单眼剥夺性弱视小鼠图形视觉诱发电位时间频率调制变化的研究

目的 探讨单眼剥夺性弱视小鼠图形视觉诱发电位（PVEP）的时间频率调制的变化。方法 生后26 d健康C57BL/6J小鼠18只，随机均分为正常对照组和单眼剥夺（MD）组。MD组小鼠右眼眼睑行褥式缝合，5 d造成单眼形觉剥夺，建立弱视模型。对照组在相同环境下饲养至生后31 d。随后，2组小鼠均于视皮层硬脑膜表面埋置电极。于生后32 d在麻醉状态下对小鼠的右眼行不同时间频率（2.50、1.25、1.00、0.75、0.50和0.25 Hz）的图形视觉刺激，记录PVEP，比较2组在不同时间频率的视觉刺激下PVEP的P100波幅值的差异。结果 对照组小鼠对所有6种时间频率的PVEP P100波反应幅值差异无统计学意义（F=2.214，P＞0.05）；MD组小鼠对6种时间频率的PVEP P100波反应幅值差异有统计学意义（F=6.588，P＜0.01），其时间频率调制曲线表现为低通特性。与对照组相比，高时间频率（2.50和1.25 Hz）视觉刺激条件下，MD组P100波幅值显著降低（t分别为2.362和2.425，P＜0.05）。在中低时间频率（1.00、0.75、0.50和0.25 Hz）刺激条件下，与对照组相比，MD组的P100波反应幅值差异无统计学意义（均P＞0.05）。结论 MD小鼠对高时间频率视觉刺激的PVEP反应降低，而中低时间频率下的PVEP反应未受到明显影响。

Study on the changes of temporal frequency tuning curve of pattern visual evoked potentials inmonocular-deprived amblyopic mice

Objective To explore the changes of temporal frequency tuning of pattern visual evoked potentials inmonocular-deprived amblyopic mice. Methods Eighteen postnatal 26 days C57 BL/6J mice were randomly divided intothe normal control (Ctrl) group and the monocular deprivation (MD) group. The right eye of mice in the MD group was suturedwith mattress for 5 days of form deprivation to establish the amblyopic model. The Ctrl group was fed in the sameenvironment until postnatal 31 days. The electrodes were implanted on the dura above the visual cortex. The right eyes of themice were subjected to pattern visual stimulation at different termporal frequencies (2.50, 1.25, 1.00, 0.75, 0.5 and 0.25 Hz)under anesthesia on postnatal 32 days, and pattern visual evoked potentials (PVEP) were recorded. The difference of P100wave amplitudes of PVEP recorded under visual stimuli of different temporal frequencies was compared between the twogroups. Results There were no significant differences in the amplitudes of PVEP P100 waveforms evoked by stimuli of 6temporal frequencies between mice of the Ctrl group (F= 2.214, P＞0.05), while there were significant differences in theamplitudes of PVEP P100 waveforms evoked by stimuli of 6 temporal frequencies between mice of the MD group (F=6.588,P＜0.01), and its temporal frequency tuning curve showed low-passing feature. Under high temporal frequencies (2.50 and1.25 Hz), the P100 wave amplitudes significantly decreased in the MD group compared with the Ctrl group (t= 2.362 and2.425，P＜0.05). Under middle to low temporal frequencies (1.00, 0.75, 0.50 and 0.25 Hz), there was no significantdifference in the P100 wave amplitudes in the MD group compared with the Ctrl group (all P＞0.05). Conclusion ThePVEP responses to visual stimuli of high temporal frequencies are decreased in MD mice, but the responses to low temporal frequencies are not significantly influenced