【作者】 谭江秀；

【导师】 孙心德；

【作者基本信息】 华东师范大学 ， 生理学， 2007， 硕士

【摘要】 应用常规电生理学技术,以神经元的特征频率(characteristic frequency,CF)和频率调谐曲线(Frequency tuning curve,FTC)为指标,分别在生后2、3、4、5、6和8周龄SD大鼠上,研究生后发育过程中,听皮层神经元的反应特性以及神经元特征频率的可塑性。实验分为两大部分:一,大鼠发育过程中初级听皮层神经元的反应特性本实验应用常规电生理学技术,分析了生后2、3、4、5、6和8周龄这六个不同年龄段SD大鼠听皮层神经元的反应特性。1.在生后2、3、4、5、6和8周龄这六个不同年龄段大鼠记到的神经元中,其特征频率(characteristic frequency,CF)范围随着年龄而递增。2、3周龄动物CF相对比较低。2.随着年龄的增长,神经元最低反应阈值逐渐递减。年龄越小,其神经元的最低反应阈值则越高,同样,神经元反应潜伏期也随着年龄的增长而逐渐递减。年龄越大,神经元的平均潜伏期越小。3.相反,神经元平均Q10-dB值则是随着年龄的增长而逐渐递增的;年龄越大,神经元的平均Q10-dB值越大。4.在生后2、3、4、5、6和8周龄这六个不同年龄段大鼠记到的神经元中,其频率调谐曲线(Frequency tuning curve,FTC)是随着年龄而逐渐变窄的。年龄越小,其神经元的FTC越宽,且出现多峰现象。二,大鼠发育过程中初级听皮层神经元的频率感受野可塑性特性应用常规电生理学技术,以神经元的特征频率和频率调谐曲线为指标,分别在生后2、3、4、5、6和8周龄SD大鼠上,研究生后发育过程中,听皮层神经元特征频率的可塑性。1.在给予条件刺激频率(Conditioned stimulus frequency,CFS)和神经元特征频率相差1.0 kHz范围和相差2.0 kHz范围内,条件刺激都可诱导各年龄组神经元特征频率(characteristic frequency,CF)向频率调谐曲线(Frequencytuning curve,FTC)的低频端、高频端或调谐曲线的两端相应的偏移。2.随着出生后年龄的增长,无论是给予条件刺激频率和神经元特征频率相差1.0还是2.0 kHz,诱导神经元CF向高频端和低频端偏移的百分数都呈现逐渐递减的趋势,神经元CF既不向高频端也不向低频端偏移的百分比则随着年龄的增长而逐渐增加。3.随着年龄增长,那些Q,0-dB值大的神经元,特征频率偏移到频率调谐曲线高频端的比例增加更为明显(p<0.01)。4.随着年龄增长,那些频率调谐曲线对称指数大于零的神经元,特征频率偏移到频率调谐曲线高频端的比例增加更为明显(p<0.01)。5.诱导特征频率完全偏移的时程和特征频率恢复的时程也与动物的年龄相关,随着年龄增长,诱导和恢复时程都明显延长(p<0.05)。研究结果为深入研究中枢神经元功能活动可塑性的机制提供了重要的实验资料。更多还原

【Abstract】 Using conventional electrophysiological technique, we investigated auditory response properties and the plasticity of characteristic frequency （CF） of neurons in rat auditory cortex （AC） at postnatal age of two , three , four , five , six and eight week by determining CF and frequency tuning curve （FTC） shifts of neurons.1. Auditory response properties and neurons in rat auditory cortex （AC） at postnatal age of two , three , four , five , six and eight week.（1）. The older is the age, the larger is the characteristic frequency （CF） ; characteristic frequency （CF） is much lower, when at postnatal age of two, three week.（2）. The older is the age, the less is the mean minimum threshold and mean latency of the auditory cortex, the younger is the age, the minimum threshold of the auditory cortex is higher and latency of the auditory cortex.（3）. The older is the age, the larger is mean Q₁₀-dB values of the auditory cortex.（4）. The younger is the age, the more broad of frequency tuning curve （FTC） in the auditory cortex; there was multipeak, when at postnatal age of two, three week. 2. The plasticity of characteristic frequency （CF） of neurons in rat auditory cortex （AC） at postnatal age of two , three , four , five , six and eight week.（1）. When the frequency difference between conditioned stimulus frequency （CSF） and the CF of neuron was in 1.0 kHz or 2.0 kHz with conditioned stimulation, conditioned stimulus can induce CF shift toward higher frequency side （HFS）, lower frequency side （LFS） and both sides （BLH） of neuron’s FTC.（2）. The proportion of CF shift becomes lower and the proportion of non CF shift becomes higher with the increasing of the age.（3）. Neurons with bigger Q10-dB value of the FTC, increasing of the proportion of CF shift toward higher frequency side （HFS） of neuron’s FTC is much higher.（4）. Neurons with symmetry index >0 of the FTC, increasing of the proportion of CF shift toward higher frequency side （HFS） of neuron’s FTC is much higher.（5）. There is significant correlation between the time course and the age of rat, the older is the age, the longer is the shift time （p<0.05） and the recovery time （p<0.05） of neurons.These findings also provide evidence for further study of plasticity mechanisms in sensory function of the brain.更多还原