老年小鼠与青年小鼠眨眼条件反射双任务模型中行为学参数的比较

目的研究老年昆明小鼠在眨眼条件反射双任务模型中的行为学特征参数变化。方法老年(15月龄)昆明小鼠组(n=5)及青年(3月龄)昆明小鼠组(n=5),采用不同音频(3、1 kHz)的正弦波纯音作为条件刺激(conditioned stimulus,CS),声音强度为70 dB。以持续时间100 ms压强3 psi(1 psi=6.895 kPa)的束状氧气流作为非条件刺激(uncon-ditioned stimulus,US)进行CS-US配对训练,观察2组动物在双任务眨眼条件射模型训练中其行为学参数的差异,包括眨眼条件反应(eyeblink conditioned responses,CR)、峰幅度(amplitude of peak,AP)、潜伏期(latency of peak,TP)。结果经过12 d配对训练:老年组与青年组在痕迹性眨眼条件反射和延迟性眨眼条件反射模式中,CR习得率均随训练天数增加而增加,组间CR习得率均从第10天起出现显著差异(P<0.05);在痕迹性眨眼条件反射模式中,2组间峰幅度从第10天起出现显著差异(P<0.05),在延迟性眨眼条件反射模式中2组间峰幅度在第6天和第12天有显著差异(P<0.05);2组组内高音频(3 kHz)CS对应的TEBC模式其习得率都要高于低音频(1 kHz)CS的DEBC模式其CR习得率。结论老年昆明小鼠较青年昆明小鼠而言不能很好地学习双任务眨眼条件反射,说明老化对于小鼠的联想型学习记忆有着直接影响。

Behavioral parameters in aging vs young mice during dual-task eyeblink conditioning

Objective To investigate the changes of behavioral parameters during dual-task eyeblink conditioning in aging Kunming mice.Methods A total of 5 15-month-old mice(aged group) and 5 3-month-old mice(young group) were assigned to receive paired training of tone(intensity of sound 70 dB) conditioned stimulus(CS) in different audio frequency(3 kHz and 1 kHz) and a 100-ms comeal oxygen-puff unconditioned stimulus(US).Behavioral parameters,including eyeblink conditioned responses(CR),amplitude of peak(AP) and latency of peak(TP) were observed,and the results were compared between the 2 groups.Results After 12 days’ pairing training,CR% in trace eyeblink conditioning(TEBC) and delay eyeblink conditioning(DEBC) was increased with the elapse of training days in both aged mice group and young mice group.CR acquisition rate between the 2 groups appears significantly different from the tenth day(P<0.05).There was significant difference in AP between the 2 groups from the tenth day in TEBC(P<0.05),and also on the sixth day and the twelfth day in DEBC(P<0.05).Surprisingly,acquisition rate of TEBC which trained with 3-kHz-CS was obviously higher than the DEBC with 1-kHz-CS in 2 groups.Conclusion Aged Kunming mice can not learn dual-task eyeblink conditioning well compared with young ones,which indicating that aging affects the association learning in mice directly.