼠的潜伏期明显短于幼鼠,潜伏期差异皆有统计学意义(两者P均<0.05),而振幅差异无统计学意义(P>0.05)。两组豚鼠ABR除Ⅰ～Ⅲ波间期差异有显著性(P=0.04),其余各波潜伏期、波间期和阈值差异均无统计学意义(P>0.05)。结论豚鼠存在与人相似的MMN波形,并随年龄有一个发育、分化和成熟的过程,可作为研究MMN神经生理机制的实验动物。与ABR比较,MMN在检测听觉中枢功能的敏感性上更具有优势。

OBJECTIVE To explore the responsibility of mismatch negativity （MMN） in guinea pigs, and the effect on the latency and amplitude of MMN in infant and adult guinea pigs, and to set up an animal model of MMN recording technique. METHODS Ten normal infant and ten adult guinea pigs were served as subjects. Each guinea pig was anesthetized and recorded MMN and auditory brainstem response （ABR） with passive mode. The responsibility of MMNs and ABRs between infant and adult guinea pigs were compared. RESULTS The average latency of adult guinea pigs was shorter than that of infant guinea pigs when eliciting MMN by 1000Hz frequency and 50dB SPL intensity, which difference was statistically significant （P=0.002, P=0.006） . But there were no sianificant difference in amplitudes （P〉0.05） .Except for interwaves latency Ⅰ -Ⅲ（t=2.12, P=0.04）, both latencies for wave Ⅰ, Ⅲ and Ⅴ and interwaves latencies Ⅲ-Ⅴ, Ⅰ -Ⅴ and the threshold of wave Ⅲ were no significant difference between two groups （P〉0.05） . CONCLUSION A similar MMN exists in guinea pigs and human. MMN has a process of development, differentiation and maturation with aging.Guinea pigs can serve as the candidate animal for MMN research. Comparing with ABR, MMN is more sensitive to evaluate the central auditory function.