中文摘要：

为进一步研究损伤神经放电节律的分岔转迁规律,以实验性神经起步点模型为研究对象,在联合改变胞外的钙离子和钾离子浓度的条件下,记录神经单纤维的放电节律转迁方式。选取4-氨基吡啶（4-aminopyridine,4-AP）作为条件参数,Ca2＋浓度作为分岔参数,观察了实验性神经起步点自发放电节律的分岔规律。28例实验结果中,有21例神经对本文所取的条件参数变化不敏感,7例实验性神经起步点的自发放电节律会在不同的条件参数下出现不同类型的分岔序列结构。在不同的4-AP浓度下,随着Ca^2＋浓度的降低,同一实验性神经起步点会表现出不同的放电节律模式的分岔序列,不同实验性神经起步点,双参数分岔序列是不同的。以上结果说明,不同参数配置下的神经放电节律的变化规律是不同的,而且分岔序列结构是认识放电节律转迁规律的基础。

英文摘要：

Neuronal firing is crucial to the information processing in the nervous system.In order to make a further study of bifurcation scenarios,experiments were performed on neural pacemakers formed at the injured site of rat sciatic nerve subjected to chronic ligatures.We chose the conductance of voltage-dependent potassium ion channels as conditional parameter,and the extracellular calcium concentration as bifurcation parameter,to give a demonstration of how the firing pattern of neural pacemaker responses to dual parameter adjusting.Among 28 preparations observed,21 were insensitive to dual parameter adjusting since no change of bifurcation scenario structure was detected.On the contrary,the residual 7 preparations showed dramatic bifurcation scenario shifting corresponding to different dual parameter configuration.Briefly,when concentration of 4-aminopyridine （4-AP）,a voltage-dependent potassium ion channels blocker,was kept at different level and extracellular Ca^2＋ concentration was decreased gradually,different bifurcation scenarios of firing patterns were exhibited in an identical neural pacemaker.The two-parameter bifurcation scenarios of experimental neural pacemaker with different parameter configuration were also different.The results show that neural firing pattern is different when the parameter configuration is different,and the bifurcation scenario is a fundamental framework to identify the transitions between firing patterns.